1
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Yoshidome T. Four-dimensional imaging for cryo-electron microscopy experiments using molecular simulations and manifold learning. J Comput Chem 2024; 45:738-751. [PMID: 38112413 DOI: 10.1002/jcc.27290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Revised: 11/20/2023] [Accepted: 12/01/2023] [Indexed: 12/21/2023]
Abstract
Elucidating protein conformational changes is essential because conformational changes are closely related to the functions of proteins. Cryo-electron microscopy (cryo-EM) experiment can be used to reconstruct protein conformational changes via a method that involves using the experimental data (two-dimensional protein images). In this study, a reconstruction method, referred to as the "four-dimensional imaging," was proposed. In our four-dimensional imaging technique, the protein conformational change was obtained using the two-dimensional protein images (the three-dimensional electron density maps used in previously proposed techniques were not used). The protein conformation for each two-dimensional protein image was obtained using our original protocol with molecular dynamics simulations. Using a manifold-learning technique and two-dimensional protein images, the protein conformations were arranged according to the conformational change of the protein. By arranging the protein conformations according to the arrangement of the protein images, four-dimensional imaging is constructed. A simulation for a cryo-EM experiment demonstrated the validity of our four-dimensional imaging technique.
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Affiliation(s)
- Takashi Yoshidome
- Department of Applied Physics, Graduate School of Engineering, Tohoku University, Sendai, Japan
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2
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Lin H, Li J, Zhang Q, Yang H, Chen S. C-type inactivation and proton modulation mechanisms of the TASK3 channel. Proc Natl Acad Sci U S A 2024; 121:e2320345121. [PMID: 38630723 DOI: 10.1073/pnas.2320345121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 03/19/2024] [Indexed: 04/19/2024] Open
Abstract
The TWIK-related acid-sensitive K+ channel 3 (TASK3) belongs to the two-pore domain (K2P) potassium channel family, which regulates cell excitability by mediating a constitutive "leak" potassium efflux in the nervous system. Extracellular acidification inhibits TASK3 channel, but the molecular mechanism by which channel inactivation is coupled to pH decrease remains unclear. Here, we report the cryo-electron microscopy structures of human TASK3 at neutral and acidic pH. Structural comparison revealed selectivity filter (SF) rearrangements upon acidification, characteristic of C-type inactivation, but with a unique structural basis. The extracellular mouth of the SF was prominently dilated and simultaneously blocked by a hydrophobic gate. His98 protonation shifted the conformational equilibrium between the conductive and C-type inactivated SF toward the latter by engaging a cation-π interaction with Trp78, consistent with molecular dynamics simulations and electrophysiological experiments. Our work illustrated how TASK3 is gated in response to extracellular pH change and implies how physiological stimuli might directly modulate the C-type gating of K2P channels.
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Affiliation(s)
- Huajian Lin
- Shanghai Institute of Precision Medicine, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200125, China
- Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai 200125, China
| | - Junnan Li
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Qiansen Zhang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Huaiyu Yang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Shanshuang Chen
- Shanghai Institute of Precision Medicine, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200125, China
- Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai 200125, China
- Department of Otolaryngology-Head and Neck Surgery, Ninth People's Hospital, Shanghai 200011, China
- Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai 200125, China
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3
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Kimura-Someya T, Katsura K, Kato-Murayama M, Hosaka T, Uchikubo-Kamo T, Ihara K, Hanada K, Sato S, Murayama K, Kataoka M, Shirouzu M, Someya Y. Structural analyses of the GI.4 norovirus by cryo-electron microscopy and X-ray crystallography revealing binding sites for human monoclonal antibodies. J Virol 2024:e0019724. [PMID: 38593321 DOI: 10.1128/jvi.00197-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Accepted: 03/21/2024] [Indexed: 04/11/2024] Open
Abstract
Noroviruses are major causative agents of acute nonbacterial gastroenteritis in humans. There are neither antiviral therapeutic agents nor vaccines for noroviruses at this time. To evaluate the potential usefulness of two previously isolated human monoclonal antibody fragments, CV-1A1 and CV-2F5, we first conducted a single-particle analysis to determine the cryo-electron microscopy structure of virus-like particles (VLPs) from the genogroup I genotype 4 (GI.4) Chiba strain uniformly coated with CV-1A1 fragments. The results revealed that the GI.4-specific CV-1A1 antibody bound to the P2 subdomain, in which amino acids are less conserved and variable. Interestingly, a part of the CV-1A1 intrudes into the histo-blood group antigen-binding site, suggesting that this antibody might exert neutralizing activity. Next, we determined the crystal structure of the protruding (P) domain of the capsid protein in the complex form with the CV-2F5 antibody fragment. Consistent with the cross-reactivity, the CV-2F5 bound to the P1 subdomain, which is rich in amino acids conserved among the GI strains, and moreover induced a disruption of Chiba VLPs. These results suggest that the broadly reactive CV-2F5 antibody can be used as both a universal detection reagent and an antiviral drug for GI noroviruses. IMPORTANCE We conducted the structural analyses of the VP1 protein from the GI.4 Chiba norovirus to identify the binding sites of the previously isolated human monoclonal antibodies CV-1A1 and CV-2F5. The cryo-electron microscopy of the Chiba virus-like particles (VLPs) complexed with the Fv-clasp forms of GI.4-specific CV-1A1 revealed that this antibody binds to the highly variable P2 subdomain, suggesting that this antibody may have neutralizing ability against the GI.4 strains. X-ray crystallography revealed that the CV-2F5 antibody bound to the P1 subdomain, which is rich in conserved amino acids. This result is consistent with the ability of the CV-2F5 antibody to react with a wide variety of GI norovirus strains. It is also found that the CV-2F5 antibody caused a disruption of VLPs. Our findings, together with previous reports on the structures of VP1 proteins and VLPs, are expected to open a path for the structure-based development of antivirals and vaccines against norovirus disease.
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Affiliation(s)
| | - Kazushige Katsura
- RIKEN Center for Biosystems Dynamics Research, Yokohama, Kanagawa, Japan
| | | | - Toshiaki Hosaka
- RIKEN Center for Biosystems Dynamics Research, Yokohama, Kanagawa, Japan
| | | | - Kentaro Ihara
- RIKEN Center for Biosystems Dynamics Research, Yokohama, Kanagawa, Japan
| | - Kazuharu Hanada
- RIKEN Center for Biosystems Dynamics Research, Yokohama, Kanagawa, Japan
| | - Shin Sato
- RIKEN Center for Biosystems Dynamics Research, Yokohama, Kanagawa, Japan
| | - Kazutaka Murayama
- RIKEN Center for Biosystems Dynamics Research, Yokohama, Kanagawa, Japan
- Graduate School of Biomedical Engineering, Tohoku University, Sendai, Miyagi, Japan
| | - Michiyo Kataoka
- Department of Pathology, National Institute of Infectious Diseases, Tokyo, Japan
| | - Mikako Shirouzu
- RIKEN Center for Biosystems Dynamics Research, Yokohama, Kanagawa, Japan
| | - Yuichi Someya
- Department of Virology II, National Institute of Infectious Diseases, Tokyo, Japan
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4
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Bu F, Wang X, Li M, Ma L, Wang C, Hu Y, Cao Z, Liu B. Cryo-EM Structure of Porphyromonas gingivalis RNA Polymerase. J Mol Biol 2024; 436:168568. [PMID: 38583515 DOI: 10.1016/j.jmb.2024.168568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Revised: 04/01/2024] [Accepted: 04/02/2024] [Indexed: 04/09/2024]
Abstract
Porphyromonas gingivalis, an anaerobic CFB (Cytophaga, Fusobacterium, and Bacteroides) group bacterium, is the keystone pathogen of periodontitis and has been implicated in various systemic diseases. Increased antibiotic resistance and lack of effective antibiotics necessitate a search for new intervention strategies. Here we report a 3.5 Å resolution cryo-EM structure of P. gingivalis RNA polymerase (RNAP). The structure displays new structural features in its ω subunit and multiple domains in β and β' subunits, which differ from their counterparts in other bacterial RNAPs. Superimpositions with E. coli RNAP holoenzyme and initiation complex further suggest that its ω subunit may contact the σ4 domain, thereby possibly contributing to the assembly and stabilization of initiation complexes. In addition to revealing the unique features of P. gingivalis RNAP, our work offers a framework for future studies of transcription regulation in this important pathogen, as well as for structure-based drug development.
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Affiliation(s)
- Fan Bu
- Section of Transcription & Gene Regulation, The Hormel Institute, University of Minnesota, Austin, MN, USA
| | - Xiaoxuan Wang
- State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST KLOS) & Key Laboratory of Oral Biomedicine Ministry of Education (KLOBME), School & Hospital of Stomatology, Wuhan University, Wuhan, China; Department of Periodontology, School & Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Mengke Li
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, China
| | - Li Ma
- State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST KLOS) & Key Laboratory of Oral Biomedicine Ministry of Education (KLOBME), School & Hospital of Stomatology, Wuhan University, Wuhan, China; Department of Periodontology, School & Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Chuan Wang
- State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST KLOS) & Key Laboratory of Oral Biomedicine Ministry of Education (KLOBME), School & Hospital of Stomatology, Wuhan University, Wuhan, China; Department of Periodontology, School & Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Yangbo Hu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, China.
| | - Zhengguo Cao
- State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST KLOS) & Key Laboratory of Oral Biomedicine Ministry of Education (KLOBME), School & Hospital of Stomatology, Wuhan University, Wuhan, China; Department of Periodontology, School & Hospital of Stomatology, Wuhan University, Wuhan, China.
| | - Bin Liu
- Section of Transcription & Gene Regulation, The Hormel Institute, University of Minnesota, Austin, MN, USA.
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Eiler DR, Wimberly BT, Bilodeau DY, Taliaferro JM, Reigan P, Rissland OS, Kieft JS. The Giardia lamblia ribosome structure reveals divergence in several biological pathways and the mode of emetine function. Structure 2024; 32:400-410.e4. [PMID: 38242118 PMCID: PMC10997490 DOI: 10.1016/j.str.2023.12.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 10/23/2023] [Accepted: 12/23/2023] [Indexed: 01/21/2024]
Abstract
Giardia lamblia is a deeply branching protist and a human pathogen. Its unusual biology presents the opportunity to explore conserved and fundamental molecular mechanisms. We determined the structure of the G. lamblia 80S ribosome bound to tRNA, mRNA, and the antibiotic emetine by cryo-electron microscopy, to an overall resolution of 2.49 Å. The structure reveals rapidly evolving protein and nucleotide regions, differences in the peptide exit tunnel, and likely altered ribosome quality control pathways. Examination of translation initiation factor binding sites suggests these interactions are conserved despite a divergent initiation mechanism. Highlighting the potential of G. lamblia to resolve conserved biological principles; our structure reveals the interactions of the translation inhibitor emetine with the ribosome and mRNA, thus providing insight into the mechanism of action for this widely used antibiotic. Our work defines key questions in G. lamblia and motivates future experiments to explore the diversity of eukaryotic gene regulation.
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Affiliation(s)
- Daniel R Eiler
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Brian T Wimberly
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Danielle Y Bilodeau
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80045, USA; RNA BioScience Initiative, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - J Matthew Taliaferro
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80045, USA; RNA BioScience Initiative, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Philip Reigan
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Olivia S Rissland
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80045, USA; RNA BioScience Initiative, University of Colorado School of Medicine, Aurora, CO 80045, USA.
| | - Jeffrey S Kieft
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80045, USA; RNA BioScience Initiative, University of Colorado School of Medicine, Aurora, CO 80045, USA.
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6
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Ghosh U, Tse E, Shi M, Yang H, Wang F, Merz GE, Prusiner SB, Southworth DR, Condello C. Cryo-EM Structures Reveal Tau Filaments from Down Syndrome Adopt Alzheimer's Disease Fold. bioRxiv 2024:2024.04.02.587507. [PMID: 38617229 PMCID: PMC11014571 DOI: 10.1101/2024.04.02.587507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
Down Syndrome (DS) is a common genetic condition caused by trisomy of chromosome 21. Among the complex clinical features including musculoskeletal, neurological and cardiovascular disabilities, individuals with DS develop progressive dementia and early onset Alzheimer's Disease (AD). This is attributed to the increased gene dosage of amyloid precursor protein (APP), the formation of self-propagating Aβ and tau prion conformers, and the deposition of neurotoxic Aβ plaques and tau neurofibrillary tangles. Tau amyloid fibrils have previously been established to adopt many distinct conformations across different neurodegenerative conditions. Here we characterized 4 DS cases spanning 36 to 63 years in age by spectral confocal imaging with conformation-specific dyes and cryo-electron microscopy (cryo-EM) to determine structures of isolated tau fibrils. High-resolution structures reveal paired helical (PHF) and straight filament (SF) conformations of tau that are identical to those determined from AD. The PHFs and SFs are made of two C-shaped protofilaments with a cross-β/β-helix motif. Similar to AD, most filaments adopt the PHF form, while a minority (~20%) form SFs. For the youngest individual with no documented dementia samples exhibited sparse tau deposits. To isolate tau for cryo-EM from this challenging sample we employed a novel "affinity grid" method involving a graphene-oxide surface derivatized with anti-tau antibodies. This improved isolation and revealed primarily tau PHFs and a minor population of SSPE type II-like filaments are present at this early age. These findings expand the similarities between AD and DS to the molecular level providing insight into their related pathologies and the potential for targeting common tau filament folds by small molecule therapeutics and diagnostics.
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Affiliation(s)
- Ujjayini Ghosh
- Institute for Neurodegenerative Diseases; University of California, San Francisco; San Francisco, CA 94158, USA
| | - Eric Tse
- Institute for Neurodegenerative Diseases; University of California, San Francisco; San Francisco, CA 94158, USA
| | - Marie Shi
- Institute for Neurodegenerative Diseases; University of California, San Francisco; San Francisco, CA 94158, USA
| | - Hyunjun Yang
- Institute for Neurodegenerative Diseases; University of California, San Francisco; San Francisco, CA 94158, USA
| | - Feng Wang
- Department of Biochemistry and Biophysics, University of California San Francisco; San Francisco, CA, USA
| | - Gregory E. Merz
- Institute for Neurodegenerative Diseases; University of California, San Francisco; San Francisco, CA 94158, USA
- Department of Neurology, University of California San Francisco; San Francisco, CA, USA
| | - Stanley B. Prusiner
- Institute for Neurodegenerative Diseases; University of California, San Francisco; San Francisco, CA 94158, USA
- Department of Neurology, University of California San Francisco; San Francisco, CA, USA
- Department of Biochemistry and Biophysics, University of California San Francisco; San Francisco, CA, USA
| | - Daniel R. Southworth
- Institute for Neurodegenerative Diseases; University of California, San Francisco; San Francisco, CA 94158, USA
- Department of Biochemistry and Biophysics, University of California San Francisco; San Francisco, CA, USA
| | - Carlo Condello
- Institute for Neurodegenerative Diseases; University of California, San Francisco; San Francisco, CA 94158, USA
- Department of Neurology, University of California San Francisco; San Francisco, CA, USA
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7
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Mueller-Dieckmann C, Grinzato A, Effantin G, Fenel D, Flot D, Schoehn G, Leonard G, Kandiah E. From solution to structure: empowering inclusive cryo-EM with a pre-characterization pipeline for biological samples. J Appl Crystallogr 2024; 57:602-605. [PMID: 38596739 PMCID: PMC11001406 DOI: 10.1107/s1600576724001717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Accepted: 02/20/2024] [Indexed: 04/11/2024] Open
Abstract
In addressing the challenges faced by laboratories and universities with limited (or no) cryo-electron microscopy (cryo-EM) infrastructure, the ESRF, in collaboration with the Grenoble Institute for Structural Biology (IBS), has implemented the cryo-EM Solution-to-Structure (SOS) pipeline. This inclusive process, spanning grid preparation to high-resolution data collection, covers single-particle analysis and cryo-electron tomography (cryo-ET). Accessible through a rolling access route, proposals undergo scientific merit and technical feasibility evaluations. Stringent feasibility criteria demand robust evidence of sample homogeneity. Two distinct entry points are offered: users can either submit purified protein samples for comprehensive processing or initiate the pipeline with already vitrified cryo-EM grids. The SOS pipeline integrates negative stain imaging (exclusive to protein samples) as a first quality step, followed by cryo-EM grid preparation, grid screening and preliminary data collection for single-particle analysis, or only the first two steps for cryo-ET. In both cases, if the screening steps are successfully completed, high-resolution data collection will be carried out using a Titan Krios microscope equipped with a latest-generation direct electron counting detector coupled to an energy filter. The SOS pipeline thus emerges as a comprehensive and efficient solution, further democratizing access to cryo-EM research.
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Affiliation(s)
- Christoph Mueller-Dieckmann
- Structural Biology, European Synchrotron Radiation Facility (ESRF), 71 Avenue des Martyrs, Grenoble 38000, France
| | - Alessandro Grinzato
- Structural Biology, European Synchrotron Radiation Facility (ESRF), 71 Avenue des Martyrs, Grenoble 38000, France
| | | | - Daphna Fenel
- Univ. Grenoble Alpes, CNRS, CEA, IBS, Grenoble 38000, France
| | - David Flot
- Structural Biology, European Synchrotron Radiation Facility (ESRF), 71 Avenue des Martyrs, Grenoble 38000, France
| | - Guy Schoehn
- Univ. Grenoble Alpes, CNRS, CEA, IBS, Grenoble 38000, France
| | - Gordon Leonard
- Structural Biology, European Synchrotron Radiation Facility (ESRF), 71 Avenue des Martyrs, Grenoble 38000, France
| | - Eaazhisai Kandiah
- Structural Biology, European Synchrotron Radiation Facility (ESRF), 71 Avenue des Martyrs, Grenoble 38000, France
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8
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Wang L, Zimanyi CM. Cryo-EM sample preparation for high-resolution structure studies. Acta Crystallogr F Struct Biol Commun 2024; 80:S2053230X24002553. [PMID: 38530656 DOI: 10.1107/s2053230x24002553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2024] [Accepted: 03/18/2024] [Indexed: 03/28/2024] Open
Abstract
High-resolution structures of biomolecules can be obtained using single-particle cryo-electron microscopy (SPA cryo-EM), and the rapidly growing number of structures solved by this method is encouraging more researchers to utilize this technique. As with other structural biology methods, sample preparation for an SPA cryo-EM data collection requires some expertise and an understanding of the strengths and limitations of the technique in order to make sensible decisions in the sample-preparation process. In this article, common strategies and pitfalls are described and practical advice is given to increase the chances of success when starting an SPA cryo-EM project.
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Affiliation(s)
- Liguo Wang
- Laboratory for BioMolecular Structure, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Christina M Zimanyi
- National Center for CryoEM Access and Training, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY 10027, USA
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9
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Dedden D, Nitsche J, Schneider EV, Thomsen M, Schwarz D, Leuthner B, Grädler U. Cryo-EM Structures of CRAF 2/14-3-3 2 and CRAF 2/14-3-3 2/MEK1 2 Complexes. J Mol Biol 2024; 436:168483. [PMID: 38331211 DOI: 10.1016/j.jmb.2024.168483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 12/22/2023] [Accepted: 02/02/2024] [Indexed: 02/10/2024]
Abstract
RAF protein kinases are essential effectors in the MAPK pathway and are important cancer drug targets. Structural understanding of RAF activation is so far based on cryo-electron microscopy (cryo-EM) and X-ray structures of BRAF in different conformational states as inactive or active complexes with KRAS, 14-3-3 and MEK1. In this study, we have solved the first cryo-EM structures of CRAF2/14-3-32 at 3.4 Å resolution and CRAF2/14-3-32/MEK12 at 4.2 Å resolution using CRAF kinase domain expressed as constitutively active Y340D/Y341D mutant in insect cells. The overall architecture of our CRAF2/14-3-32 and CRAF2/14-3-32/MEK12 cryo-EM structures is highly similar to corresponding BRAF structures in complex with 14-3-3 or 14-3-3/MEK1 and represent the activated dimeric RAF conformation. Our CRAF cryo-EM structures provide additional insights into structural understanding of the activated CRAF2/14-3-32/MEK12 complex.
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Affiliation(s)
- Dirk Dedden
- Proteros biostructures GmbH, Bunsenstraße 7a, D-82152 Planegg-Martinsried, Germany
| | - Julius Nitsche
- Proteros biostructures GmbH, Bunsenstraße 7a, D-82152 Planegg-Martinsried, Germany
| | | | - Maren Thomsen
- Proteros biostructures GmbH, Bunsenstraße 7a, D-82152 Planegg-Martinsried, Germany
| | - Daniel Schwarz
- The Healthcare Business of Merck KGaA, Frankfurter Str. 250, 64293 Darmstadt, Germany
| | - Birgitta Leuthner
- The Healthcare Business of Merck KGaA, Frankfurter Str. 250, 64293 Darmstadt, Germany
| | - Ulrich Grädler
- The Healthcare Business of Merck KGaA, Frankfurter Str. 250, 64293 Darmstadt, Germany.
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10
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Li M, Zhang C, Xu Y, Li S, Huang C, Wu J, Lei M. Structural insights into human EMC and its interaction with VDAC. Aging (Albany NY) 2024; 16:5501-5525. [PMID: 38517390 PMCID: PMC11006472 DOI: 10.18632/aging.205660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Accepted: 02/08/2024] [Indexed: 03/23/2024]
Abstract
The endoplasmic reticulum (ER) membrane protein complex (EMC) is a conserved, multi-subunit complex acting as an insertase at the ER membrane. Growing evidence shows that the EMC is also involved in stabilizing and trafficking membrane proteins. However, the structural basis and regulation of its multifunctionality remain elusive. Here, we report cryo-electron microscopy structures of human EMC in apo- and voltage-dependent anion channel (VDAC)-bound states at resolutions of 3.47 Å and 3.32 Å, respectively. We discovered a specific interaction between VDAC proteins and the EMC at mitochondria-ER contact sites, which is conserved from yeast to humans. Moreover, we identified a gating plug located inside the EMC hydrophilic vestibule, the substrate-binding pocket for client insertion. Conformation changes of this gating plug during the apo-to-VDAC-bound transition reveal that the EMC unlikely acts as an insertase in the VDAC1-bound state. Based on the data analysis, the gating plug may regulate EMC functions by modifying the hydrophilic vestibule in different states. Our discovery offers valuable insights into the structural basis of EMC's multifunctionality.
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Affiliation(s)
- Mingyue Li
- Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, China
- Shanghai Institute of Precision Medicine, Shanghai 200125, China
| | - Chunli Zhang
- Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, China
- Shanghai Institute of Precision Medicine, Shanghai 200125, China
| | - Yuntao Xu
- Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, China
- Shanghai Institute of Precision Medicine, Shanghai 200125, China
| | - Shaobai Li
- Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, China
- Shanghai Institute of Precision Medicine, Shanghai 200125, China
| | - Chenhui Huang
- Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, China
- Shanghai Institute of Precision Medicine, Shanghai 200125, China
| | - Jian Wu
- Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, China
- Shanghai Institute of Precision Medicine, Shanghai 200125, China
| | - Ming Lei
- Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, China
- Shanghai Institute of Precision Medicine, Shanghai 200125, China
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
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11
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Zhang Z, Yan Y, Pang J, Dai L, Zhang Q, Yu EW. Structural basis of DNA recognition of the Campylobacter jejuni CosR regulator. mBio 2024; 15:e0343023. [PMID: 38323832 PMCID: PMC10936212 DOI: 10.1128/mbio.03430-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Accepted: 01/09/2024] [Indexed: 02/08/2024] Open
Abstract
Campylobacter jejuni is a foodborne pathogen commonly found in the intestinal tracts of animals. This pathogen is a leading cause of gastroenteritis in humans. Besides its highly infectious nature, C. jejuni is increasingly resistant to a number of clinically administrated antibiotics. As a consequence, the Centers for Disease Control and Prevention has designated antibiotic-resistant Campylobacter as a serious antibiotic resistance threat in the United States. The C. jejuni CosR regulator is essential to the viability of this bacterium and is responsible for regulating the expression of a number of oxidative stress defense enzymes. Importantly, it also modulates the expression of the CmeABC multidrug efflux system, the most predominant and clinically important system in C. jejuni that mediates resistance to multiple antimicrobials. Here, we report structures of apo-CosR and CosR bound with a 21 bp DNA sequence located at the cmeABC promotor region using both single-particle cryo-electron microscopy and X-ray crystallography. These structures allow us to propose a novel mechanism for CosR regulation that involves a long-distance conformational coupling and rearrangement of the secondary structural elements of the regulator to bind target DNA. IMPORTANCE Campylobacter jejuni has emerged as an antibiotic-resistant threat worldwide. CosR is an essential regulator for this bacterium and is important for Campylobacter adaptation to various stresses. Here, we describe the structural basis of CosR binding to target DNA as determined by cryo-electron microscopy and X-ray crystallography. Since CosR is a potential target for intervention, our studies may facilitate the development of novel therapeutics to combat C. jejuni infection.
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Affiliation(s)
- Zhemin Zhang
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
| | - Yuqi Yan
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
| | - Jinji Pang
- Department of Veterinary Microbiology, College of Veterinary Medicine, Iowa State University, Ames, Iowa, USA
| | - Lei Dai
- Department of Veterinary Microbiology, College of Veterinary Medicine, Iowa State University, Ames, Iowa, USA
| | - Qijing Zhang
- Department of Veterinary Microbiology, College of Veterinary Medicine, Iowa State University, Ames, Iowa, USA
| | - Edward W. Yu
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
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12
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Huang Q, Zhou Y, Liu HF, Bartesaghi A. Joint micrograph denoising and protein localization in cryo-electron microscopy. Biol Imaging 2024; 4:e4. [PMID: 38571546 PMCID: PMC10988173 DOI: 10.1017/s2633903x24000035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 12/30/2023] [Accepted: 02/05/2024] [Indexed: 04/05/2024]
Abstract
Cryo-electron microscopy (cryo-EM) is an imaging technique that allows the visualization of proteins and macromolecular complexes at near-atomic resolution. The low electron doses used to prevent radiation damage to the biological samples result in images where the power of noise is 100 times stronger than that of the signal. Accurate identification of proteins from these low signal-to-noise ratio (SNR) images is a critical task, as the detected positions serve as inputs for the downstream 3D structure determination process. Current methods either fail to identify all true positives or result in many false positives, especially when analyzing images from smaller-sized proteins that exhibit extremely low contrast, or require manual labeling that can take days to complete. Acknowledging the fact that accurate protein identification is dependent upon the visual interpretability of micrographs, we propose a framework that can perform denoising and detection in a joint manner and enable particle localization under extremely low SNR conditions using self-supervised denoising and particle identification from sparsely annotated data. We validate our approach on three challenging single-particle cryo-EM datasets and projection images from one cryo-electron tomography dataset with extremely low SNR, showing that it outperforms existing state-of-the-art methods used for cryo-EM image analysis by a significant margin. We also evaluate the performance of our algorithm under decreasing SNR conditions and show that our method is more robust to noise than competing methods.
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Affiliation(s)
- Qinwen Huang
- Department of Computer Science, Duke University, Durham27708, NC, USA
| | - Ye Zhou
- Department of Computer Science, Duke University, Durham27708, NC, USA
| | - Hsuan-Fu Liu
- Department of Biochemistry, Duke University School of Medicine, Durham27705, NC, USA
| | - Alberto Bartesaghi
- Department of Computer Science, Duke University, Durham27708, NC, USA
- Department of Biochemistry, Duke University School of Medicine, Durham27705, NC, USA
- Department of Electrical and Computer Engineering, Duke University, Durham27708, NC, USA
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13
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Cebi E, Lee J, Subramani VK, Bak N, Oh C, Kim KK. Cryo-electron microscopy-based drug design. Front Mol Biosci 2024; 11:1342179. [PMID: 38501110 PMCID: PMC10945328 DOI: 10.3389/fmolb.2024.1342179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Accepted: 01/31/2024] [Indexed: 03/20/2024] Open
Abstract
Structure-based drug design (SBDD) has gained popularity owing to its ability to develop more potent drugs compared to conventional drug-discovery methods. The success of SBDD relies heavily on obtaining the three-dimensional structures of drug targets. X-ray crystallography is the primary method used for solving structures and aiding the SBDD workflow; however, it is not suitable for all targets. With the resolution revolution, enabling routine high-resolution reconstruction of structures, cryogenic electron microscopy (cryo-EM) has emerged as a promising alternative and has attracted increasing attention in SBDD. Cryo-EM offers various advantages over X-ray crystallography and can potentially replace X-ray crystallography in SBDD. To fully utilize cryo-EM in drug discovery, understanding the strengths and weaknesses of this technique and noting the key advancements in the field are crucial. This review provides an overview of the general workflow of cryo-EM in SBDD and highlights technical innovations that enable its application in drug design. Furthermore, the most recent achievements in the cryo-EM methodology for drug discovery are discussed, demonstrating the potential of this technique for advancing drug development. By understanding the capabilities and advancements of cryo-EM, researchers can leverage the benefits of designing more effective drugs. This review concludes with a discussion of the future perspectives of cryo-EM-based SBDD, emphasizing the role of this technique in driving innovations in drug discovery and development. The integration of cryo-EM into the drug design process holds great promise for accelerating the discovery of new and improved therapeutic agents to combat various diseases.
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Affiliation(s)
| | | | | | | | - Changsuk Oh
- Department of Precision Medicine, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Kyeong Kyu Kim
- Department of Precision Medicine, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
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14
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Chen L, Fukata Y, Murata K. In situ cryo-electron tomography: a new method to elucidate cytoplasmic zoning at the molecular level. J Biochem 2024; 175:187-193. [PMID: 38102736 DOI: 10.1093/jb/mvad102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Accepted: 11/15/2023] [Indexed: 12/17/2023] Open
Abstract
Cryo-electron microscopy was developed as a powerful tool for imaging biological specimens in near-native conditions. Nowadays, advances in technology, equipment and computations make it possible to obtain structures of biomolecules with near-atomic resolution. Furthermore, cryo-electron tomography combined with continuous specimen tilting allows structural analysis of heterogeneous biological specimens. In particular, when combined with a cryo-focused ion beam scanning electron microscope, it becomes possible to directly analyse the structure of the biomolecules within cells, a process known as in situ cryo-electron tomography. This technique has the potential to visualize cytoplasmic zoning, involving liquid-liquid phase separation, caused by biomolecular networks in aqueous solutions, which has been the subject of recent debate. Here, we review advances in structural studies of biomolecules to study cytoplasmic zoning by in situ cryo-electron tomography.
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Affiliation(s)
- Lin Chen
- Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, 38 Nishigonaka, Myodaiji, Okazaki 444-8585, Japan
- National Institute for Physiological Sciences, National Institutes of Natural Sciences, 38 Nishigonaka, Myodaiji, Okazaki 444-8585, Japan
- School of life sciences, Zhejiang Chinese Medical University, No. 548 Binwen Road, Binjiang District, Hangzhou 310053, China
| | - Yuko Fukata
- National Institute for Physiological Sciences, National Institutes of Natural Sciences, 38 Nishigonaka, Myodaiji, Okazaki 444-8585, Japan
- Molecular and Cellular Pharmacology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Kazuyoshi Murata
- Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, 38 Nishigonaka, Myodaiji, Okazaki 444-8585, Japan
- National Institute for Physiological Sciences, National Institutes of Natural Sciences, 38 Nishigonaka, Myodaiji, Okazaki 444-8585, Japan
- Department of Physiological Sciences, School of Life Science, The Graduate University for Advanced Studies (SOKENDAI), 38 Nishigonaka, Myodaiji, Okazaki 444-8585, Japan
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15
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Yao H, Wang X, Chi J, Chen H, Liu Y, Yang J, Yu J, Ruan Y, Xiang X, Pi J, Xu JF. Exploring Novel Antidepressants Targeting G Protein-Coupled Receptors and Key Membrane Receptors Based on Molecular Structures. Molecules 2024; 29:964. [PMID: 38474476 DOI: 10.3390/molecules29050964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 01/29/2024] [Accepted: 02/09/2024] [Indexed: 03/14/2024] Open
Abstract
Major Depressive Disorder (MDD) is a complex mental disorder that involves alterations in signal transmission across multiple scales and structural abnormalities. The development of effective antidepressants (ADs) has been hindered by the dominance of monoamine hypothesis, resulting in slow progress. Traditional ADs have undesirable traits like delayed onset of action, limited efficacy, and severe side effects. Recently, two categories of fast-acting antidepressant compounds have surfaced, dissociative anesthetics S-ketamine and its metabolites, as well as psychedelics such as lysergic acid diethylamide (LSD). This has led to structural research and drug development of the receptors that they target. This review provides breakthroughs and achievements in the structure of depression-related receptors and novel ADs based on these. Cryo-electron microscopy (cryo-EM) has enabled researchers to identify the structures of membrane receptors, including the N-methyl-D-aspartate receptor (NMDAR) and the 5-hydroxytryptamine 2A (5-HT2A) receptor. These high-resolution structures can be used for the development of novel ADs using virtual drug screening (VDS). Moreover, the unique antidepressant effects of 5-HT1A receptors in various brain regions, and the pivotal roles of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) and tyrosine kinase receptor 2 (TrkB) in regulating synaptic plasticity, emphasize their potential as therapeutic targets. Using structural information, a series of highly selective ADs were designed based on the different role of receptors in MDD. These molecules have the favorable characteristics of rapid onset and low adverse drug reactions. This review offers researchers guidance and a methodological framework for the structure-based design of ADs.
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Affiliation(s)
- Hanbo Yao
- Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, The First Dongguan Affiliated Hospital, Guangdong Medical University, Dongguan 523808, China
- Institute of Laboratory Medicine, School of Medical Technology, Guangdong Medical University, Dongguan 523808, China
| | - Xiaodong Wang
- Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, The First Dongguan Affiliated Hospital, Guangdong Medical University, Dongguan 523808, China
- Institute of Laboratory Medicine, School of Medical Technology, Guangdong Medical University, Dongguan 523808, China
| | - Jiaxin Chi
- Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, The First Dongguan Affiliated Hospital, Guangdong Medical University, Dongguan 523808, China
- Institute of Laboratory Medicine, School of Medical Technology, Guangdong Medical University, Dongguan 523808, China
| | - Haorong Chen
- Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, The First Dongguan Affiliated Hospital, Guangdong Medical University, Dongguan 523808, China
- Institute of Laboratory Medicine, School of Medical Technology, Guangdong Medical University, Dongguan 523808, China
| | - Yilin Liu
- Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, The First Dongguan Affiliated Hospital, Guangdong Medical University, Dongguan 523808, China
- Institute of Laboratory Medicine, School of Medical Technology, Guangdong Medical University, Dongguan 523808, China
| | - Jiayi Yang
- Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, The First Dongguan Affiliated Hospital, Guangdong Medical University, Dongguan 523808, China
- Institute of Laboratory Medicine, School of Medical Technology, Guangdong Medical University, Dongguan 523808, China
| | - Jiaqi Yu
- Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, The First Dongguan Affiliated Hospital, Guangdong Medical University, Dongguan 523808, China
- Institute of Laboratory Medicine, School of Medical Technology, Guangdong Medical University, Dongguan 523808, China
| | - Yongdui Ruan
- Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, The First Dongguan Affiliated Hospital, Guangdong Medical University, Dongguan 523808, China
| | - Xufu Xiang
- The Key Laboratory for Biomedical Photonics of MOE at Wuhan National Laboratory for Optoelectronics-Hubei Bioinformatics and Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Jiang Pi
- Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, The First Dongguan Affiliated Hospital, Guangdong Medical University, Dongguan 523808, China
- Institute of Laboratory Medicine, School of Medical Technology, Guangdong Medical University, Dongguan 523808, China
| | - Jun-Fa Xu
- Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, The First Dongguan Affiliated Hospital, Guangdong Medical University, Dongguan 523808, China
- Institute of Laboratory Medicine, School of Medical Technology, Guangdong Medical University, Dongguan 523808, China
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16
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Fan W, Shao K, Luo M. Structural View of Cryo-Electron Microscopy-Determined ATP-Binding Cassette Transporters in Human Multidrug Resistance. Biomolecules 2024; 14:231. [PMID: 38397468 PMCID: PMC10886794 DOI: 10.3390/biom14020231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 02/01/2024] [Accepted: 02/15/2024] [Indexed: 02/25/2024] Open
Abstract
ATP-binding cassette (ABC) transporters, acting as cellular "pumps," facilitate solute translocation through membranes via ATP hydrolysis. Their overexpression is closely tied to multidrug resistance (MDR), a major obstacle in chemotherapy and neurological disorder treatment, hampering drug accumulation and delivery. Extensive research has delved into the intricate interplay between ABC transporter structure, function, and potential inhibition for MDR reversal. Cryo-electron microscopy has been instrumental in unveiling structural details of various MDR-causing ABC transporters, encompassing ABCB1, ABCC1, and ABCG2, as well as the recently revealed ABCC3 and ABCC4 structures. The newly obtained structural insight has deepened our understanding of substrate and drug binding, translocation mechanisms, and inhibitor interactions. Given the growing body of structural information available for human MDR transporters and their associated mechanisms, we believe it is timely to compile a comprehensive review of these transporters and compare their functional mechanisms in the context of multidrug resistance. Therefore, this review primarily focuses on the structural aspects of clinically significant human ABC transporters linked to MDR, with the aim of providing valuable insights to enhance the effectiveness of MDR reversal strategies in clinical therapies.
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Affiliation(s)
| | | | - Min Luo
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore 117543, Singapore; (W.F.); (K.S.)
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17
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Connolly SM, Erwin AL, Sabb M, Hanks JL, Chang L, Torrez RM, Caso GC, Campbell AM, Mosalaganti S, Cover TL, Ohi MD. Structural Analysis of Membrane-associated Forms of Helicobacter pylori VacA Toxin. J Mol Biol 2024; 436:168432. [PMID: 38161000 DOI: 10.1016/j.jmb.2023.168432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 11/27/2023] [Accepted: 12/27/2023] [Indexed: 01/03/2024]
Abstract
Helicobacter pylori colonizes the stomach in about half of the human population, leading to an increased risk of peptic ulcer disease and gastric cancer. H. pylori secretes an 88 kDa VacA toxin that contributes to pathogenesis. VacA assembles into oligomeric complexes in solution and forms anion-selective channels in cell membranes. Cryo-electron microscopy (cryo-EM) analyses of VacA oligomers in solution provided insights into VacA oligomerization but failed to reveal the structure of the hydrophobic N-terminal region predicted to be a pore-forming domain. In this study, we incubated VacA with liposomes and used single particle cryo-EM to analyze detergent-extracted VacA oligomers. A 3D structure of detergent-solubilized VacA hexamers revealed the presence of six α-helices extending from the center of the oligomers, a feature not observed in previous studies of water-soluble VacA oligomers. Cryo-electron tomography analysis and 2D averages of VacA associated with liposomes confirmed that central regions of the membrane-associated VacA oligomers can insert into the lipid bilayer. However, insertion is heterogenous, with some membrane-associated oligomers appearing only partially inserted and others sitting on top of the bilayer. These studies indicate that VacA undergoes a conformational change when contacting the membrane and reveal an α-helical region positioned to extend into the membrane. Although the reported VacA 3D structure does not represent a selective anion channel, our combined single particle 3D analysis, cryo-electron tomography, and modeling allow us to propose a model for the structural organization of the VacA N-terminus in the context of a hexamer as it inserts into the membrane.
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Affiliation(s)
- Sarah M Connolly
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Amanda L Erwin
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA; Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Megan Sabb
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Jessica L Hanks
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Louise Chang
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Rachel M Torrez
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Georgia C Caso
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN, USA; Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Anne M Campbell
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Shyamal Mosalaganti
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA; Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Timothy L Cover
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN, USA; Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN, USA; Veterans Affairs Tennessee Valley Healthcare System, Nashville, TN, USA.
| | - Melanie D Ohi
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA; Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, USA.
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18
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Pfeiffer PB, Ugrina M, Schwierz N, Sigurdson CJ, Schmidt M, Fändrich M. Cryo-EM Analysis of the Effect of Seeding with Brain-derived Aβ Amyloid Fibrils. J Mol Biol 2024; 436:168422. [PMID: 38158175 DOI: 10.1016/j.jmb.2023.168422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 12/05/2023] [Accepted: 12/23/2023] [Indexed: 01/03/2024]
Abstract
Aβ amyloid fibrils from Alzheimer's brain tissue are polymorphic and structurally different from typical in vitro formed Aβ fibrils. Here, we show that brain-derived (ex vivo) fibril structures can be proliferated by seeding in vitro. The proliferation reaction is only efficient for one of the three abundant ex vivo Aβ fibril morphologies, which consists of two peptide stacks, while the inefficiently proliferated fibril morphologies contain four or six peptide stacks. In addition to the seeded fibril structures, we find that de novo nucleated fibril structures can emerge in seeded samples if the seeding reaction is continued over multiple generations. These data imply a competition between de novo nucleation and seed extension and suggest further that seeding favours the outgrowth of fibril morphologies that contain fewer peptide stacks.
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Affiliation(s)
| | - Marijana Ugrina
- Institute of Physics, University of Augsburg, Universitätsstraße 1, 86159 Augsburg, Germany
| | - Nadine Schwierz
- Institute of Physics, University of Augsburg, Universitätsstraße 1, 86159 Augsburg, Germany
| | - Christina J Sigurdson
- Department of Pathology, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0612, USA
| | - Matthias Schmidt
- Institute of Protein Biochemistry, Ulm University, Helmholtzstraße 8/1, 89081 Ulm, Germany
| | - Marcus Fändrich
- Institute of Protein Biochemistry, Ulm University, Helmholtzstraße 8/1, 89081 Ulm, Germany
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19
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Mukherjee A, Kizziah JL, Hawkins NC, Nasef MO, Parker LK, Dokland T. Structure of the Portal Complex from Staphylococcus aureus Pathogenicity Island 1 Transducing Particles In Situ and In Isolation. J Mol Biol 2024; 436:168415. [PMID: 38135177 PMCID: PMC10923094 DOI: 10.1016/j.jmb.2023.168415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 12/15/2023] [Accepted: 12/18/2023] [Indexed: 12/24/2023]
Abstract
Staphylococcus aureus is an important human pathogen, and the prevalence of antibiotic resistance is a major public health concern. The evolution of pathogenicity and resistance in S. aureus often involves acquisition of mobile genetic elements (MGEs). Bacteriophages play an especially important role, since transduction represents the main mechanism for horizontal gene transfer. S. aureus pathogenicity islands (SaPIs), including SaPI1, are MGEs that carry genes encoding virulence factors, and are mobilized at high frequency through interactions with specific "helper" bacteriophages, such as 80α, leading to packaging of the SaPI genomes into virions made from structural proteins supplied by the helper. Among these structural proteins is the portal protein, which forms a ring-like portal at a fivefold vertex of the capsid, through which the DNA is packaged during virion assembly and ejected upon infection of the host. We have used high-resolution cryo-electron microscopy to determine structures of the S. aureus bacteriophage 80α portal itself, produced by overexpression, and in situ in the empty and full SaPI1 virions, and show how the portal interacts with the capsid. These structures provide a basis for understanding portal and capsid assembly and the conformational changes that occur upon DNA packaging and ejection.
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Affiliation(s)
- Amarshi Mukherjee
- Department of Microbiology, The University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - James L Kizziah
- Department of Microbiology, The University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - N'Toia C Hawkins
- Department of Microbiology, The University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Mohamed O Nasef
- Department of Microbiology, The University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Laura K Parker
- Department of Microbiology, The University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Terje Dokland
- Department of Microbiology, The University of Alabama at Birmingham, Birmingham, AL 35294, USA.
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20
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Xu M, Neelands T, Powers AS, Liu Y, Miller SD, Pintilie GD, Bois JD, Dror RO, Chiu W, Maduke M. CryoEM structures of the human CLC-2 voltage-gated chloride channel reveal a ball-and-chain gating mechanism. eLife 2024; 12:RP90648. [PMID: 38345841 PMCID: PMC10942593 DOI: 10.7554/elife.90648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2024] Open
Abstract
CLC-2 is a voltage-gated chloride channel that contributes to electrical excitability and ion homeostasis in many different tissues. Among the nine mammalian CLC homologs, CLC-2 is uniquely activated by hyperpolarization, rather than depolarization, of the plasma membrane. The molecular basis for the divergence in polarity of voltage gating among closely related homologs has been a long-standing mystery, in part because few CLC channel structures are available. Here, we report cryoEM structures of human CLC-2 at 2.46 - 2.76 Å, in the presence and absence of the selective inhibitor AK-42. AK-42 binds within the extracellular entryway of the Cl--permeation pathway, occupying a pocket previously proposed through computational docking studies. In the apo structure, we observed two distinct conformations involving rotation of one of the cytoplasmic C-terminal domains (CTDs). In the absence of CTD rotation, an intracellular N-terminal 15-residue hairpin peptide nestles against the TM domain to physically occlude the Cl--permeation pathway. This peptide is highly conserved among species variants of CLC-2 but is not present in other CLC homologs. Previous studies suggested that the N-terminal domain of CLC-2 influences channel properties via a "ball-and-chain" gating mechanism, but conflicting data cast doubt on such a mechanism, and thus the structure of the N-terminal domain and its interaction with the channel has been uncertain. Through electrophysiological studies of an N-terminal deletion mutant lacking the 15-residue hairpin peptide, we support a model in which the N-terminal hairpin of CLC-2 stabilizes a closed state of the channel by blocking the cytoplasmic Cl--permeation pathway.
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Affiliation(s)
- Mengyuan Xu
- Department of Molecular and Cellular Physiology, Stanford UniversityStanfordUnited States
| | - Torben Neelands
- Department of Molecular and Cellular Physiology, Stanford UniversityStanfordUnited States
| | - Alexander S Powers
- Department of Chemistry, Stanford UniversityStanfordUnited States
- Department of Computer Science, Stanford UniversityStanfordUnited States
- Department of Structural Biology, Stanford UniversityStanfordUnited States
- Institute for Computational and Mathematical Engineering, Stanford UniversityStanfordUnited States
| | - Yan Liu
- Division of CryoEM and Bioimaging, SSRL, SLAC National Accelerator Laboratory, Stanford UniversityStanfordUnited States
| | - Steven D Miller
- Department of Chemistry, Stanford UniversityStanfordUnited States
| | - Grigore D Pintilie
- Department of Bioengineering and Department of Microbiology and Immunology, Stanford UniversityStanfordUnited States
| | - J Du Bois
- Department of Chemistry, Stanford UniversityStanfordUnited States
| | - Ron O Dror
- Department of Molecular and Cellular Physiology, Stanford UniversityStanfordUnited States
- Department of Computer Science, Stanford UniversityStanfordUnited States
- Department of Structural Biology, Stanford UniversityStanfordUnited States
- Institute for Computational and Mathematical Engineering, Stanford UniversityStanfordUnited States
| | - Wah Chiu
- Division of CryoEM and Bioimaging, SSRL, SLAC National Accelerator Laboratory, Stanford UniversityStanfordUnited States
- Department of Bioengineering and Department of Microbiology and Immunology, Stanford UniversityStanfordUnited States
| | - Merritt Maduke
- Department of Molecular and Cellular Physiology, Stanford UniversityStanfordUnited States
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21
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González-Rodríguez N, Areán-Ulloa E, Fernández-Leiro R. A web-based dashboard for RELION metadata visualization. Acta Crystallogr D Struct Biol 2024; 80:93-100. [PMID: 38265874 PMCID: PMC10836394 DOI: 10.1107/s2059798323010902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 12/20/2023] [Indexed: 01/26/2024] Open
Abstract
Cryo-electron microscopy (cryo-EM) has witnessed radical progress in the past decade, driven by developments in hardware and software. While current software packages include processing pipelines that simplify the image-processing workflow, they do not prioritize the in-depth analysis of crucial metadata, limiting troubleshooting for challenging data sets. The widely used RELION software package lacks a graphical native representation of the underlying metadata. Here, two web-based tools are introduced: relion_live.py, which offers real-time feedback on data collection, aiding swift decision-making during data acquisition, and relion_analyse.py, a graphical interface to represent RELION projects by plotting essential metadata including interactive data filtration and analysis. A useful script for estimating ice thickness and data quality during movie pre-processing is also presented. These tools empower researchers to analyse data efficiently and allow informed decisions during data collection and processing.
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Affiliation(s)
- Nayim González-Rodríguez
- Spanish National Cancer Research Centre (CNIO), Melchor Fernández Almagro 3, 28029 Madrid, Spain
| | - Emma Areán-Ulloa
- Spanish National Cancer Research Centre (CNIO), Melchor Fernández Almagro 3, 28029 Madrid, Spain
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, The Netherlands
| | - Rafael Fernández-Leiro
- Spanish National Cancer Research Centre (CNIO), Melchor Fernández Almagro 3, 28029 Madrid, Spain
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22
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Nesterov SV, Plokhikh KS, Chesnokov YM, Mustafin DA, Goleva TN, Rogov AG, Vasilov RG, Yaguzhinsky LS. Safari with an Electron Gun: Visualization of Protein and Membrane Interactions in Mitochondria in Natural Environment. Biochemistry (Mosc) 2024; 89:257-268. [PMID: 38622094 DOI: 10.1134/s0006297924020068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2023] [Revised: 02/06/2024] [Accepted: 02/07/2024] [Indexed: 04/17/2024]
Abstract
This paper presents new structural data about mitochondria using correlative light and electron microscopy (CLEM) and cryo-electron tomography. These state-of-the-art structural biology methods allow studying biological objects at nanometer scales under natural conditions. Non-invasiveness of these methods makes them comparable to observing animals in their natural environment on a safari. The paper highlights two areas of research that can only be accomplished using these methods. The study visualized location of the Aβ42 amyloid aggregates in relation to mitochondria to test a hypothesis of development of mitochondrial dysfunction in Alzheimer's disease. The results showed that the Aβ42 aggregates do not interact with mitochondria, although some of them are closely located. Therefore, the study demonstrated that mitochondrial dysfunction is not directly associated with the effects of aggregates on mitochondrial structure. Other processes should be considered as sources of mitochondrial dysfunction. Second unique area presented in this work is high-resolution visualization of the mitochondrial membranes and proteins in them. Analysis of the cryo-ET data reveals toroidal holes in the lamellar structures of cardiac mitochondrial cristae, where ATP synthases are located. The study proposes a new mechanism for sorting and clustering protein complexes in the membrane based on topology. According to this suggestion, position of the OXPHOS system proteins in the membrane is determined by its curvature. High-resolution tomography expands and complements existing ideas about the structural and functional organization of mitochondria. This makes it possible to study the previously inaccessible structural interactions of proteins with each other and with membranes in vivo.
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Affiliation(s)
- Semen V Nesterov
- National Research Center "Kurchatov Institute", Moscow, 123182, Russia.
| | | | - Yuriy M Chesnokov
- National Research Center "Kurchatov Institute", Moscow, 123182, Russia
| | - Denis A Mustafin
- National Research Center "Kurchatov Institute", Moscow, 123182, Russia
| | - Tatyana N Goleva
- National Research Center "Kurchatov Institute", Moscow, 123182, Russia
| | - Anton G Rogov
- National Research Center "Kurchatov Institute", Moscow, 123182, Russia
| | - Raif G Vasilov
- National Research Center "Kurchatov Institute", Moscow, 123182, Russia
| | - Lev S Yaguzhinsky
- Belozersky Research Institute for Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119992, Russia
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23
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Farci D, Milenkovic S, Iesu L, Tanas M, Ceccarelli M, Piano D. Structural characterization and functional insights into the type II secretion system of the poly-extremophile Deinococcus radiodurans. J Biol Chem 2024; 300:105537. [PMID: 38072042 PMCID: PMC10828601 DOI: 10.1016/j.jbc.2023.105537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 11/07/2023] [Accepted: 11/28/2023] [Indexed: 01/21/2024] Open
Abstract
The extremophile bacterium D. radiodurans boasts a distinctive cell envelope characterized by the regular arrangement of three protein complexes. Among these, the Type II Secretion System (T2SS) stands out as a pivotal structural component. We used cryo-electron microscopy to reveal unique features, such as an unconventional protein belt (DR_1364) around the main secretin (GspD), and a cap (DR_0940) found to be a separated subunit rather than integrated with GspD. Furthermore, a novel region at the N-terminus of the GspD constitutes an additional second gate, supplementing the one typically found in the outer membrane region. This T2SS was found to contribute to envelope integrity, while also playing a role in nucleic acid and nutrient trafficking. Studies on intact cell envelopes show a consistent T2SS structure repetition, highlighting its significance within the cellular framework.
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Affiliation(s)
- Domenica Farci
- Department of Plant Physiology, Warsaw University of Life Sciences - SGGW, Warsaw, Poland; Department of Life and Environmental Sciences, Università degli Studi di Cagliari, Cagliari, Italy; R&D Department, ReGenFix Laboratories, Sardara, Italy.
| | - Stefan Milenkovic
- Department of Physics and IOM/CNR, Università degli Studi di Cagliari, Monserrato, Italy
| | - Luca Iesu
- Department of Life and Environmental Sciences, Università degli Studi di Cagliari, Cagliari, Italy
| | - Marta Tanas
- Department of Life and Environmental Sciences, Università degli Studi di Cagliari, Cagliari, Italy
| | - Matteo Ceccarelli
- Department of Physics and IOM/CNR, Università degli Studi di Cagliari, Monserrato, Italy
| | - Dario Piano
- Department of Plant Physiology, Warsaw University of Life Sciences - SGGW, Warsaw, Poland; Department of Life and Environmental Sciences, Università degli Studi di Cagliari, Cagliari, Italy; R&D Department, ReGenFix Laboratories, Sardara, Italy.
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24
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Adams LJ, Raju S, Ma H, Gilliland T, Reed DS, Klimstra WB, Fremont DH, Diamond MS. Structural and functional basis of VLDLR usage by Eastern equine encephalitis virus. Cell 2024; 187:360-374.e19. [PMID: 38176410 PMCID: PMC10843625 DOI: 10.1016/j.cell.2023.11.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 10/06/2023] [Accepted: 11/28/2023] [Indexed: 01/06/2024]
Abstract
The very-low-density lipoprotein receptor (VLDLR) comprises eight LDLR type A (LA) domains and supports entry of distantly related alphaviruses, including Eastern equine encephalitis virus (EEEV) and Semliki Forest virus (SFV). Here, by resolving multiple cryo-electron microscopy structures of EEEV-VLDLR complexes and performing mutagenesis and functional studies, we show that EEEV uses multiple sites (E1/E2 cleft and E2 A domain) to engage more than one LA domain simultaneously. However, no single LA domain is necessary or sufficient to support efficient EEEV infection. Whereas all EEEV strains show conservation of two VLDLR-binding sites, the EEEV PE-6 strain and a few other EEE complex members feature a single amino acid substitution that enables binding of LA domains to an additional site on the E2 B domain. These structural and functional analyses informed the design of a minimal VLDLR decoy receptor that neutralizes EEEV infection and protects mice from lethal challenge.
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Affiliation(s)
- Lucas J Adams
- Department of Pathology & Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Saravanan Raju
- Department of Pathology & Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Hongming Ma
- Department of Pathology & Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Theron Gilliland
- The Center for Vaccine Research and Department of Immunology, The University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Douglas S Reed
- The Center for Vaccine Research and Department of Immunology, The University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - William B Klimstra
- The Center for Vaccine Research and Department of Immunology, The University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Daved H Fremont
- Department of Pathology & Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Biochemistry & Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA.
| | - Michael S Diamond
- Department of Pathology & Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA; Andrew M. and Jane M. Bursky Center for Human Immunology and Immunotherapy Programs, Washington University School of Medicine, St. Louis, MO 63110, USA; Center for Vaccines and Immunity to Microbial Pathogens, Washington University School of Medicine, St. Louis, MO 63110, USA.
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25
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Gao F, Ye F, Zhang B, Cronin N, Buck M, Zhang X. Structural basis of σ 54 displacement and promoter escape in bacterial transcription. Proc Natl Acad Sci U S A 2024; 121:e2309670120. [PMID: 38170755 PMCID: PMC10786286 DOI: 10.1073/pnas.2309670120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Accepted: 11/17/2023] [Indexed: 01/05/2024] Open
Abstract
Gene transcription is a fundamental cellular process carried out by RNA polymerase (RNAP). Transcription initiation is highly regulated, and in bacteria, transcription initiation is mediated by sigma (σ) factors. σ recruits RNAP to the promoter DNA region, located upstream of the transcription start site (TSS) and facilitates open complex formation, where double-stranded DNA is opened up into a transcription bubble and template strand DNA is positioned inside RNAP for initial RNA synthesis. During initial transcription, RNAP remains bound to σ and upstream DNA, presumably with an enlarging transcription bubble. The release of RNAP from upstream DNA is required for promoter escape and processive transcription elongation. Bacteria sigma factors can be broadly separated into two classes with the majority belonging to the σ70 class, represented by the σ70 that regulates housekeeping genes. σ54 forms a class on its own and regulates stress response genes. Extensive studies on σ70 have revealed the molecular mechanisms of the σ70 dependent process while how σ54 transitions from initial transcription to elongation is currently unknown. Here, we present a series of cryo-electron microscopy structures of the RNAP-σ54 initial transcribing complexes with progressively longer RNA, which reveal structural changes that lead to promoter escape. Our data show that initially, the transcription bubble enlarges, DNA strands scrunch, reducing the interactions between σ54 and DNA strands in the transcription bubble. RNA extension and further DNA scrunching help to release RNAP from σ54 and upstream DNA, enabling the transition to elongation.
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Affiliation(s)
- Forson Gao
- Section of Structural and Synthetic Biology, Department of Infectious Disease, Imperial College London, LondonSW7 2AZ, United Kingdom
| | - Fuzhou Ye
- Section of Structural and Synthetic Biology, Department of Infectious Disease, Imperial College London, LondonSW7 2AZ, United Kingdom
| | - Bowen Zhang
- Section of Structural and Synthetic Biology, Department of Infectious Disease, Imperial College London, LondonSW7 2AZ, United Kingdom
| | - Nora Cronin
- London Consortium for High Resolution cryoEM, the Francis Crick Institute, LondonNW1 1AT, United Kingdom
| | - Martin Buck
- Department of Life Sciences, Imperial College London, LondonSW7 2AZ, United Kingdom
| | - Xiaodong Zhang
- Section of Structural and Synthetic Biology, Department of Infectious Disease, Imperial College London, LondonSW7 2AZ, United Kingdom
- DNA processing machines laboratory, the Francis Crick Institute, LondonNW1 1AT, United Kingdom
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26
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Saunders KO, Counts J, Thakur B, Stalls V, Edwards R, Manne K, Lu X, Mansouri K, Chen Y, Parks R, Barr M, Sutherland L, Bal J, Havill N, Chen H, Machiele E, Jamieson N, Hora B, Kopp M, Janowska K, Anasti K, Jiang C, Van Itallie E, Venkatayogi S, Eaton A, Henderson R, Barbosa C, Alam SM, Santra S, Weissman D, Moody MA, Cain DW, Tam YK, Lewis M, Williams WB, Wiehe K, Montefiori DC, Acharya P, Haynes BF. Vaccine induction of CD4-mimicking HIV-1 broadly neutralizing antibody precursors in macaques. Cell 2024; 187:79-94.e24. [PMID: 38181743 PMCID: PMC10860651 DOI: 10.1016/j.cell.2023.12.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 09/08/2023] [Accepted: 12/01/2023] [Indexed: 01/07/2024]
Abstract
The CD4-binding site (CD4bs) is a conserved epitope on HIV-1 envelope (Env) that can be targeted by protective broadly neutralizing antibodies (bnAbs). HIV-1 vaccines have not elicited CD4bs bnAbs for many reasons, including the occlusion of CD4bs by glycans, expansion of appropriate naive B cells with immunogens, and selection of functional antibody mutations. Here, we demonstrate that immunization of macaques with a CD4bs-targeting immunogen elicits neutralizing bnAb precursors with structural and genetic features of CD4-mimicking bnAbs. Structures of the CD4bs nAb bound to HIV-1 Env demonstrated binding angles and heavy-chain interactions characteristic of all known human CD4-mimicking bnAbs. Macaque nAb were derived from variable and joining gene segments orthologous to the genes of human VH1-46-class bnAb. This vaccine study initiated in primates the B cells from which CD4bs bnAbs can derive, accomplishing the key first step in the development of an effective HIV-1 vaccine.
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Affiliation(s)
- Kevin O Saunders
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA; Department of Surgery, Duke University School of Medicine, Durham, NC 27710, USA; Department of Immunology, Duke University School of Medicine, Durham, NC 27710, USA; Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC 27710, USA.
| | - James Counts
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA; Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Bhishem Thakur
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA; Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Victoria Stalls
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA; Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Robert Edwards
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA; Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Kartik Manne
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA; Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Xiaozhi Lu
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA; Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Katayoun Mansouri
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA; Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Yue Chen
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA; Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Rob Parks
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA; Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Maggie Barr
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA; Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Laura Sutherland
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA; Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Joena Bal
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA; Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Nicholas Havill
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA; Department of Biology, Davidson College, Davidson, NC 28035, USA
| | - Haiyan Chen
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA; Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Emily Machiele
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA; Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Nolan Jamieson
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA; Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Bhavna Hora
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA; Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Megan Kopp
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA; Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Katarzyna Janowska
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA; Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Kara Anasti
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA; Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Chuancang Jiang
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA; Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Elizabeth Van Itallie
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA; Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Sravani Venkatayogi
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA; Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Amanda Eaton
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA; Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Rory Henderson
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA; Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | | | - S Munir Alam
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA; Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Sampa Santra
- Beth Israel Deaconess Medical Center, Boston, MA 02215, USA
| | - Drew Weissman
- Department of Microbiology, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - M Anthony Moody
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA; Department of Pediatrics, Duke University School of Medicine, Durham, NC 27710, USA
| | - Derek W Cain
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA; Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | | | | | - Wilton B Williams
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA; Department of Surgery, Duke University School of Medicine, Durham, NC 27710, USA; Department of Immunology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Kevin Wiehe
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA; Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - David C Montefiori
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA; Department of Surgery, Duke University School of Medicine, Durham, NC 27710, USA
| | - Priyamvada Acharya
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA; Department of Surgery, Duke University School of Medicine, Durham, NC 27710, USA; Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA.
| | - Barton F Haynes
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA; Department of Immunology, Duke University School of Medicine, Durham, NC 27710, USA; Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA.
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27
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Buzzard E, McLaren M, Bragoszewski P, Brancaccio A, Ford H, Daum B, Kuwabara P, Collinson I, Gold V. The consequence of ATP synthase dimer angle on mitochondrial morphology studied by cryo-electron tomography. Biochem J 2024; 481:BCJ20230450. [PMID: 38164968 PMCID: PMC10903453 DOI: 10.1042/bcj20230450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 12/12/2023] [Accepted: 01/02/2024] [Indexed: 01/03/2024]
Abstract
Mitochondrial ATP synthases form rows of dimers, which induce membrane curvature to give cristae their characteristic lamellar or tubular morphology. The angle formed between the central stalks of ATP synthase dimers varies between species. Using cryo-electron tomography and sub-tomogram averaging, we determined the structure of the ATP synthase dimer from the nematode worm C. elegans and show that the dimer angle differs from previously determined structures. The consequences of this species-specific difference at the dimer interface were investigated by comparing C. elegans and S. cerevisiae mitochondrial morphology. We reveal that C. elegans has a larger ATP synthase dimer angle with more lamellar (flatter) cristae when compared to yeast. The underlying cause of this difference was investigated by generating an atomic model of the C. elegans ATP synthase dimer by homology modelling. A comparison of our C. elegans model to an existing S. cerevisiae structure reveals the presence of extensions and rearrangements in C. elegans subunits associated with maintaining the dimer interface. We speculate that increasing dimer angles could provide an advantage for species that inhabit variable-oxygen environments by forming flatter more energetically efficient cristae.
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Affiliation(s)
| | | | - Piotr Bragoszewski
- Instytut Biologii Doswiadczalnej im Marcelego Nenckiego Polskiej Akademii Nauk, Warsaw, Poland
| | | | - Holly Ford
- University of Bristol, Bristol, United Kingdom
| | | | | | | | - Vicki Gold
- University of Exeter, Exeter, United Kingdom
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28
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Lee H, Roh SH. Cryo-EM structures of human DICER dicing a pre-miRNA substrate. FEBS J 2023. [PMID: 38151772 DOI: 10.1111/febs.17048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 12/05/2023] [Accepted: 12/12/2023] [Indexed: 12/29/2023]
Abstract
Dicer, a multi-domain ribonuclease III (RNase III) protein, is crucial for gene regulation via RNA interference. It processes hairpin-like precursors into microRNAs (miRNAs) and long double-stranded RNAs (dsRNAs) into small interfering RNAs (siRNAs). During the "dicing" process, the miRNA or siRNA substrate is stably anchored and cleaved by Dicer's RNase III domain. Although numerous studies have investigated long dsRNA cleavage by Dicer, the specific mechanism by which human Dicer (hDICER) processes pre-miRNA remains unelucidated. This review introduces the recently revealed hDICER structure bound to pre-miRNA uncovered through cryo-electron microscopy and compares it with previous reports describing Dicer. The domain-wise movements of the helicase and dsRNA-binding domain (dsRBD) and specific residues involved in substrate sequence recognition have been identified. During RNA substrate binding, the hDICER apical domains and dsRBD recognize the pre-miRNA termini and cleavage site, respectively. Residue rearrangements in positively charged pockets within the apical domain influence substrate recognition and cleavage site determination. The specific interactions between dsRBD positively charged residues and nucleotide bases near the cleavage site emphasize the significance of cis-acting elements in the hDICER processing mechanism. These findings provide valuable insights for understanding hDICER-related diseases.
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Affiliation(s)
- Hansol Lee
- School of Biological Sciences, Seoul National University, Seoul, South Korea
- Institute of Molecular Biology and Genetics, Seoul National University, Seoul, South Korea
| | - Soung-Hun Roh
- School of Biological Sciences, Seoul National University, Seoul, South Korea
- Institute of Molecular Biology and Genetics, Seoul National University, Seoul, South Korea
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29
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Ellis D, Dosey A, Boyoglu-Barnum S, Park YJ, Gillespie R, Syeda H, Hutchinson GB, Tsybovsky Y, Murphy M, Pettie D, Matheson N, Chan S, Ueda G, Fallas JA, Carter L, Graham BS, Veesler D, Kanekiyo M, King NP. Antigen spacing on protein nanoparticles influences antibody responses to vaccination. Cell Rep 2023; 42:113552. [PMID: 38096058 PMCID: PMC10801709 DOI: 10.1016/j.celrep.2023.113552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 09/28/2023] [Accepted: 11/20/2023] [Indexed: 12/26/2023] Open
Abstract
Immunogen design approaches aim to control the specificity and quality of antibody responses elicited by next-generation vaccines. Here, we use computational protein design to generate a nanoparticle vaccine platform based on the receptor-binding domain (RBD) of influenza hemagglutinin (HA) that enables precise control of antigen conformation and spacing. HA RBDs are presented as either monomers or native-like closed trimers that are connected to the underlying nanoparticle by a rigid linker that is modularly extended to precisely control antigen spacing. Nanoparticle immunogens with decreased spacing between trimeric RBDs elicit antibodies with improved hemagglutination inhibition and neutralization potency as well as binding breadth across diverse H1 HAs. Our "trihead" nanoparticle immunogen platform provides insights into anti-HA immunity, establishes antigen spacing as an important parameter in structure-based vaccine design, and embodies several design features that could be used in next-generation vaccines against influenza and other viruses.
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Affiliation(s)
- Daniel Ellis
- Institute for Protein Design, University of Washington, Seattle, WA 98195, USA; Department of Biochemistry, University of Washington, Seattle, WA 98195, USA; Graduate Program in Molecular and Cellular Biology, University of Washington, Seattle, WA 98195, USA
| | - Annie Dosey
- Institute for Protein Design, University of Washington, Seattle, WA 98195, USA; Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Seyhan Boyoglu-Barnum
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Young-Jun Park
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA; Howard Hughes Medical Institute, Seattle, WA 98195, USA
| | - Rebecca Gillespie
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Hubza Syeda
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Geoffrey B Hutchinson
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Yaroslav Tsybovsky
- Vaccine Research Center Electron Microscopy Unit, Frederick National Laboratory for Cancer Research, Frederick, MD 21701, USA
| | - Michael Murphy
- Institute for Protein Design, University of Washington, Seattle, WA 98195, USA; Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Deleah Pettie
- Institute for Protein Design, University of Washington, Seattle, WA 98195, USA; Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Nick Matheson
- Institute for Protein Design, University of Washington, Seattle, WA 98195, USA; Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Sidney Chan
- Institute for Protein Design, University of Washington, Seattle, WA 98195, USA; Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - George Ueda
- Institute for Protein Design, University of Washington, Seattle, WA 98195, USA; Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Jorge A Fallas
- Institute for Protein Design, University of Washington, Seattle, WA 98195, USA; Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Lauren Carter
- Institute for Protein Design, University of Washington, Seattle, WA 98195, USA; Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Barney S Graham
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - David Veesler
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA; Howard Hughes Medical Institute, Seattle, WA 98195, USA
| | - Masaru Kanekiyo
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Neil P King
- Institute for Protein Design, University of Washington, Seattle, WA 98195, USA; Department of Biochemistry, University of Washington, Seattle, WA 98195, USA.
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Beauvois SG, Flaugnatti N, Ilbert M, Boyer M, Gavello-Fernandez E, Fronzes R, Jurėnas D, Journet L. The tip protein PAAR is required for the function of the type VI secretion system. Microbiol Spectr 2023; 11:e0147823. [PMID: 37800964 PMCID: PMC10715212 DOI: 10.1128/spectrum.01478-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Accepted: 08/09/2023] [Indexed: 10/07/2023] Open
Abstract
IMPORTANCE The type VI secretion system (T6SS) is a bacterial contractile injection system involved in bacterial competition by the delivery of antibacterial toxins. The T6SS consists of an envelope-spanning complex that recruits the baseplate, allowing the polymerization of a contractile tail structure. The tail is a tube wrapped by a sheath and topped by the tip of the system, the VgrG spike/PAAR complex. Effectors loaded onto the puncturing tip or into the tube are propelled in the target cells upon sheath contraction. The PAAR protein tips and sharpens the VgrG spike. However, the importance and the function of this protein remain unclear. Here, we provide evidence for association of PAAR at the tip of the VgrG spike. We also found that the PAAR protein is a T6SS critical component required for baseplate and sheath assembly.
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Affiliation(s)
- Solène G. Beauvois
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie, Bioénergies et Biotechnologie, Institut de Microbiologie de la Méditerranée, Aix-Marseille Université - CNRS UMR7255, Marseille, France
| | - Nicolas Flaugnatti
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie, Bioénergies et Biotechnologie, Institut de Microbiologie de la Méditerranée, Aix-Marseille Université - CNRS UMR7255, Marseille, France
| | - Marianne Ilbert
- Laboratoire de Bioénergétique et Ingénierie des Protéines, Institut de Microbiologie, Bioénergies et Biotechnologie, Institut de Microbiologie de la Méditerranée, Aix-Marseille Université - CNRS UMR7281, Marseille, France
| | - Marie Boyer
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie, Bioénergies et Biotechnologie, Institut de Microbiologie de la Méditerranée, Aix-Marseille Université - CNRS UMR7255, Marseille, France
| | - Esther Gavello-Fernandez
- Institut Européen de Chimie et Biologie, University of Bordeaux, Pessac, France
- CNRS UMR 5234 Microbiologie Fondamentale et Pathogénicité, Bordeaux, France
| | - Rémi Fronzes
- Institut Européen de Chimie et Biologie, University of Bordeaux, Pessac, France
- CNRS UMR 5234 Microbiologie Fondamentale et Pathogénicité, Bordeaux, France
| | - Dukas Jurėnas
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie, Bioénergies et Biotechnologie, Institut de Microbiologie de la Méditerranée, Aix-Marseille Université - CNRS UMR7255, Marseille, France
| | - Laure Journet
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie, Bioénergies et Biotechnologie, Institut de Microbiologie de la Méditerranée, Aix-Marseille Université - CNRS UMR7255, Marseille, France
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31
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Gajbhiye S, Gonzales ED, Toso DB, Kirk NA, Hickey WJ. Identification of NpdA as the protein forming the surface layer in Paracidovorax citrulli and evidence of its occurrence as a surface layer protein in diverse genera of the Betaproteobacteria and Gammaproteobacteria. Access Microbiol 2023; 5:000685.v3. [PMID: 38188235 PMCID: PMC10765051 DOI: 10.1099/acmi.0.000685.v3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 11/13/2023] [Indexed: 01/09/2024] Open
Abstract
The phytopathogen Paracidovorax citrulli possesses an ortholog of a newly identified surface layer protein (SLP) termed NpdA but has not been reported to produce a surface layer (S-layer). This study had two objectives. First, to determine if P. citrulli formed an NpdA-based S-layer and, if so, assess the effects of S-layer formation on virulence, production of nanostructures termed nanopods, and other phenotypes. Second, to establish the distribution of npdA orthologs throughout the Pseudomonadota and examine selected candidate cultures for physical evidence of S-layer formation. Formation of an NpdA-based S-layer by P. citrulli AAC00-1 was confirmed by gene deletion mutagenesis (ΔnpdA), proteomics, and cryo-electron microscopy. There were no significant differences between the wild-type and mutant in virulence assays with detached watermelon fruit. Nanopods contiguous with S-layers of multiple biofilm cells were visualized by transmission electron microscopy. Orthologs of npdA were identified in 62 Betaproteobacteria species and 49 Gammaproteobacteria species. In phylogenetic analyses, NpdA orthologs largely segregated into distinct groups. Cryo-electron microscopy imaging revealed an NpdA-like S-layer in all but one of the 16 additional cultures examined. We conclude that NpdA represents a new family of SLP, forming an S-layer in P. citrulli and other Pseudomonadota. While the S-layer did not contribute to virulence in watermelon fruit, a potential role of the P. citrulli S-layer in another dimension of pathogenesis cannot be ruled out. Lastly, formation of cell-bridging nanopods in biofilms is a new property of S-layers; it remains to be determined if nanopods can mediate intercellular movement of materials.
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Affiliation(s)
- Shabda Gajbhiye
- Department of Bacteriology, University of Wisconsin, Madison, Wisconsin, USA
| | - Erin D Gonzales
- Department of Soil Science, University of Wisconsin, Madison, Wisconsin, USA
| | - Daniel B Toso
- Department of Soil Science, University of Wisconsin, Madison, Wisconsin, USA
- Present address: California Institute for Quantitative Biosciences, University of California, Berkeley, California, USA
| | - Natalie A Kirk
- Department of Soil Science, University of Wisconsin, Madison, Wisconsin, USA
- Present address: Department of Art and Art History, University of Utah, Salt Lake City, Utah, USA
| | - William J Hickey
- Department of Soil Science, University of Wisconsin, Madison, Wisconsin, USA
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32
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Lam AKM, Dutzler R. Mechanistic basis of ligand efficacy in the calcium-activated chloride channel TMEM16A. EMBO J 2023; 42:e115030. [PMID: 37984335 PMCID: PMC10711664 DOI: 10.15252/embj.2023115030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 10/27/2023] [Accepted: 11/02/2023] [Indexed: 11/22/2023] Open
Abstract
Agonist binding in ligand-gated ion channels is coupled to structural rearrangements around the binding site, followed by the opening of the channel pore. In this process, agonist efficacy describes the equilibrium between open and closed conformations in a fully ligand-bound state. Calcium-activated chloride channels in the TMEM16 family are important sensors of intracellular calcium signals and are targets for pharmacological modulators, yet a mechanistic understanding of agonist efficacy has remained elusive. Using a combination of cryo-electron microscopy, electrophysiology, and autocorrelation analysis, we now show that agonist efficacy in the ligand-gated channel TMEM16A is dictated by the conformation of the pore-lining helix α6 around the Ca2+ -binding site. The closure of the binding site, which involves the formation of a π-helix below a hinge region in α6, appears to be coupled to the opening of the inner pore gate, thereby governing the channel's open probability and conductance. Our results provide a mechanism for agonist binding and efficacy and a structural basis for the design of potentiators and partial agonists in the TMEM16 family.
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Affiliation(s)
- Andy KM Lam
- Department of BiochemistryUniversity of ZurichZurichSwitzerland
| | - Raimund Dutzler
- Department of BiochemistryUniversity of ZurichZurichSwitzerland
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33
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Cederfelt D, Badgujar D, Au Musse A, Lohkamp B, Danielson UH, Dobritzsch D. The Allosteric Regulation of Β-Ureidopropionase Depends on Fine-Tuned Stability of Active-Site Loops and Subunit Interfaces. Biomolecules 2023; 13:1763. [PMID: 38136634 PMCID: PMC10741476 DOI: 10.3390/biom13121763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 12/01/2023] [Accepted: 12/05/2023] [Indexed: 12/24/2023] Open
Abstract
The activity of β-ureidopropionase, which catalyses the last step in the degradation of uracil, thymine, and analogous antimetabolites, is cooperatively regulated by the substrate and product of the reaction. This involves shifts in the equilibrium of the oligomeric states of the enzyme, but how these are achieved and result in changes in enzyme catalytic competence has yet to be determined. Here, the regulation of human β-ureidopropionase was further explored via site-directed mutagenesis, inhibition studies, and cryo-electron microscopy. The active-site residue E207, as well as H173 and H307 located at the dimer-dimer interface, are shown to play crucial roles in enzyme activation. Dimer association to larger assemblies requires closure of active-site loops, which positions the catalytically crucial E207 stably in the active site. H173 and H307 likely respond to ligand-induced changes in their environment with changes in their protonation states, which fine-tunes the active-site loop stability and the strength of dimer-dimer interfaces and explains the previously observed pH influence on the oligomer equilibrium. The correlation between substrate analogue structure and effect on enzyme assembly suggests that the ability to favourably interact with F205 may distinguish activators from inhibitors. The cryo-EM structure of human β-ureidopropionase assembly obtained at low pH provides first insights into the architecture of its activated state. and validates our current model of the allosteric regulation mechanism. Closed entrance loop conformations and dimer-dimer interfaces are highly conserved between human and fruit fly enzymes.
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Affiliation(s)
- Daniela Cederfelt
- Department of Chemistry—BMC, Uppsala University, 751 23 Uppsala, Sweden; (D.C.); (D.B.); (U.H.D.)
| | - Dilip Badgujar
- Department of Chemistry—BMC, Uppsala University, 751 23 Uppsala, Sweden; (D.C.); (D.B.); (U.H.D.)
- Department of Cell and Molecular Biology, Uppsala University, 751 23 Uppsala, Sweden
| | - Ayan Au Musse
- Department of Chemistry—BMC, Uppsala University, 751 23 Uppsala, Sweden; (D.C.); (D.B.); (U.H.D.)
- School of Science and Technology, Örebro University, 701 82 Örebro, Sweden
| | - Bernhard Lohkamp
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, 171 77 Stockholm, Sweden;
| | - U. Helena Danielson
- Department of Chemistry—BMC, Uppsala University, 751 23 Uppsala, Sweden; (D.C.); (D.B.); (U.H.D.)
| | - Doreen Dobritzsch
- Department of Chemistry—BMC, Uppsala University, 751 23 Uppsala, Sweden; (D.C.); (D.B.); (U.H.D.)
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34
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Wang X, Ma L, Li N, Gao N. Structural insights into the assembly and mechanism of mpox virus DNA polymerase complex F8-A22-E4-H5. Mol Cell 2023; 83:4398-4412.e4. [PMID: 37995690 DOI: 10.1016/j.molcel.2023.10.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 08/21/2023] [Accepted: 09/25/2023] [Indexed: 11/25/2023]
Abstract
The DNA replication of mpox virus is performed by the viral polymerase F8 and also requires other viral factors, including processivity factor A22, uracil DNA glycosylase E4, and phosphoprotein H5. However, the molecular roles of these viral factors remain unclear. Here, we characterize the structures of F8-A22-E4 and F8-A22-E4-H5 complexes in the presence of different primer-template DNA substrates. E4 is located upstream of F8 on the template single-stranded DNA (ssDNA) and is catalytically active, highlighting a functional coupling between DNA base-excision repair and DNA synthesis. Moreover, H5, in the form of tetramer, binds to the double-stranded DNA (dsDNA) region downstream of F8 in a similar position as PCNA (proliferating cell nuclear antigen) does in eukaryotic polymerase complexes. Omission of H5 or disruption of its DNA interaction showed a reduced synthesis of full-length DNA products. These structures provide snapshots for the working cycle of the polymerase and generate insights into the mechanisms of these essential factors in viral DNA replication.
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Affiliation(s)
- Xiaohan Wang
- State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Center for Life Sciences, School of Life Sciences, Peking University, Beijing 100871, China
| | - Liangwen Ma
- State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Center for Life Sciences, School of Life Sciences, Peking University, Beijing 100871, China; Changping Laboratory, Beijing 102206, China
| | - Ningning Li
- State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Center for Life Sciences, School of Life Sciences, Peking University, Beijing 100871, China; Changping Laboratory, Beijing 102206, China.
| | - Ning Gao
- State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Center for Life Sciences, School of Life Sciences, Peking University, Beijing 100871, China; Changping Laboratory, Beijing 102206, China; National Biomedical Imaging Center, Peking University, Beijing 100871, China.
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35
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Haymaker A, Bardin AA, Gonen T, Martynowycz MW, Nannenga BL. Structure determination of a DNA crystal by MicroED. Structure 2023; 31:1499-1503.e2. [PMID: 37541248 PMCID: PMC10805983 DOI: 10.1016/j.str.2023.07.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 06/21/2023] [Accepted: 07/11/2023] [Indexed: 08/06/2023]
Abstract
Microcrystal electron diffraction (MicroED) is a powerful tool for determining high-resolution structures of microcrystals from a diverse array of biomolecular, chemical, and material samples. In this study, we apply MicroED to DNA crystals, which have not been previously analyzed using this technique. We utilized the d(CGCGCG)2 DNA duplex as a model sample and employed cryo-FIB milling to create thin lamella for diffraction data collection. The MicroED data collection and subsequent processing resulted in a 1.10 Å resolution structure of the d(CGCGCG)2 DNA, demonstrating the successful application of cryo-FIB milling and MicroED to the investigation of nucleic acid crystals.
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Affiliation(s)
- Alison Haymaker
- Biodesign Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, 727 East Tyler Street, Tempe, AZ 85287, USA; School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ, USA
| | - Andrey A Bardin
- Biodesign Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, 727 East Tyler Street, Tempe, AZ 85287, USA; School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ, USA
| | - Tamir Gonen
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Physiology, University of California, Los Angeles, Los Angeles, CA 90095, USA; Howard Hughes Medical Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Michael W Martynowycz
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA.
| | - Brent L Nannenga
- Biodesign Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, 727 East Tyler Street, Tempe, AZ 85287, USA; School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ, USA.
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36
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Abstract
Prestin responds to transmembrane voltage fluctuations by changing its cross-sectional area, a process underlying the electromotility of outer hair cells and cochlear amplification. Prestin belongs to the SLC26 family of anion transporters yet is the only member capable of displaying electromotility. Prestin's voltage-dependent conformational changes are driven by the putative displacement of residue R399 and a set of sparse charged residues within the transmembrane domain, following the binding of a Cl- anion at a conserved binding site formed by the amino termini of the TM3 and TM10 helices. However, a major conundrum arises as to how an anion that binds in proximity to a positive charge (R399), can promote the voltage sensitivity of prestin. Using hydrogen-deuterium exchange mass spectrometry, we find that prestin displays an unstable anion-binding site, where folding of the amino termini of TM3 and TM10 is coupled to Cl- binding. This event shortens the TM3-TM10 electrostatic gap, thereby connecting the two helices, resulting in reduced cross-sectional area. These folding events upon anion binding are absent in SLC26A9, a non-electromotile transporter closely related to prestin. Dynamics of prestin embedded in a lipid bilayer closely match that in detergent micelle, except for a destabilized lipid-facing helix TM6 that is critical to prestin's mechanical expansion. We observe helix fraying at prestin's anion-binding site but cooperative unfolding of multiple lipid-facing helices, features that may promote prestin's fast electromechanical rearrangements. These results highlight a novel role of the folding equilibrium of the anion-binding site, and help define prestin's unique voltage-sensing mechanism and electromotility.
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Affiliation(s)
- Xiaoxuan Lin
- Center for Mechanical Excitability, The University of ChicagoChicagoUnited States
- Department of Biochemistry and Molecular Biology, The University of ChicagoChicagoUnited States
| | - Patrick R Haller
- Center for Mechanical Excitability, The University of ChicagoChicagoUnited States
- Department of Biochemistry and Molecular Biology, The University of ChicagoChicagoUnited States
| | - Navid Bavi
- Center for Mechanical Excitability, The University of ChicagoChicagoUnited States
- Department of Biochemistry and Molecular Biology, The University of ChicagoChicagoUnited States
| | - Nabil Faruk
- Department of Biochemistry and Molecular Biology, The University of ChicagoChicagoUnited States
| | - Eduardo Perozo
- Center for Mechanical Excitability, The University of ChicagoChicagoUnited States
- Department of Biochemistry and Molecular Biology, The University of ChicagoChicagoUnited States
- Institute for Neuroscience, The University of ChicagoChicagoUnited States
- Institute for Biophysical Dynamics, The University of ChicagoChicagoUnited States
| | - Tobin R Sosnick
- Center for Mechanical Excitability, The University of ChicagoChicagoUnited States
- Department of Biochemistry and Molecular Biology, The University of ChicagoChicagoUnited States
- Institute for Biophysical Dynamics, The University of ChicagoChicagoUnited States
- Prizker School for Molecular Engineering, The University of ChicagoChicagoUnited States
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37
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Warmack RA, Rees DC. Nitrogenase beyond the Resting State: A Structural Perspective. Molecules 2023; 28:7952. [PMID: 38138444 PMCID: PMC10745740 DOI: 10.3390/molecules28247952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 11/30/2023] [Accepted: 12/01/2023] [Indexed: 12/24/2023] Open
Abstract
Nitrogenases have the remarkable ability to catalyze the reduction of dinitrogen to ammonia under physiological conditions. How does this happen? The current view of the nitrogenase mechanism focuses on the role of hydrides, the binding of dinitrogen in a reductive elimination process coupled to loss of dihydrogen, and the binding of substrates to a binuclear site on the active site cofactor. This review focuses on recent experimental characterizations of turnover relevant forms of the enzyme determined by cryo-electron microscopy and other approaches, and comparison of these forms to the resting state enzyme and the broader family of iron sulfur clusters. Emerging themes include the following: (i) The obligatory coupling of protein and electron transfers does not occur in synthetic and small-molecule iron-sulfur clusters. The coupling of these processes in nitrogenase suggests that they may involve unique features of the cofactor, such as hydride formation on the trigonal prismatic arrangement of irons, protonation of belt sulfurs, and/or protonation of the interstitial carbon. (ii) Both the active site cofactor and protein are dynamic under turnover conditions; the changes are such that more highly reduced forms may differ in key ways from the resting-state structure. Homocitrate appears to play a key role in coupling cofactor and protein dynamics. (iii) Structural asymmetries are observed in nitrogenase under turnover-relevant conditions by cryo-electron microscopy, although the mechanistic relevance of these states (such as half-of-sites reactivity) remains to be established.
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Affiliation(s)
- Rebeccah A. Warmack
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
- Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA 91125, USA
| | - Douglas C. Rees
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
- Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA 91125, USA
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38
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Zamakhov IM, Anashkin VA, Moiseenko AV, Orlov VN, Vorobyeva NN, Sokolova OS, Baykov AA. The Structure and Nucleotide-Binding Characteristics of Regulated Cystathionine β-Synthase Domain-Containing Pyrophosphatase without One Catalytic Domain. Int J Mol Sci 2023; 24:17160. [PMID: 38138989 PMCID: PMC10742508 DOI: 10.3390/ijms242417160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 11/28/2023] [Accepted: 12/04/2023] [Indexed: 12/24/2023] Open
Abstract
Regulatory adenine nucleotide-binding cystathionine β-synthase (CBS) domains are widespread in proteins; however, information on the mechanism of their modulating effects on protein function is scarce. The difficulty in obtaining structural data for such proteins is ascribed to their unusual flexibility and propensity to form higher-order oligomeric structures. In this study, we deleted the most movable domain from the catalytic part of a CBS domain-containing bacterial inorganic pyrophosphatase (CBS-PPase) and characterized the deletion variant both structurally and functionally. The truncated CBS-PPase was inactive but retained the homotetrameric structure of the full-size enzyme and its ability to bind a fluorescent AMP analog (inhibitor) and diadenosine tetraphosphate (activator) with the same or greater affinity. The deletion stabilized the protein structure against thermal unfolding, suggesting that the deleted domain destabilizes the structure in the full-size protein. A "linear" 3D structure with an unusual type of domain swapping predicted for the truncated CBS-PPase by Alphafold2 was confirmed by single-particle electron microscopy. The results suggest a dual role for the CBS domains in CBS-PPase regulation: they allow for enzyme tetramerization, which impedes the motion of one catalytic domain, and bind adenine nucleotides to mitigate or aggravate this effect.
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Affiliation(s)
- Ilya M. Zamakhov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119899 Moscow, Russia (V.A.A.)
- Department of Chemistry, Lomonosov Moscow State University, 119899 Moscow, Russia
| | - Viktor A. Anashkin
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119899 Moscow, Russia (V.A.A.)
| | - Andrey V. Moiseenko
- Department of Biology, Lomonosov Moscow State University, 119899 Moscow, Russia (O.S.S.)
| | - Victor N. Orlov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119899 Moscow, Russia (V.A.A.)
| | - Natalia N. Vorobyeva
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119899 Moscow, Russia (V.A.A.)
| | - Olga S. Sokolova
- Department of Biology, Lomonosov Moscow State University, 119899 Moscow, Russia (O.S.S.)
- Department of Biology, Shenzhen MSU-BIT University, Shenzhen 518172, China
| | - Alexander A. Baykov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119899 Moscow, Russia (V.A.A.)
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39
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Bogdanović N, Segura-Covarrubias G, Zhang L, Tajima N. Structural dynamics of GluK2 kainate receptors in apo and partial agonist bound states. Res Sq 2023:rs.3.rs-3592604. [PMID: 38076992 PMCID: PMC10705692 DOI: 10.21203/rs.3.rs-3592604/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/22/2023]
Abstract
Kainate receptors (KARs) belong to the family of ionotropic glutamate receptors (iGluRs) and are tetrameric ligand-gated ion channels that regulate neurotransmitter release and excitatory synaptic transmission in the central nervous system. While KARs share overall architectures with other iGluR subfamilies, their dynamics are significantly different from those of other iGluRs. KARs are activated by both full and partial agonists. While there is less efficacy with partial agonists than with full agonists, the detailed mechanism has remained elusive. Here, we used cryo-electron microscopy to determine the structures of homomeric rat GluK2 KARs in the absence of ligands (apo) and in complex with a partial agonist. Intriguingly, the apo state KARs were captured in desensitized conformation. This structure confirms the KAR desensitization prior to activation. Structures of KARs complexed to the partial agonist domoate populate in domoate bound desensitized and non-active/non-desensitized states. These previously unseen intermediate structures highlight the molecular mechanism of partial agonism in KARs. Additionally, we show how N-glycans stabilized the ligand-binding domain dimer via cation/anion binding and modulated receptor gating properties using electrophysiology. Our findings provide vital structural and functional insights into the unique KAR gating mechanisms.
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Affiliation(s)
- Nebojša Bogdanović
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Ohio, 44106, USA
- Equal contribution
| | - Guadalupe Segura-Covarrubias
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Ohio, 44106, USA
- Equal contribution
| | - Lisa Zhang
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Ohio, 44106, USA
| | - Nami Tajima
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Ohio, 44106, USA
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Rosenberg GM, Abskharon R, Boyer DR, Ge P, Sawaya MR, Eisenberg DS. Fibril structures of TFG protein mutants validate the identification of TFG as a disease-related amyloid protein by the IMPAcT method. PNAS Nexus 2023; 2:pgad402. [PMID: 38077690 PMCID: PMC10703350 DOI: 10.1093/pnasnexus/pgad402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 11/13/2023] [Indexed: 12/23/2023]
Abstract
We previously presented a bioinformatic method for identifying diseases that arise from a mutation in a protein's low-complexity domain that drives the protein into pathogenic amyloid fibrils. One protein so identified was the tropomyosin-receptor kinase-fused gene protein (TRK-fused gene protein or TFG). Mutations in TFG are associated with degenerative neurological conditions. Here, we present experimental evidence that confirms our prediction that these conditions are amyloid-related. We find that the low-complexity domain of TFG containing the disease-related mutations G269V or P285L forms amyloid fibrils, and we determine their structures using cryo-electron microscopy (cryo-EM). These structures are unmistakably amyloid in nature and confirm the propensity of the mutant TFG low-complexity domain to form amyloid fibrils. Also, despite resulting from a pathogenic mutation, the fibril structures bear some similarities to other amyloid structures that are thought to be nonpathogenic and even functional, but there are other factors that support these structures' relevance to disease, including an increased propensity to form amyloid compared with the wild-type sequence, structure-stabilizing influence from the mutant residues themselves, and double-protofilament amyloid cores. Our findings elucidate two potentially disease-relevant structures of a previously unknown amyloid and also show how the structural features of pathogenic amyloid fibrils may not conform to the features commonly associated with pathogenicity.
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Affiliation(s)
- Gregory M Rosenberg
- Department of Chemistry and Biochemistry, UCLA-DOE Institute, Molecular Biology Institute, UCLA, Los Angeles, CA 90095, USA
- Department of Biological Chemistry, UCLA-DOE Institute, Molecular Biology Institute, UCLA, Los Angeles, CA 90095, USA
- Howard Hughes Medical Institute, UCLA, Los Angeles, CA 90095, USA
| | - Romany Abskharon
- Department of Chemistry and Biochemistry, UCLA-DOE Institute, Molecular Biology Institute, UCLA, Los Angeles, CA 90095, USA
- Department of Biological Chemistry, UCLA-DOE Institute, Molecular Biology Institute, UCLA, Los Angeles, CA 90095, USA
- Howard Hughes Medical Institute, UCLA, Los Angeles, CA 90095, USA
| | - David R Boyer
- Department of Chemistry and Biochemistry, UCLA-DOE Institute, Molecular Biology Institute, UCLA, Los Angeles, CA 90095, USA
- Department of Biological Chemistry, UCLA-DOE Institute, Molecular Biology Institute, UCLA, Los Angeles, CA 90095, USA
- Howard Hughes Medical Institute, UCLA, Los Angeles, CA 90095, USA
| | - Peng Ge
- Department of Chemistry and Biochemistry, UCLA-DOE Institute, Molecular Biology Institute, UCLA, Los Angeles, CA 90095, USA
- Department of Biological Chemistry, UCLA-DOE Institute, Molecular Biology Institute, UCLA, Los Angeles, CA 90095, USA
- Howard Hughes Medical Institute, UCLA, Los Angeles, CA 90095, USA
| | - Michael R Sawaya
- Department of Chemistry and Biochemistry, UCLA-DOE Institute, Molecular Biology Institute, UCLA, Los Angeles, CA 90095, USA
- Department of Biological Chemistry, UCLA-DOE Institute, Molecular Biology Institute, UCLA, Los Angeles, CA 90095, USA
- Howard Hughes Medical Institute, UCLA, Los Angeles, CA 90095, USA
| | - David S Eisenberg
- Department of Chemistry and Biochemistry, UCLA-DOE Institute, Molecular Biology Institute, UCLA, Los Angeles, CA 90095, USA
- Department of Biological Chemistry, UCLA-DOE Institute, Molecular Biology Institute, UCLA, Los Angeles, CA 90095, USA
- Howard Hughes Medical Institute, UCLA, Los Angeles, CA 90095, USA
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Akatsu M, Ehara H, Kujirai T, Fujita R, Ito T, Osumi K, Ogasawara M, Takizawa Y, Sekine SI, Kurumizaka H. Cryo-EM structures of RNA polymerase II-nucleosome complexes rewrapping transcribed DNA. J Biol Chem 2023; 299:105477. [PMID: 37981206 PMCID: PMC10703601 DOI: 10.1016/j.jbc.2023.105477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 10/30/2023] [Accepted: 11/11/2023] [Indexed: 11/21/2023] Open
Abstract
RNA polymerase II (RNAPII) transcribes DNA wrapped in the nucleosome by stepwise pausing, especially at nucleosomal superhelical locations -5 and -1 [SHL(-5) and SHL(-1), respectively]. In the present study, we performed cryo-electron microscopy analyses of RNAPII-nucleosome complexes paused at a major nucleosomal pausing site, SHL(-1). We determined two previously undetected structures, in which the transcribed DNA behind RNAPII is sharply kinked at the RNAPII exit tunnel and rewrapped around the nucleosomal histones in front of RNAPII by DNA looping. This DNA kink shifts the DNA orientation toward the nucleosome, and the transcribed DNA region interacts with basic amino acid residues of histones H2A, H2B, and H3 exposed by the RNAPII-mediated nucleosomal DNA peeling. The DNA loop structure was not observed in the presence of the transcription elongation factors Spt4/5 and Elf1. These RNAPII-nucleosome structures provide important information for understanding the functional relevance of DNA looping during transcription elongation in the nucleosome.
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Affiliation(s)
- Munetaka Akatsu
- Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo, Tokyo, Japan; Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo, Tokyo, Japan
| | - Haruhiko Ehara
- Laboratory for Transcription Structural Biology, RIKEN Center for Biosystems Dynamics Research, Yokohama, Japan
| | - Tomoya Kujirai
- Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo, Tokyo, Japan; Laboratory for Transcription Structural Biology, RIKEN Center for Biosystems Dynamics Research, Yokohama, Japan
| | - Risa Fujita
- Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo, Tokyo, Japan
| | - Tomoko Ito
- Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo, Tokyo, Japan
| | - Ken Osumi
- Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo, Tokyo, Japan
| | - Mitsuo Ogasawara
- Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo, Tokyo, Japan
| | - Yoshimasa Takizawa
- Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo, Tokyo, Japan
| | - Shun-Ichi Sekine
- Laboratory for Transcription Structural Biology, RIKEN Center for Biosystems Dynamics Research, Yokohama, Japan.
| | - Hitoshi Kurumizaka
- Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo, Tokyo, Japan; Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo, Tokyo, Japan; Laboratory for Transcription Structural Biology, RIKEN Center for Biosystems Dynamics Research, Yokohama, Japan.
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Wakabayashi T, Oide M, Kato T, Nakasako M. Coenzyme-binding pathway on glutamate dehydrogenase suggested from multiple-binding sites visualized by cryo-electron microscopy. FEBS J 2023; 290:5514-5535. [PMID: 37682540 DOI: 10.1111/febs.16951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 08/10/2023] [Accepted: 09/05/2023] [Indexed: 09/09/2023]
Abstract
The structure of hexameric glutamate dehydrogenase (GDH) in the presence of the coenzyme nicotinamide adenine dinucleotide phosphate (NADP) was visualized using cryogenic transmission electron microscopy to investigate the ligand-binding pathways to the active site of the enzyme. Each subunit of GDH comprises one hexamer-forming core domain and one nucleotide-binding domain (NAD domain), which spontaneously opens and closes the active-site cleft situated between the two domains. In the presence of NADP, the potential map of GDH hexamer, assuming D3 symmetry, was determined at a resolution of 2.4 Å, but the NAD domain was blurred due to the conformational variety. After focused classification with respect to the NAD domain, the potential maps interpreted as NADP molecules appeared at five different sites in the active-site cleft. The subunits associated with NADP molecules were close to one of the four metastable conformations in the unliganded state. Three of the five binding sites suggested a pathway of NADP molecules to approach the active-site cleft for initiating the enzymatic reaction. The other two binding modes may rarely appear in the presence of glutamate, as demonstrated by the reaction kinetics. Based on the visualized structures and the results from the enzymatic kinetics, we discussed the binding modes of NADP to GDH in the absence and presence of glutamate.
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Grants
- JPMJPR22E2 Japan Science and Technology Agency
- 18J11653 Japan Society for the Promotion of Science
- jp13480214 Japan Society for the Promotion of Science
- jp19204042 Japan Society for the Promotion of Science
- jp21H01050 Japan Society for the Promotion of Science
- jp22244054 Japan Society for the Promotion of Science
- jp26800227 Japan Society for the Promotion of Science
- jp15076210 Ministry of Education, Culture, Sports, Science and Technology
- jp15H01647 Ministry of Education, Culture, Sports, Science and Technology
- jp17H05891 Ministry of Education, Culture, Sports, Science and Technology
- jp20050030 Ministry of Education, Culture, Sports, Science and Technology
- jp22018027 Ministry of Education, Culture, Sports, Science and Technology
- jp23120525 Ministry of Education, Culture, Sports, Science and Technology
- jp25120725 Ministry of Education, Culture, Sports, Science and Technology
- 0436 Japan Agency for Medical Research and Development
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Affiliation(s)
- Taiki Wakabayashi
- Department of Physics, Faculty of Science and Technology, Keio University, Yokohama, Japan
- RIKEN SPring-8 Center, Sayo-gun, Hyogo, Japan
- RIKEN Cluster for Pioneering Research, Wako, Japan
| | - Mao Oide
- Department of Physics, Faculty of Science and Technology, Keio University, Yokohama, Japan
- RIKEN SPring-8 Center, Sayo-gun, Hyogo, Japan
- RIKEN Cluster for Pioneering Research, Wako, Japan
- PRESTO, Japan Science and Technology Agency, Tokyo, Japan
| | - Takayuki Kato
- Protein Research Institute, Osaka University, Suita, Japan
| | - Masayoshi Nakasako
- Department of Physics, Faculty of Science and Technology, Keio University, Yokohama, Japan
- RIKEN SPring-8 Center, Sayo-gun, Hyogo, Japan
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Xu M, Neelands T, Powers AS, Liu Y, Miller SD, Pintilie G, Bois JD, Dror RO, Chiu W, Maduke M. CryoEM structures of the human CLC-2 voltage gated chloride channel reveal a ball and chain gating mechanism. bioRxiv 2023:2023.08.13.553136. [PMID: 37645939 PMCID: PMC10462068 DOI: 10.1101/2023.08.13.553136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
CLC-2 is a voltage-gated chloride channel that contributes to electrical excitability and ion homeostasis in many different mammalian tissues and cell types. Among the nine mammalian CLC homologs, CLC-2 is uniquely activated by hyperpolarization, rather than depolarization, of the plasma membrane. The molecular basis for the divergence in polarity of voltage gating mechanisms among closely related CLC homologs has been a long-standing mystery, in part because few CLC channel structures are available, and those that exist exhibit high conformational similarity. Here, we report cryoEM structures of human CLC-2 at 2.46 - 2.76 Å, in the presence and absence of the potent and selective inhibitor AK-42. AK-42 binds within the extracellular entryway of the Cl--permeation pathway, occupying a pocket previously proposed through computational docking studies. In the apo structure, we observed two distinct apo conformations of CLC-2 involving rotation of one of the cytoplasmic C-terminal domains (CTDs). In the absence of CTD rotation, an intracellular N-terminal 15-residue hairpin peptide nestles against the TM domain to physically occlude the Cl--permeation pathway from the intracellular side. This peptide is highly conserved among species variants of CLC-2 but is not present in any other CLC homologs. Previous studies suggested that the N-terminal domain of CLC-2 influences channel properties via a "ball-and-chain" gating mechanism, but conflicting data cast doubt on such a mechanism, and thus the structure of the N-terminal domain and its interaction with the channel has been uncertain. Through electrophysiological studies of an N-terminal deletion mutant lacking the 15-residue hairpin peptide, we show that loss of this short sequence increases the magnitude and decreases the rectification of CLC-2 currents expressed in mammalian cells. Furthermore, we show that with repetitive hyperpolarization WT CLC-2 currents increase in resemblance to the hairpin-deleted CLC-2 currents. These functional results combined with our structural data support a model in which the N-terminal hairpin of CLC-2 stabilizes a closed state of the channel by blocking the cytoplasmic Cl--permeation pathway.
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Affiliation(s)
- Mengyuan Xu
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305
| | - Torben Neelands
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305
| | - Alexander S. Powers
- Department of Chemistry, Stanford University, Stanford, CA 94305
- Department of Computer Science, Stanford University, Stanford, CA 94305
- Department of Structural Biology, Stanford University, Stanford, CA 94305
- Institute for Computational and Mathematical Engineering, Stanford University, Stanford, CA 94305
| | - Yan Liu
- Division of CryoEM and Bioimaging, SSRL, SLAC National Accelerator Laboratory, Stanford University, Menlo Park 94025
| | - Steven D. Miller
- Department of Chemistry, Stanford University, Stanford, CA 94305
| | - Grigore Pintilie
- Department of Bioengineering and Department of Microbiology and Immunology, Stanford University, Stanford, 94305
| | - J. Du Bois
- Department of Chemistry, Stanford University, Stanford, CA 94305
| | - Ron O. Dror
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305
- Department of Computer Science, Stanford University, Stanford, CA 94305
- Department of Structural Biology, Stanford University, Stanford, CA 94305
- Institute for Computational and Mathematical Engineering, Stanford University, Stanford, CA 94305
| | - Wah Chiu
- Division of CryoEM and Bioimaging, SSRL, SLAC National Accelerator Laboratory, Stanford University, Menlo Park 94025
- Department of Bioengineering and Department of Microbiology and Immunology, Stanford University, Stanford, 94305
| | - Merritt Maduke
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305
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Norlén L. Molecular Organization of the Skin Barrier. Acta Derm Venereol 2023; 103:adv13356. [PMID: 37987626 PMCID: PMC10680981 DOI: 10.2340/actadv.v103.13356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 10/19/2023] [Indexed: 11/22/2023] Open
Abstract
Cryo-electron microscopy of vitreous sections allows for investigation directly in situ of the molecular architecture of skin. Recently, this technique has contributed to the elucidation of the molecular organization of the skin's permeability barrier and its stepwise formation process. The aim of this review is to provide an overview of the procedure for cryo-electron microscopy of vitreous sections, its analysis using atomic detail molecular dynamics modelling and electron microscopy simulation, and its application in the investigation of the barrier structure and formation process of the skin.
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Affiliation(s)
- Lars Norlén
- Department of Cellular and Molecular Biology (CMB), Karolinska Institutet, Biomedicum, SE-171 77 Stockholm, Sweden.
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45
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Troisi R, Balasco N, Autiero I, Vitagliano L, Sica F. Structural Insights into Protein-Aptamer Recognitions Emerged from Experimental and Computational Studies. Int J Mol Sci 2023; 24:16318. [PMID: 38003510 PMCID: PMC10671752 DOI: 10.3390/ijms242216318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 11/10/2023] [Accepted: 11/12/2023] [Indexed: 11/26/2023] Open
Abstract
Aptamers are synthetic nucleic acids that are developed to target with high affinity and specificity chemical entities ranging from single ions to macromolecules and present a wide range of chemical and physical properties. Their ability to selectively bind proteins has made these compounds very attractive and versatile tools, in both basic and applied sciences, to such an extent that they are considered an appealing alternative to antibodies. Here, by exhaustively surveying the content of the Protein Data Bank (PDB), we review the structural aspects of the protein-aptamer recognition process. As a result of three decades of structural studies, we identified 144 PDB entries containing atomic-level information on protein-aptamer complexes. Interestingly, we found a remarkable increase in the number of determined structures in the last two years as a consequence of the effective application of the cryo-electron microscopy technique to these systems. In the present paper, particular attention is devoted to the articulated architectures that protein-aptamer complexes may exhibit. Moreover, the molecular mechanism of the binding process was analyzed by collecting all available information on the structural transitions that aptamers undergo, from their protein-unbound to the protein-bound state. The contribution of computational approaches in this area is also highlighted.
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Affiliation(s)
- Romualdo Troisi
- Department of Chemical Sciences, University of Naples Federico II, 80126 Naples, Italy;
- Institute of Biostructures and Bioimaging, CNR, 80131 Naples, Italy;
| | - Nicole Balasco
- Institute of Molecular Biology and Pathology, CNR c/o Department of Chemistry, University of Rome Sapienza, 00185 Rome, Italy;
| | - Ida Autiero
- Institute of Biostructures and Bioimaging, CNR, 80131 Naples, Italy;
| | - Luigi Vitagliano
- Institute of Biostructures and Bioimaging, CNR, 80131 Naples, Italy;
| | - Filomena Sica
- Department of Chemical Sciences, University of Naples Federico II, 80126 Naples, Italy;
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Allgood SC, Su CC, Crooks AL, Meyer CT, Zhou B, Betterton MD, Barbachyn MR, Yu EW, Detweiler CS. Bacterial efflux pump modulators prevent bacterial growth in macrophages and under broth conditions that mimic the host environment. mBio 2023; 14:e0249223. [PMID: 37921493 PMCID: PMC10746280 DOI: 10.1128/mbio.02492-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 09/21/2023] [Indexed: 11/04/2023] Open
Abstract
New approaches for combating microbial infections are needed. One strategy for disrupting pathogenesis involves developing compounds that interfere with bacterial virulence. A critical molecular determinant of virulence for Gram-negative bacteria are efflux pumps of the resistance-nodulation-division family, which includes AcrAB-TolC. We previously identified small molecules that bind AcrB, inhibit AcrAB-TolC, and do not appear to damage membranes. These efflux pump modulators (EPMs) were discovered in an in-cell screening platform called SAFIRE (Screen for Anti-infectives using Fluorescence microscopy of IntracellulaR Enterobacteriaceae). SAFIRE identifies compounds that disrupt the growth of a Gram-negative human pathogen, Salmonella enterica serotype Typhimurium (S. Typhimurium), in macrophages. We used medicinal chemistry to iteratively design ~200 EPM35 analogs and test them for activity in SAFIRE, generating compounds with nanomolar potency. Analogs were demonstrated to bind AcrB in a substrate binding pocket by cryo-electron microscopy. Despite having amphipathic structures, the EPM analogs do not disrupt membrane voltage, as monitored by FtsZ localization to the cell septum. The EPM analogs had little effect on bacterial growth in standard Mueller Hinton Broth. However, under broth conditions that mimic the micro-environment of the macrophage phagosome, acrAB is required for growth, the EPM analogs are bacteriostatic, and the EPM analogs increase the potency of antibiotics. These data suggest that under macrophage-like conditions, the EPM analogs prevent the export of a toxic bacterial metabolite(s) through AcrAB-TolC. Thus, compounds that bind AcrB could disrupt infection by specifically interfering with the export of bacterial toxic metabolites, host defense factors, and/or antibiotics.IMPORTANCEBacterial efflux pumps are critical for resistance to antibiotics and for virulence. We previously identified small molecules that inhibit efflux pumps (efflux pump modulators, EPMs) and prevent pathogen replication in host cells. Here, we used medicinal chemistry to increase the activity of the EPMs against pathogens in cells into the nanomolar range. We show by cryo-electron microscopy that these EPMs bind an efflux pump subunit. In broth culture, the EPMs increase the potency (activity), but not the efficacy (maximum effect), of antibiotics. We also found that bacterial exposure to the EPMs appear to enable the accumulation of a toxic metabolite that would otherwise be exported by efflux pumps. Thus, inhibitors of bacterial efflux pumps could interfere with infection not only by potentiating antibiotics, but also by allowing toxic waste products to accumulate within bacteria, providing an explanation for why efflux pumps are needed for virulence in the absence of antibiotics.
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Affiliation(s)
- Samual C. Allgood
- Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, Colorado, USA
| | - Chih-Chia Su
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
- Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
| | - Amy L. Crooks
- Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, Colorado, USA
| | - Christian T. Meyer
- Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, Colorado, USA
- Chemical and Biological Engineering, University of Colorado Boulder, Boulder, Colorado, USA
- Duet Biosystems, Nashville, Tennessee, USA
- Antimicrobial Research Consortium (ARC) Labs, Boulder, Colorado, USA
| | - Bojun Zhou
- Department of Physics, University of Colorado, Boulder, Colorado, USA
| | - Meredith D. Betterton
- Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, Colorado, USA
- Department of Physics, University of Colorado, Boulder, Colorado, USA
- Center for Computational Biology, Flatiron Institute, New York, New York, USA
| | | | - Edward W. Yu
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
- Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
| | - Corrella S. Detweiler
- Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, Colorado, USA
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Meng EC, Goddard TD, Pettersen EF, Couch GS, Pearson ZJ, Morris JH, Ferrin TE. UCSF ChimeraX: Tools for structure building and analysis. Protein Sci 2023; 32:e4792. [PMID: 37774136 PMCID: PMC10588335 DOI: 10.1002/pro.4792] [Citation(s) in RCA: 91] [Impact Index Per Article: 91.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 09/20/2023] [Accepted: 09/23/2023] [Indexed: 10/01/2023]
Abstract
Advances in computational tools for atomic model building are leading to accurate models of large molecular assemblies seen in electron microscopy, often at challenging resolutions of 3-4 Å. We describe new methods in the UCSF ChimeraX molecular modeling package that take advantage of machine-learning structure predictions, provide likelihood-based fitting in maps, and compute per-residue scores to identify modeling errors. Additional model-building tools assist analysis of mutations, post-translational modifications, and interactions with ligands. We present the latest ChimeraX model-building capabilities, including several community-developed extensions. ChimeraX is available free of charge for noncommercial use at https://www.rbvi.ucsf.edu/chimerax.
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Affiliation(s)
- Elaine C. Meng
- Department of Pharmaceutical ChemistryUniversity of California San FranciscoSan FranciscoCaliforniaUSA
| | - Thomas D. Goddard
- Department of Pharmaceutical ChemistryUniversity of California San FranciscoSan FranciscoCaliforniaUSA
| | - Eric F. Pettersen
- Department of Pharmaceutical ChemistryUniversity of California San FranciscoSan FranciscoCaliforniaUSA
| | - Greg S. Couch
- Department of Pharmaceutical ChemistryUniversity of California San FranciscoSan FranciscoCaliforniaUSA
| | - Zach J. Pearson
- Department of Pharmaceutical ChemistryUniversity of California San FranciscoSan FranciscoCaliforniaUSA
| | - John H. Morris
- Department of Pharmaceutical ChemistryUniversity of California San FranciscoSan FranciscoCaliforniaUSA
| | - Thomas E. Ferrin
- Department of Pharmaceutical ChemistryUniversity of California San FranciscoSan FranciscoCaliforniaUSA
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Ahmad M, Jha B, Bose S, Tiwari S, Dwivedy A, Kar D, Pal R, Mariadasse R, Parish T, Jeyakanthan J, Vinothkumar KR, Biswal BK. Structural snapshots of Mycobacterium tuberculosis enolase reveal dual mode of 2PG binding and its implication in enzyme catalysis. IUCrJ 2023; 10:738-753. [PMID: 37860976 PMCID: PMC10619443 DOI: 10.1107/s2052252523008485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 09/27/2023] [Indexed: 10/21/2023]
Abstract
Enolase, a ubiquitous enzyme, catalyzes the reversible conversion of 2-phosphoglycerate (2PG) to phosphoenolpyruvate (PEP) in the glycolytic pathway of organisms of all three domains of life. The underlying mechanism of the 2PG to PEP conversion has been studied in great detail in previous work, however that of the reverse reaction remains to be explored. Here we present structural snapshots of Mycobacterium tuberculosis (Mtb) enolase in apo, PEP-bound and two 2PG-bound forms as it catalyzes the conversion of PEP to 2PG. The two 2PG-bound complex structures differed in the conformation of the bound product (2PG) viz the widely reported canonical conformation and a novel binding pose, which we refer to here as the alternate conformation. Notably, we observed two major differences compared with the forward reaction: the presence of MgB is non-obligatory for the reaction and 2PG assumes an alternate conformation that is likely to facilitate its dissociation from the active site. Molecular dynamics studies and binding free energy calculations further substantiate that the alternate conformation of 2PG causes distortions in both metal ion coordination and hydrogen-bonding interactions, resulting in an increased flexibility of the active-site loops and aiding product release. Taken together, this study presents a probable mechanism involved in PEP to 2PG catalysis that is likely to be mediated by the conformational change of 2PG at the active site.
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Affiliation(s)
- Mohammed Ahmad
- Structural and Functional Biology Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Bhavya Jha
- Structural and Functional Biology Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India
- Department of Zoology, GDM Mahavidyalaya, Patliputra University, Patna 800020, India
| | - Sucharita Bose
- Institute for Stem Cell Science and Regenerative Medicine, Bangalore 560065, India
| | - Satish Tiwari
- Structural and Functional Biology Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Abhisek Dwivedy
- Structural and Functional Biology Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Deepshikha Kar
- Structural and Functional Biology Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Ravikant Pal
- Structural and Functional Biology Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Richard Mariadasse
- Department of Bioinformatics, Alagappa University, Karaikudi, Tamil Nadu 630003, India
| | - Tanya Parish
- Infectious Disease Research Institute, 1616 Eastlake Avenue E, Suite 400, Seattle, WA 98102, USA
- Seattle Children’s Research Institute, Seattle, WA 98109, USA
| | - Jeyaraman Jeyakanthan
- Department of Bioinformatics, Alagappa University, Karaikudi, Tamil Nadu 630003, India
| | - Kutti R. Vinothkumar
- National Centre for Biological Sciences, Tata Institute for Fundamental Research, Bangalore 560065, India
| | - Bichitra Kumar Biswal
- Structural and Functional Biology Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India
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Boulos I, Jabbour J, Khoury S, Mikhael N, Tishkova V, Candoni N, Ghadieh HE, Veesler S, Bassim Y, Azar S, Harb F. Exploring the World of Membrane Proteins: Techniques and Methods for Understanding Structure, Function, and Dynamics. Molecules 2023; 28:7176. [PMID: 37894653 PMCID: PMC10608922 DOI: 10.3390/molecules28207176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 09/13/2023] [Accepted: 10/04/2023] [Indexed: 10/29/2023] Open
Abstract
In eukaryotic cells, membrane proteins play a crucial role. They fall into three categories: intrinsic proteins, extrinsic proteins, and proteins that are essential to the human genome (30% of which is devoted to encoding them). Hydrophobic interactions inside the membrane serve to stabilize integral proteins, which span the lipid bilayer. This review investigates a number of computational and experimental methods used to study membrane proteins. It encompasses a variety of technologies, including electrophoresis, X-ray crystallography, cryogenic electron microscopy (cryo-EM), nuclear magnetic resonance spectroscopy (NMR), biophysical methods, computational methods, and artificial intelligence. The link between structure and function of membrane proteins has been better understood thanks to these approaches, which also hold great promise for future study in the field. The significance of fusing artificial intelligence with experimental data to improve our comprehension of membrane protein biology is also covered in this paper. This effort aims to shed light on the complexity of membrane protein biology by investigating a variety of experimental and computational methods. Overall, the goal of this review is to emphasize how crucial it is to understand the functions of membrane proteins in eukaryotic cells. It gives a general review of the numerous methods used to look into these crucial elements and highlights the demand for multidisciplinary approaches to advance our understanding.
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Affiliation(s)
- Imad Boulos
- Faculty of Medicine and Medical Sciences, University of Balamand, Tripoli P.O. Box 100, Lebanon; (I.B.); (J.J.); (S.K.); (N.M.); (H.E.G.); (Y.B.); (S.A.)
| | - Joy Jabbour
- Faculty of Medicine and Medical Sciences, University of Balamand, Tripoli P.O. Box 100, Lebanon; (I.B.); (J.J.); (S.K.); (N.M.); (H.E.G.); (Y.B.); (S.A.)
| | - Serena Khoury
- Faculty of Medicine and Medical Sciences, University of Balamand, Tripoli P.O. Box 100, Lebanon; (I.B.); (J.J.); (S.K.); (N.M.); (H.E.G.); (Y.B.); (S.A.)
| | - Nehme Mikhael
- Faculty of Medicine and Medical Sciences, University of Balamand, Tripoli P.O. Box 100, Lebanon; (I.B.); (J.J.); (S.K.); (N.M.); (H.E.G.); (Y.B.); (S.A.)
| | - Victoria Tishkova
- CNRS, CINaM (Centre Interdisciplinaire de Nanosciences de Marseille), Campus de Luminy, Case 913, Aix-Marseille University, CEDEX 09, F-13288 Marseille, France; (V.T.); (N.C.); (S.V.)
| | - Nadine Candoni
- CNRS, CINaM (Centre Interdisciplinaire de Nanosciences de Marseille), Campus de Luminy, Case 913, Aix-Marseille University, CEDEX 09, F-13288 Marseille, France; (V.T.); (N.C.); (S.V.)
| | - Hilda E. Ghadieh
- Faculty of Medicine and Medical Sciences, University of Balamand, Tripoli P.O. Box 100, Lebanon; (I.B.); (J.J.); (S.K.); (N.M.); (H.E.G.); (Y.B.); (S.A.)
| | - Stéphane Veesler
- CNRS, CINaM (Centre Interdisciplinaire de Nanosciences de Marseille), Campus de Luminy, Case 913, Aix-Marseille University, CEDEX 09, F-13288 Marseille, France; (V.T.); (N.C.); (S.V.)
| | - Youssef Bassim
- Faculty of Medicine and Medical Sciences, University of Balamand, Tripoli P.O. Box 100, Lebanon; (I.B.); (J.J.); (S.K.); (N.M.); (H.E.G.); (Y.B.); (S.A.)
| | - Sami Azar
- Faculty of Medicine and Medical Sciences, University of Balamand, Tripoli P.O. Box 100, Lebanon; (I.B.); (J.J.); (S.K.); (N.M.); (H.E.G.); (Y.B.); (S.A.)
| | - Frédéric Harb
- Faculty of Medicine and Medical Sciences, University of Balamand, Tripoli P.O. Box 100, Lebanon; (I.B.); (J.J.); (S.K.); (N.M.); (H.E.G.); (Y.B.); (S.A.)
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Kumar I, Paudyal A, Kádková A, Stewart M, Sørensen JB, Radecke J. An Improved Method for Growing Primary Neurons on Electron Microscopy Grids Co-Cultured with Astrocytes. Int J Mol Sci 2023; 24:15191. [PMID: 37894872 PMCID: PMC10606997 DOI: 10.3390/ijms242015191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 10/04/2023] [Accepted: 10/05/2023] [Indexed: 10/29/2023] Open
Abstract
With the increasing popularity of cryo-electron tomography (cryo-ET) in recent years, the quest to establish a method for growing primary neurons directly on electron microscopy grids (EM grids) has been ongoing. Here we describe a straightforward way to establish a mature neuronal network on EM grids, which includes formation of synaptic contacts. These synapses were thin enough to allow for direct visualization of small filaments such as SNARE proteins tethering the synaptic vesicle (SV) to the active zone plasma membrane on a Titan Krios without prior focused ion-beam milling.
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Affiliation(s)
- Ishika Kumar
- Diamond Light Source, Harwell Science and Innovation Campus, Fermi Ave, Didcot OX11 0DE, UK;
| | - Anju Paudyal
- Mary Lyon Centre at MRC Harwell, Harwell Campus, Becquerel Ave, Didcot OX11 ORD, UK; (A.P.); (M.S.)
| | - Anna Kádková
- Department of Neuroscience, University of Copenhagen, Blegdamsvej 3B, DK-2200 Copenhagen, Denmark (J.B.S.)
| | - Michelle Stewart
- Mary Lyon Centre at MRC Harwell, Harwell Campus, Becquerel Ave, Didcot OX11 ORD, UK; (A.P.); (M.S.)
| | - Jakob Balslev Sørensen
- Department of Neuroscience, University of Copenhagen, Blegdamsvej 3B, DK-2200 Copenhagen, Denmark (J.B.S.)
| | - Julika Radecke
- Diamond Light Source, Harwell Science and Innovation Campus, Fermi Ave, Didcot OX11 0DE, UK;
- Department of Neuroscience, University of Copenhagen, Blegdamsvej 3B, DK-2200 Copenhagen, Denmark (J.B.S.)
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