251
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Seffouh A, Trahan C, Wasi T, Jain N, Basu K, Britton RA, Oeffinger M, Ortega J. RbgA ensures the correct timing in the maturation of the 50S subunits functional sites. Nucleic Acids Res 2022; 50:10801-10816. [PMID: 35141754 PMCID: PMC9638911 DOI: 10.1093/nar/gkac059] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Revised: 01/15/2022] [Accepted: 01/26/2022] [Indexed: 11/26/2022] Open
Abstract
RbgA is an essential protein for the assembly of the 50S subunit in Bacillus subtilis. Depletion of RbgA leads to the accumulation of the 45S intermediate. A strain expressing a RbgA variant with reduced GTPase activity generates spontaneous suppressor mutations in uL6. Each suppressor strain accumulates a unique 44S intermediate. We reasoned that characterizing the structure of these mutant 44S intermediates may explain why RbgA is required to catalyze the folding of the 50S functional sites. We found that in the 44S particles, rRNA helices H42 and H97, near the binding site of uL6, adopt a flexible conformation and allow the central protuberance and functional sites in the mutant 44S particles to mature in any order. Instead, the wild-type 45S particles exhibit a stable H42-H97 interaction and their functional sites always mature last. The dependence on RbgA was also less pronounced in the 44S particles. We concluded that the binding of uL6 pauses the maturation of the functional sites, but the central protuberance continues to fold. RbgA exclusively binds intermediates with a formed central protuberance and licenses the folding of the functional sites. Through this mechanism, RbgA ensures that the functional sites of the 50S mature last.
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Affiliation(s)
- Amal Seffouh
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec H3A 0C7, Canada.,Centre for Structural Biology, McGill University, Montreal, Quebec H3G 0B1, Canada
| | - Chirstian Trahan
- Center for genetic and neurological diseases, Institut de Recherches Cliniques de Montréal (IRCM), Montréal, Quebec H2W 1R7, Canada
| | - Tanzila Wasi
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec H3A 0C7, Canada.,Centre for Structural Biology, McGill University, Montreal, Quebec H3G 0B1, Canada
| | - Nikhil Jain
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX 77030, USA.,Center for Metagenomics and Microbiome Research, Baylor College of Medicine, Houston, TX 77030, USA
| | - Kaustuv Basu
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec H3A 0C7, Canada.,Centre for Structural Biology, McGill University, Montreal, Quebec H3G 0B1, Canada
| | - Robert A Britton
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX 77030, USA.,Center for Metagenomics and Microbiome Research, Baylor College of Medicine, Houston, TX 77030, USA
| | - Marlene Oeffinger
- Center for genetic and neurological diseases, Institut de Recherches Cliniques de Montréal (IRCM), Montréal, Quebec H2W 1R7, Canada.,Département de Biochimie et Médecine Moléculaire, Université de Montréal, Montréal, Quebec H3T 1J4, Canada.,Division of Experimental Medicine, McGill University, Montréal, Quebec H4A 3J1, Canada
| | - Joaquin Ortega
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec H3A 0C7, Canada.,Centre for Structural Biology, McGill University, Montreal, Quebec H3G 0B1, Canada
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252
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Yamamori Y, Tomii K. Application of Homology Modeling by Enhanced Profile-Profile Alignment and Flexible-Fitting Simulation to Cryo-EM Based Structure Determination. Int J Mol Sci 2022; 23:1977. [PMID: 35216093 PMCID: PMC8879198 DOI: 10.3390/ijms23041977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 02/07/2022] [Accepted: 02/09/2022] [Indexed: 12/03/2022] Open
Abstract
Application of cryo-electron microscopy (cryo-EM) is crucially important for ascertaining the atomic structure of large biomolecules such as ribosomes and protein complexes in membranes. Advances in cryo-EM technology and software have made it possible to obtain data with near-atomic resolution, but the method is still often capable of producing only a density map with up to medium resolution, either partially or entirely. Therefore, bridging the gap separating the density map and the atomic model is necessary. Herein, we propose a methodology for constructing atomic structure models based on cryo-EM maps with low-to-medium resolution. The method is a combination of sensitive and accurate homology modeling using our profile-profile alignment method with a flexible-fitting method using molecular dynamics simulation. As described herein, this study used benchmark applications to evaluate the model constructions of human two-pore channel 2 (one target protein in CASP13 with its structure determined using cryo-EM data) and the overall structure of Enterococcus hirae V-ATPase complex.
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Affiliation(s)
- Yu Yamamori
- Artificial Intelligence Research Center (AIRC), National Institute of Advanced Industrial Science and Technology (AIST), 2-4-7 Aomi, Koto-ku, Tokyo 135-0064, Japan;
| | - Kentaro Tomii
- Artificial Intelligence Research Center (AIRC), National Institute of Advanced Industrial Science and Technology (AIST), 2-4-7 Aomi, Koto-ku, Tokyo 135-0064, Japan;
- AIST-Tokyo Tech Real World Big-Data Computation Open Innovation Laboratory (RWBC-OIL), National Institute of Advanced Industrial Science and Technology (AIST), 2-4-7 Aomi, Koto-ku, Tokyo 135-0064, Japan
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253
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Mechanisms of inhibition and activation of extrasynaptic αβ GABA A receptors. Nature 2022; 602:529-533. [PMID: 35140402 PMCID: PMC8850191 DOI: 10.1038/s41586-022-04402-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 12/22/2021] [Indexed: 12/21/2022]
Abstract
Type A GABA (γ-aminobutyric acid) receptors represent a diverse population in the mammalian brain, forming pentamers from combinations of α-, β-, γ-, δ-, ε-, ρ-, θ- and π-subunits1. αβ, α4βδ, α6βδ and α5βγ receptors favour extrasynaptic localization, and mediate an essential persistent (tonic) inhibitory conductance in many regions of the mammalian brain1,2. Mutations of these receptors in humans are linked to epilepsy and insomnia3,4. Altered extrasynaptic receptor function is implicated in insomnia, stroke and Angelman and Fragile X syndromes1,5, and drugs targeting these receptors are used to treat postpartum depression6. Tonic GABAergic responses are moderated to avoid excessive suppression of neuronal communication, and can exhibit high sensitivity to Zn2+ blockade, in contrast to synapse-preferring α1βγ, α2βγ and α3βγ receptor responses5,7–12. Here, to resolve these distinctive features, we determined structures of the predominantly extrasynaptic αβ GABAA receptor class. An inhibited state bound by both the lethal paralysing agent α-cobratoxin13 and Zn2+ was used in comparisons with GABA–Zn2+ and GABA-bound structures. Zn2+ nullifies the GABA response by non-competitively plugging the extracellular end of the pore to block chloride conductance. In the absence of Zn2+, the GABA signalling response initially follows the canonical route until it reaches the pore. In contrast to synaptic GABAA receptors, expansion of the midway pore activation gate is limited and it remains closed, reflecting the intrinsic low efficacy that characterizes the extrasynaptic receptor. Overall, this study explains distinct traits adopted by αβ receptors that adapt them to a role in tonic signalling. Cryo-electron microscopy structures are used to identify mechanisms underlying distinct features of extrasynaptic type A γ-aminobutyric acid receptors.
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254
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Cryo-EM structure of transcription termination factor Rho from Mycobacterium tuberculosis reveals bicyclomycin resistance mechanism. Commun Biol 2022; 5:120. [PMID: 35140348 PMCID: PMC8828861 DOI: 10.1038/s42003-022-03069-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 01/21/2022] [Indexed: 01/17/2023] Open
Abstract
The bacterial Rho factor is a ring-shaped motor triggering genome-wide transcription termination and R-loop dissociation. Rho is essential in many species, including in Mycobacterium tuberculosis where rho gene inactivation leads to rapid death. Yet, the M. tuberculosis Rho [MtbRho] factor displays poor NTPase and helicase activities, and resistance to the natural Rho inhibitor bicyclomycin [BCM] that remain unexplained. To address these issues, we solved the cryo-EM structure of MtbRho at 3.3 Å resolution. The MtbRho hexamer is poised into a pre-catalytic, open-ring state wherein specific contacts stabilize ATP in intersubunit ATPase pockets, thereby explaining the cofactor preference of MtbRho. We reveal a leucine-to-methionine substitution that creates a steric bulk in BCM binding cavities near the positions of ATP γ-phosphates, and confers resistance to BCM at the expense of motor efficiency. Our work contributes to explain the unusual features of MtbRho and provides a framework for future antibiotic development. Cryo-EM shows that M. tuberculosis Rho-factor adopts an open, ring-shaped hexamer conformation and a steric bulk in the cavity for bicyclomycin binding, which explains resistance to the antibiotic.
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255
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Saville JW, Mannar D, Zhu X, Srivastava SS, Berezuk AM, Demers JP, Zhou S, Tuttle KS, Sekirov I, Kim A, Li W, Dimitrov DS, Subramaniam S. Structural and biochemical rationale for enhanced spike protein fitness in delta and kappa SARS-CoV-2 variants. Nat Commun 2022; 13:742. [PMID: 35136050 PMCID: PMC8826856 DOI: 10.1038/s41467-022-28324-6] [Citation(s) in RCA: 59] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 01/19/2022] [Indexed: 12/23/2022] Open
Abstract
The Delta and Kappa variants of SARS-CoV-2 co-emerged in India in late 2020, with the Delta variant underlying the resurgence of COVID-19, even in countries with high vaccination rates. In this study, we assess structural and biochemical aspects of viral fitness for these two variants using cryo-electron microscopy (cryo-EM), ACE2-binding and antibody neutralization analyses. Both variants demonstrate escape of antibodies targeting the N-terminal domain, an important immune hotspot for neutralizing epitopes. Compared to wild-type and Kappa lineages, Delta variant spike proteins show modest increase in ACE2 affinity, likely due to enhanced electrostatic complementarity at the RBD-ACE2 interface, which we characterize by cryo-EM. Unexpectedly, Kappa variant spike trimers form a structural head-to-head dimer-of-trimers assembly, which we demonstrate is a result of the E484Q mutation and with unknown biological implications. The combination of increased antibody escape and enhanced ACE2 binding provides an explanation, in part, for the rapid global dominance of the Delta variant.
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Affiliation(s)
- James W Saville
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Dhiraj Mannar
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Xing Zhu
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Shanti S Srivastava
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Alison M Berezuk
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Jean-Philippe Demers
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Steven Zhou
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Katharine S Tuttle
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Inna Sekirov
- BC Centre for Disease Control, Vancouver, BC, V5Z 4R4, Canada
| | - Andrew Kim
- Center for Antibody Therapeutics, Division of Infectious Diseases, Department of Medicine, University of Pittsburgh School of Medicine, 3550 Terrace Str, Pittsburgh, PA, 15261, USA
| | - Wei Li
- Center for Antibody Therapeutics, Division of Infectious Diseases, Department of Medicine, University of Pittsburgh School of Medicine, 3550 Terrace Str, Pittsburgh, PA, 15261, USA
| | - Dimiter S Dimitrov
- Center for Antibody Therapeutics, Division of Infectious Diseases, Department of Medicine, University of Pittsburgh School of Medicine, 3550 Terrace Str, Pittsburgh, PA, 15261, USA
| | - Sriram Subramaniam
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada.
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256
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Simplified quality assessment for small-molecule ligands in the Protein Data Bank. Structure 2022; 30:252-262.e4. [PMID: 35026162 PMCID: PMC8849442 DOI: 10.1016/j.str.2021.10.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 09/14/2021] [Accepted: 10/06/2021] [Indexed: 02/05/2023]
Abstract
More than 70% of the experimentally determined macromolecular structures in the Protein Data Bank (PDB) contain small-molecule ligands. Quality indicators of ∼643,000 ligands present in ∼106,000 PDB X-ray crystal structures have been analyzed. Ligand quality varies greatly with regard to goodness of fit between ligand structure and experimental data, deviations in bond lengths and angles from known chemical structures, and inappropriate interatomic clashes between the ligand and its surroundings. Based on principal component analysis, correlated quality indicators of ligand structure have been aggregated into two largely orthogonal composite indicators measuring goodness of fit to experimental data and deviation from ideal chemical structure. Ranking of the composite quality indicators across the PDB archive enabled construction of uniformly distributed composite ranking score. This score is implemented at RCSB.org to compare chemically identical ligands in distinct PDB structures with easy-to-interpret two-dimensional ligand quality plots, allowing PDB users to quickly assess ligand structure quality and select the best exemplars.
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257
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Joseph AP, Olek M, Malhotra S, Zhang P, Cowtan K, Burnley T, Winn MD. Atomic model validation using the CCP-EM software suite. Acta Crystallogr D Struct Biol 2022; 78:152-161. [PMID: 35102881 PMCID: PMC8805302 DOI: 10.1107/s205979832101278x] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 12/01/2021] [Indexed: 12/02/2022] Open
Abstract
Recently, there has been a dramatic improvement in the quality and quantity of data derived using cryogenic electron microscopy (cryo-EM). This is also associated with a large increase in the number of atomic models built. Although the best resolutions that are achievable are improving, often the local resolution is variable, and a significant majority of data are still resolved at resolutions worse than 3 Å. Model building and refinement is often challenging at these resolutions, and hence atomic model validation becomes even more crucial to identify less reliable regions of the model. Here, a graphical user interface for atomic model validation, implemented in the CCP-EM software suite, is presented. It is aimed to develop this into a platform where users can access multiple complementary validation metrics that work across a range of resolutions and obtain a summary of evaluations. Based on the validation estimates from atomic models associated with cryo-EM structures from SARS-CoV-2, it was observed that models typically favor adopting the most common conformations over fitting the observations when compared with the model agreement with data. At low resolutions, the stereochemical quality may be favored over data fit, but care should be taken to ensure that the model agrees with the data in terms of resolvable features. It is demonstrated that further re-refinement can lead to improvement of the agreement with data without the loss of geometric quality. This also highlights the need for improved resolution-dependent weight optimization in model refinement and an effective test for overfitting that would help to guide the refinement process.
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Affiliation(s)
- Agnel Praveen Joseph
- Scientific Computing Department, Science and Technology Facilities Council, Didcot, United Kingdom
| | - Mateusz Olek
- Department of Chemistry, University of York, York, United Kingdom
- Electron BioImaging Center, Diamond Light Source, Rutherford Appleton Laboratory, Didcot, United Kingdom
| | - Sony Malhotra
- Scientific Computing Department, Science and Technology Facilities Council, Didcot, United Kingdom
| | - Peijun Zhang
- Electron BioImaging Center, Diamond Light Source, Rutherford Appleton Laboratory, Didcot, United Kingdom
| | - Kevin Cowtan
- Department of Chemistry, University of York, York, United Kingdom
| | - Tom Burnley
- Scientific Computing Department, Science and Technology Facilities Council, Didcot, United Kingdom
| | - Martyn D. Winn
- Scientific Computing Department, Science and Technology Facilities Council, Didcot, United Kingdom
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258
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Mi C, Zhang L, Huang G, Shao G, Yang F, You X, Dong MQ, Sun S, Sui SF. Structural basis for assembly of TRAPPII complex and specific activation of GTPase Ypt31/32. SCIENCE ADVANCES 2022; 8:eabi5603. [PMID: 35080977 PMCID: PMC8791620 DOI: 10.1126/sciadv.abi5603] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 12/02/2021] [Indexed: 06/14/2023]
Abstract
Transport protein particle (TRAPP) complexes belong to the multiprotein tethering complex and exist in three forms-core TRAPP/TRAPPI, TRAPPII, and TRAPPIII. TRAPPII activates GTPase Ypt31/Ypt32 as the guanine nucleotide exchange factor in the trans-Golgi network to determine the maturation of Golgi cisternae into post-Golgi carriers in yeast. Here, we present cryo-EM structures of yeast TRAPPII in apo and Ypt32-bound states. All the structures show a dimeric architecture assembled by two triangle-shaped monomers, while the monomer in the apo state exhibits both open and closed conformations, and the monomer in the Ypt32-bound form only captures the closed conformation. Located in the interior of the monomer, Ypt32 binds with both core TRAPP/TRAPPI and Trs120 via its nucleotide-binding domain and binds with Trs31 via its hypervariable domain. Combined with functional analysis, the structures provide insights into the assembly of TRAPPII and the mechanism of the specific activation of Ypt31/Ypt32 by TRAPPII.
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Affiliation(s)
- Chenchen Mi
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Li Zhang
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Guoqiang Huang
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Guangcan Shao
- National Institute of Biological Sciences, Beijing 102206, China
| | - Fan Yang
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Xin You
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Meng-Qiu Dong
- National Institute of Biological Sciences, Beijing 102206, China
| | - Shan Sun
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Sen-Fang Sui
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
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259
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Ross J, McIver Z, Lambert T, Piergentili C, Bird JE, Gallagher KJ, Cruickshank FL, James P, Zarazúa-Arvizu E, Horsfall LE, Waldron KJ, Wilson MD, Mackay CL, Baslé A, Clarke DJ, Marles-Wright J. Pore dynamics and asymmetric cargo loading in an encapsulin nanocompartment. SCIENCE ADVANCES 2022; 8:eabj4461. [PMID: 35080974 PMCID: PMC8791618 DOI: 10.1126/sciadv.abj4461] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 12/02/2021] [Indexed: 06/14/2023]
Abstract
Encapsulins are protein nanocompartments that house various cargo enzymes, including a family of decameric ferritin-like proteins. Here, we study a recombinant Haliangium ochraceum encapsulin:encapsulated ferritin complex using cryo-electron microscopy and hydrogen/deuterium exchange mass spectrometry to gain insight into the structural relationship between the encapsulin shell and its protein cargo. An asymmetric single-particle reconstruction reveals four encapsulated ferritin decamers in a tetrahedral arrangement within the encapsulin nanocompartment. This leads to a symmetry mismatch between the protein cargo and the icosahedral encapsulin shell. The encapsulated ferritin decamers are offset from the interior face of the encapsulin shell. Using hydrogen/deuterium exchange mass spectrometry, we observed the dynamic behavior of the major fivefold pore in the encapsulin shell and show the pore opening via the movement of the encapsulin A-domain. These data will accelerate efforts to engineer the encapsulation of heterologous cargo proteins and to alter the permeability of the encapsulin shell via pore modifications.
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Affiliation(s)
- Jennifer Ross
- EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, UK
- Newcastle University Biosciences Institute, Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Zak McIver
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Thomas Lambert
- EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, UK
| | - Cecilia Piergentili
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Jasmine Emma Bird
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Kelly J. Gallagher
- EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, UK
| | - Faye L. Cruickshank
- EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, UK
| | - Patrick James
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | | | - Louise E. Horsfall
- School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Kevin J. Waldron
- Newcastle University Biosciences Institute, Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Marcus D. Wilson
- Wellcome Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Kings Buildings, Mayfield Road, Edinburgh EH9 3JR, UK
| | - C. Logan Mackay
- EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, UK
| | - Arnaud Baslé
- Newcastle University Biosciences Institute, Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - David J. Clarke
- EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, UK
| | - Jon Marles-Wright
- Newcastle University Biosciences Institute, Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
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260
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Kögel A, Keidel A, Bonneau F, Schäfer IB, Conti E. The human SKI complex regulates channeling of ribosome-bound RNA to the exosome via an intrinsic gatekeeping mechanism. Mol Cell 2022; 82:756-769.e8. [PMID: 35120588 PMCID: PMC8860381 DOI: 10.1016/j.molcel.2022.01.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 12/01/2021] [Accepted: 01/07/2022] [Indexed: 12/31/2022]
Abstract
The superkiller (SKI) complex is the cytoplasmic co-factor and regulator of the RNA-degrading exosome. In human cells, the SKI complex functions mainly in co-translational surveillance-decay pathways, and its malfunction is linked to a severe congenital disorder, the trichohepatoenteric syndrome. To obtain insights into the molecular mechanisms regulating the human SKI (hSKI) complex, we structurally characterized several of its functional states in the context of 80S ribosomes and substrate RNA. In a prehydrolytic ATP form, the hSKI complex exhibits a closed conformation with an inherent gating system that effectively traps the 80S-bound RNA into the hSKI2 helicase subunit. When active, hSKI switches to an open conformation in which the gating is released and the RNA 3′ end exits the helicase. The emerging picture is that the gatekeeping mechanism and architectural remodeling of hSKI underpin a regulated RNA channeling system that is mechanistically conserved among the cytoplasmic and nuclear helicase-exosome complexes. hSKI has closed and open states connected to different helicase conformations The intrinsic closed state traps the RNA 3′ end and blocks the RNA exit path ATP induces the open state of hSKI, allowing 80S ribosome-bound RNA extraction The hSKI open state primes hSKI2 for channeling RNA to the cytosolic exosome
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Affiliation(s)
- Alexander Kögel
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Munich, Germany
| | - Achim Keidel
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Munich, Germany
| | - Fabien Bonneau
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Munich, Germany
| | - Ingmar B Schäfer
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Munich, Germany.
| | - Elena Conti
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Munich, Germany.
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261
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Abstract
The spectacular developments in cryoelectron microscopy involving new cameras, new microscopes, and new software make it possible today to routinely determine the atomic structures of a large range of molecular assemblies. This has allowed us to solve the atomic structure of nanotubes formed from a peptide, Lanreotide. Its gel, Somatuline, is used as a synthetic growth hormone inhibitor in the treatment of both acromegaly and cancers. The self-assembled nanotube results in a slow release form of the peptide, important pharmacologically. The nanotube structure shows an unexpected complexity and highlights the still unpredictable chemical and physicochemical determinants driving peptide self-assembly. Functional and versatile nano- and microassemblies formed by biological molecules are found at all levels of life, from cell organelles to full organisms. Understanding the chemical and physicochemical determinants guiding the formation of these assemblies is crucial not only to understand the biological processes they carry out but also to mimic nature. Among the synthetic peptides forming well-defined nanostructures, the octapeptide Lanreotide has been considered one of the best characterized, in terms of both the atomic structure and its self-assembly process. In the present work, we determined the atomic structure of Lanreotide nanotubes at 2.5-Å resolution by cryoelectron microscopy (cryo-EM). Surprisingly, the asymmetric unit in the nanotube contains eight copies of the peptide, forming two tetramers. There are thus eight different environments for the peptide, and eight different conformations in the nanotube. The structure built from the cryo-EM map is strikingly different from the molecular model, largely based on X-ray fiber diffraction, proposed 20 y ago. Comparison of the nanotube with a crystal structure at 0.83-Å resolution of a Lanreotide derivative highlights the polymorphism for this peptide family. This work shows once again that higher-order assemblies formed by even well-characterized small peptides are very difficult to predict.
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262
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Chen Z, Zhang P, Matsuoka Y, Tsybovsky Y, West K, Santos C, Boyd LF, Nguyen H, Pomerenke A, Stephens T, Olia AS, De Giorgi V, Holbrook MR, Gross R, Postnikova E, Garza NL, Johnson RF, Margulies DH, Kwong PD, Alter HJ, Buchholz UJ, Lusso P, Farci P. Extremely potent monoclonal antibodies neutralize Omicron and other SARS-CoV-2 variants. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2022. [PMID: 35043120 DOI: 10.1101/2022.01.12.22269023] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The ongoing coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has triggered a devastating global health, social and economic crisis. The RNA nature and broad circulation of this virus facilitate the accumulation of mutations, leading to the continuous emergence of variants of concern with increased transmissibility or pathogenicity 1 . This poses a major challenge to the effectiveness of current vaccines and therapeutic antibodies 1, 2 . Thus, there is an urgent need for effective therapeutic and preventive measures with a broad spectrum of action, especially against variants with an unparalleled number of mutations such as the recently emerged Omicron variant, which is rapidly spreading across the globe 3 . Here, we used combinatorial antibody phage-display libraries from convalescent COVID-19 patients to generate monoclonal antibodies against the receptor-binding domain of the SARS-CoV-2 spike protein with ultrapotent neutralizing activity. One such antibody, NE12, neutralizes an early isolate, the WA-1 strain, as well as the Alpha and Delta variants with half-maximal inhibitory concentrations at picomolar level. A second antibody, NA8, has an unusual breadth of neutralization, with picomolar activity against both the Beta and Omicron variants. The prophylactic and therapeutic efficacy of NE12 and NA8 was confirmed in preclinical studies in the golden Syrian hamster model. Analysis by cryo-EM illustrated the structural basis for the neutralization properties of NE12 and NA8. Potent and broadly neutralizing antibodies against conserved regions of the SARS-CoV-2 spike protein may play a key role against future variants of concern that evade immune control.
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263
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Structural transitions in the GTP cap visualized by cryo-electron microscopy of catalytically inactive microtubules. Proc Natl Acad Sci U S A 2022; 119:2114994119. [PMID: 34996871 PMCID: PMC8764682 DOI: 10.1073/pnas.2114994119] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/23/2021] [Indexed: 01/27/2023] Open
Abstract
Microtubules (MTs) are polymers of αβ-tubulin heterodimers that stochastically switch between growth and shrinkage phases. This dynamic instability is critically important for MT function. It is believed that GTP hydrolysis within the MT lattice is accompanied by destabilizing conformational changes and that MT stability depends on a transiently existing GTP cap at the growing MT end. Here, we use cryo-electron microscopy and total internal reflection fluorescence microscopy of GTP hydrolysis-deficient MTs assembled from mutant recombinant human tubulin to investigate the structure of a GTP-bound MT lattice. We find that the GTP-MT lattice of two mutants in which the catalytically active glutamate in α-tubulin was substituted by inactive amino acids (E254A and E254N) is remarkably plastic. Undecorated E254A and E254N MTs with 13 protofilaments both have an expanded lattice but display opposite protofilament twists, making these lattices distinct from the compacted lattice of wild-type GDP-MTs. End-binding proteins of the EB family have the ability to compact both mutant GTP lattices and to stabilize a negative twist, suggesting that they promote this transition also in the GTP cap of wild-type MTs, thereby contributing to the maturation of the MT structure. We also find that the MT seam appears to be stabilized in mutant GTP-MTs and destabilized in GDP-MTs, supporting the proposal that the seam plays an important role in MT stability. Together, these structures of catalytically inactive MTs add mechanistic insight into the GTP state of MTs, the stability of the GTP- and GDP-bound lattice, and our overall understanding of MT dynamic instability.
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264
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Adaixo R, Steiner EM, Righetto RD, Schmidt A, Stahlberg H, Taylor NMI. Cryo-EM structure of native human thyroglobulin. Nat Commun 2022; 13:61. [PMID: 35013249 PMCID: PMC8748809 DOI: 10.1038/s41467-021-27693-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 12/02/2021] [Indexed: 01/26/2023] Open
Abstract
The thyroglobulin (TG) protein is essential to thyroid hormone synthesis, plays a vital role in the regulation of metabolism, development and growth and serves as intraglandular iodine storage. Its architecture is conserved among vertebrates. Synthesis of triiodothyronine (T3) and thyroxine (T4) hormones depends on the conformation, iodination and post-translational modification of TG. Although structural information is available on recombinant and deglycosylated endogenous human thyroglobulin (hTG) from patients with goiters, the structure of native, fully glycosylated hTG remained unknown. Here, we present the cryo-electron microscopy structure of native and fully glycosylated hTG from healthy thyroid glands to 3.2 Å resolution. The structure provides detailed information on hormonogenic and glycosylation sites. We employ liquid chromatography–mass spectrometry (LC-MS) to validate these findings as well as other post-translational modifications and proteolytic cleavage sites. Our results offer insights into thyroid hormonogenesis of native hTG and provide a fundamental understanding of clinically relevant mutations. The iodinated thyroglobulin functions as iodine storage and carrier protein and a precursor for thyroid hormone (TH) biogenesis. Here, the authors report the structure of native, fully glycosylated human thyroglobulin, revealing the location of the hTg hormonogenic and glycosylation sites.
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Affiliation(s)
- Ricardo Adaixo
- Center for Cellular Imaging and NanoAnalytics, Biozentrum, University of Basel, Mattenstrasse 26, 4058, Basel, Switzerland
| | - Eva M Steiner
- Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Blegdamsvej 3B, 2200, Copenhagen, Denmark
| | - Ricardo D Righetto
- Center for Cellular Imaging and NanoAnalytics, Biozentrum, University of Basel, Mattenstrasse 26, 4058, Basel, Switzerland
| | - Alexander Schmidt
- Proteomics Core Facility, Biozentrum, University of Basel, Klingelbergstrasse 72, 4058, Basel, Switzerland
| | - Henning Stahlberg
- Center for Cellular Imaging and NanoAnalytics, Biozentrum, University of Basel, Mattenstrasse 26, 4058, Basel, Switzerland. .,Lab. of Biol. Electron Microscopy, Institute of Physics, SB, EPFL, and Department of Fund. Microbiol., Faculty of Biology and Medicine, UNIL, 1015, Lausanne, Switzerland.
| | - Nicholas M I Taylor
- Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Blegdamsvej 3B, 2200, Copenhagen, Denmark.
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265
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Tsybovsky Y, Sereda V, Golczak M, Krupenko NI, Krupenko SA. Structure of putative tumor suppressor ALDH1L1. Commun Biol 2022; 5:3. [PMID: 35013550 PMCID: PMC8748788 DOI: 10.1038/s42003-021-02963-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 12/10/2021] [Indexed: 11/08/2022] Open
Abstract
Putative tumor suppressor ALDH1L1, the product of natural fusion of three unrelated genes, regulates folate metabolism by catalyzing NADP+-dependent conversion of 10-formyltetrahydrofolate to tetrahydrofolate and CO2. Cryo-EM structures of tetrameric rat ALDH1L1 revealed the architecture and functional domain interactions of this complex enzyme. Highly mobile N-terminal domains, which remove formyl from 10-formyltetrahydrofolate, undergo multiple transient inter-domain interactions. The C-terminal aldehyde dehydrogenase domains, which convert formyl to CO2, form unusually large interfaces with the intermediate domains, homologs of acyl/peptidyl carrier proteins (A/PCPs), which transfer the formyl group between the catalytic domains. The 4'-phosphopantetheine arm of the intermediate domain is fully extended and reaches deep into the catalytic pocket of the C-terminal domain. Remarkably, the tetrameric state of ALDH1L1 is indispensable for catalysis because the intermediate domain transfers formyl between the catalytic domains of different protomers. These findings emphasize the versatility of A/PCPs in complex, highly dynamic enzymatic systems.
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Affiliation(s)
- Yaroslav Tsybovsky
- Cancer Research Technology Program, Leidos Biomedical Research Inc., Frederick National Laboratory for Cancer Research, 8560 Progress Drive, Frederick, MD, 21701, USA.
| | - Valentin Sereda
- Nutrition Research Institute, University of North Carolina at Chapel Hill, 500 Laureate Way, Kannapolis, NC, 28081, USA
| | - Marcin Golczak
- Department of Pharmacology, School of Medicine, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH, 44106, USA
| | - Natalia I Krupenko
- Nutrition Research Institute, University of North Carolina at Chapel Hill, 500 Laureate Way, Kannapolis, NC, 28081, USA
- Department of Nutrition, University of North Carolina at Chapel Hill, 135 Dauer Drive, Chapel Hill, NC, 27599, USA
| | - Sergey A Krupenko
- Nutrition Research Institute, University of North Carolina at Chapel Hill, 500 Laureate Way, Kannapolis, NC, 28081, USA.
- Department of Nutrition, University of North Carolina at Chapel Hill, 135 Dauer Drive, Chapel Hill, NC, 27599, USA.
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266
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Agirrezabala X, Samatova E, Macher M, Liutkute M, Maiti M, Gil-Carton D, Novacek J, Valle M, Rodnina MV. A switch from α-helical to β-strand conformation during co-translational protein folding. EMBO J 2022; 41:e109175. [PMID: 34994471 PMCID: PMC8844987 DOI: 10.15252/embj.2021109175] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Revised: 11/30/2021] [Accepted: 12/06/2021] [Indexed: 11/09/2022] Open
Abstract
Cellular proteins begin to fold as they emerge from the ribosome. The folding landscape of nascent chains is not only shaped by their amino acid sequence but also by the interactions with the ribosome. Here, we combine biophysical methods with cryo‐EM structure determination to show that folding of a β‐barrel protein begins with formation of a dynamic α‐helix inside the ribosome. As the growing peptide reaches the end of the tunnel, the N‐terminal part of the nascent chain refolds to a β‐hairpin structure that remains dynamic until its release from the ribosome. Contacts with the ribosome and structure of the peptidyl transferase center depend on nascent chain conformation. These results indicate that proteins may start out as α‐helices inside the tunnel and switch into their native folds only as they emerge from the ribosome. Moreover, the correlation of nascent chain conformations with reorientation of key residues of the ribosomal peptidyl‐transferase center suggest that protein folding could modulate ribosome activity.
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Affiliation(s)
| | - Ekaterina Samatova
- Department of Physical Biochemistry, Max Planck Institute for Biophysical Chemistry, Gottingen, Germany
| | - Meline Macher
- Department of Physical Biochemistry, Max Planck Institute for Biophysical Chemistry, Gottingen, Germany
| | - Marija Liutkute
- Department of Physical Biochemistry, Max Planck Institute for Biophysical Chemistry, Gottingen, Germany
| | - Manisankar Maiti
- Department of Physical Biochemistry, Max Planck Institute for Biophysical Chemistry, Gottingen, Germany
| | - David Gil-Carton
- CIC bioGUNE, Basque Research and Technology Alliance (BRTA), Derio, Spain.,IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
| | - Jiri Novacek
- CEITEC, Masaryk University, Brno, Czech Republic
| | - Mikel Valle
- CIC bioGUNE, Basque Research and Technology Alliance (BRTA), Derio, Spain
| | - Marina V Rodnina
- Department of Physical Biochemistry, Max Planck Institute for Biophysical Chemistry, Gottingen, Germany
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267
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Nayak AR, Samsó M. Ca 2+ inactivation of the mammalian ryanodine receptor type 1 in a lipidic environment revealed by cryo-EM. eLife 2022; 11:75568. [PMID: 35257661 PMCID: PMC8947763 DOI: 10.7554/elife.75568] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 02/28/2022] [Indexed: 01/07/2023] Open
Abstract
Activation of the intracellular Ca2+ channel ryanodine receptor (RyR) triggers a cytosolic Ca2+ surge, while elevated cytosolic Ca2+ inhibits the channel in a negative feedback mechanism. Cryogenic electron microscopy of rabbit RyR1 embedded in nanodiscs under partially inactivating Ca2+ conditions revealed an open and a closed-inactivated conformation. Ca2+ binding to the high-affinity site engages the central and C-terminal domains into a block, which pries the S6 four-helix bundle open. Further rotation of this block pushes S6 toward the central axis, closing (inactivating) the channel. Main characteristics of the Ca2+-inactivated conformation are downward conformation of the cytoplasmic assembly and tightly knit subunit interface contributed by a fully occupied Ca2+ activation site, two inter-subunit resolved lipids, and two salt bridges between the EF hand domain and the S2-S3 loop validated by disease-causing mutations. The structural insight illustrates the prior Ca2+ activation prerequisite for Ca2+ inactivation and provides for a seamless transition from inactivated to closed conformations.
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Affiliation(s)
- Ashok R Nayak
- Department of Physiology and Biophysics, Virginia Commonwealth UniversityRichmondUnited States
| | - Montserrat Samsó
- Department of Physiology and Biophysics, Virginia Commonwealth UniversityRichmondUnited States
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268
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Peng L, Hu Y, Mankowski MC, Ren P, Chen RE, Wei J, Zhao M, Li T, Tripler T, Ye L, Chow RD, Fang Z, Wu C, Dong MB, Cook M, Wang G, Clark P, Nelson B, Klein D, Sutton R, Diamond MS, Wilen CB, Xiong Y, Chen S. Monospecific and bispecific monoclonal SARS-CoV-2 neutralizing antibodies that maintain potency against B.1.617. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2021:2021.12.21.473733. [PMID: 34981065 PMCID: PMC8722602 DOI: 10.1101/2021.12.21.473733] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
COVID-19 pathogen SARS-CoV-2 has infected hundreds of millions and caused over 5 million deaths to date. Although multiple vaccines are available, breakthrough infections occur especially by emerging variants. Effective therapeutic options such as monoclonal antibodies (mAbs) are still critical. Here, we report the development, cryo-EM structures, and functional analyses of mAbs that potently neutralize SARS-CoV-2 variants of concern. By high-throughput single cell sequencing of B cells from spike receptor binding domain (RBD) immunized animals, we identified two highly potent SARS-CoV-2 neutralizing mAb clones that have single-digit nanomolar affinity and low-picomolar avidity, and generated a bispecific antibody. Lead antibodies showed strong inhibitory activity against historical SARS-CoV-2 and several emerging variants of concern. We solved several cryo-EM structures at ∼3 Å resolution of these neutralizing antibodies in complex with prefusion spike trimer ectodomain, and revealed distinct epitopes, binding patterns, and conformations. The lead clones also showed potent efficacy in vivo against authentic SARS-CoV-2 in both prophylactic and therapeutic settings. We also generated and characterized a humanized antibody to facilitate translation and drug development. The humanized clone also has strong potency against both the original virus and the B.1.617.2 Delta variant. These mAbs expand the repertoire of therapeutics against SARS-CoV-2 and emerging variants.
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Affiliation(s)
- Lei Peng
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA
- System Biology Institute, Yale University, West Haven, CT, USA
- Center for Cancer Systems Biology, Yale University, West Haven, CT, USA
| | - Yingxia Hu
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Madeleine C. Mankowski
- Department of Laboratory Medicine, Yale University, New Haven, CT, USA
- Department of Immunobiology, Yale University, New Haven, CT, USA
| | - Ping Ren
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA
- System Biology Institute, Yale University, West Haven, CT, USA
- Center for Cancer Systems Biology, Yale University, West Haven, CT, USA
| | - Rita E. Chen
- Departments of Medicine and Pathology & Immunology, Washington University School of Medicine in St. Louis, St. Louis, MO, USA
| | - Jin Wei
- Department of Laboratory Medicine, Yale University, New Haven, CT, USA
- Department of Immunobiology, Yale University, New Haven, CT, USA
| | - Min Zhao
- Section of Infectious Diseases, Department of Internal Medicine, Yale University, New Haven, CT, USA
| | - Tongqing Li
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT, USA
- Cancer Biology Institute, Yale University, West Haven, CT, USA
| | - Therese Tripler
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Lupeng Ye
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA
- System Biology Institute, Yale University, West Haven, CT, USA
- Center for Cancer Systems Biology, Yale University, West Haven, CT, USA
| | - Ryan D. Chow
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA
- System Biology Institute, Yale University, West Haven, CT, USA
- Center for Cancer Systems Biology, Yale University, West Haven, CT, USA
- M.D.-Ph.D. Program, Yale University, West Haven, CT, USA
- Molecular Cell Biology, Genetics, and Development Program, Yale University, New Haven, CT, USA
| | - Zhenhao Fang
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA
- System Biology Institute, Yale University, West Haven, CT, USA
- Center for Cancer Systems Biology, Yale University, West Haven, CT, USA
| | - Chunxiang Wu
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Matthew B. Dong
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA
- System Biology Institute, Yale University, West Haven, CT, USA
- Center for Cancer Systems Biology, Yale University, West Haven, CT, USA
- Department of Immunobiology, Yale University, New Haven, CT, USA
- M.D.-Ph.D. Program, Yale University, West Haven, CT, USA
- Immunobiology Program, Yale University, New Haven, CT, USA
| | - Matthew Cook
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Guilin Wang
- Yale Center for Genome Analysis, Yale University, New Haven, CT, USA
| | - Paul Clark
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA
- System Biology Institute, Yale University, West Haven, CT, USA
- Center for Cancer Systems Biology, Yale University, West Haven, CT, USA
| | - Bryce Nelson
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT, USA
- Cancer Biology Institute, Yale University, West Haven, CT, USA
| | - Daryl Klein
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT, USA
- Cancer Biology Institute, Yale University, West Haven, CT, USA
| | - Richard Sutton
- Section of Infectious Diseases, Department of Internal Medicine, Yale University, New Haven, CT, USA
| | - Michael S. Diamond
- Departments of Medicine and Pathology & Immunology, Washington University School of Medicine in St. Louis, St. Louis, MO, USA
- Department of Molecular Microbiology, Washington University School of Medicine in St. Louis, St. Louis, MO, USA
| | - Craig B. Wilen
- Department of Laboratory Medicine, Yale University, New Haven, CT, USA
- Department of Immunobiology, Yale University, New Haven, CT, USA
| | - Yong Xiong
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Sidi Chen
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA
- System Biology Institute, Yale University, West Haven, CT, USA
- Center for Cancer Systems Biology, Yale University, West Haven, CT, USA
- Molecular Cell Biology, Genetics, and Development Program, Yale University, New Haven, CT, USA
- Immunobiology Program, Yale University, New Haven, CT, USA
- Department of Neurosurgery, Yale University School of Medicine, New Haven, CT, USA
- Yale Comprehensive Cancer Center, Yale University School of Medicine, New Haven, CT, USA
- Yale Stem Cell Center, Yale University School of Medicine, New Haven, CT, USA
- Yale Center for Biomedical Data Science, Yale University School of Medicine, New Haven, CT, USA
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269
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Cryo-EM Structures of Two Bacteriophage Portal Proteins Provide Insights for Antimicrobial Phage Engineering. Viruses 2021; 13:v13122532. [PMID: 34960800 PMCID: PMC8703570 DOI: 10.3390/v13122532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 12/07/2021] [Accepted: 12/10/2021] [Indexed: 11/17/2022] Open
Abstract
Widespread antibiotic resistance has returned attention to bacteriophages as a means of managing bacterial pathogenesis. Synthetic biology approaches to engineer phages have demonstrated genomic editing to broaden natural host ranges, or to optimise microbicidal action. Gram positive pathogens cause serious pastoral animal and human infections that are especially lethal in newborns. Such pathogens are targeted by the obligate lytic phages of the Salasmaviridae and Guelinviridae families. These phages have relatively small ~20 kb linear protein-capped genomes and their compact organisation, relatively few structural elements, and broad host range, are appealing from a phage-engineering standpoint. In this study, we focus on portal proteins, which are core elements for the assembly of such tailed phages. The structures of dodecameric portal complexes from Salasmaviridae phage GA1, which targets Bacillus pumilus, and Guelinviridae phage phiCPV4 that infects Clostridium perfringens, were determined at resolutions of 3.3 Å and 2.9 Å, respectively. Both are found to closely resemble the related phi29 portal protein fold. However, the portal protein of phiCPV4 exhibits interesting differences in the clip domain. These structures provide new insights on structural diversity in Caudovirales portal proteins and will be essential for considerations in phage structural engineering.
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270
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Warshamanage R, Yamashita K, Murshudov GN. EMDA: A Python package for Electron Microscopy Data Analysis. J Struct Biol 2021; 214:107826. [PMID: 34915128 PMCID: PMC8935390 DOI: 10.1016/j.jsb.2021.107826] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 12/01/2021] [Accepted: 12/08/2021] [Indexed: 12/01/2022]
Abstract
An open-source Python library EMDA for cryo-EM map and model manipulation is presented with a specific focus on validation. The use of several functionalities in the library is presented through several examples. The utility of local correlation as a metric for identifying map-model differences and unmodeled regions in maps, and how it is used as a metric of map-model validation is demonstrated. The mapping of local correlation to individual atoms, and its use to draw insights on local signal variations are discussed. EMDA’s likelihood-based map overlay is demonstrated by carrying out a superposition of two domains in two related structures. The overlay is carried out first to bring both maps into the same coordinate frame and then to estimate the relative movement of domains. Finally, the map magnification refinement in EMDA is presented with an example to highlight the importance of adjusting the map magnification in structural comparison studies.
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Affiliation(s)
- Rangana Warshamanage
- Structural Studies, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom.
| | - Keitaro Yamashita
- Structural Studies, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom
| | - Garib N Murshudov
- Structural Studies, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom.
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271
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Yan C, Dodd T, Yu J, Leung B, Xu J, Oh J, Wang D, Ivanov I. Mechanism of Rad26-assisted rescue of stalled RNA polymerase II in transcription-coupled repair. Nat Commun 2021; 12:7001. [PMID: 34853308 PMCID: PMC8636621 DOI: 10.1038/s41467-021-27295-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 11/10/2021] [Indexed: 12/22/2022] Open
Abstract
Transcription-coupled repair is essential for the removal of DNA lesions from the transcribed genome. The pathway is initiated by CSB protein binding to stalled RNA polymerase II. Mutations impairing CSB function cause severe genetic disease. Yet, the ATP-dependent mechanism by which CSB powers RNA polymerase to bypass certain lesions while triggering excision of others is incompletely understood. Here we build structural models of RNA polymerase II bound to the yeast CSB ortholog Rad26 in nucleotide-free and bound states. This enables simulations and graph-theoretical analyses to define partitioning of this complex into dynamic communities and delineate how its structural elements function together to remodel DNA. We identify an allosteric pathway coupling motions of the Rad26 ATPase modules to changes in RNA polymerase and DNA to unveil a structural mechanism for CSB-assisted progression past less bulky lesions. Our models allow functional interpretation of the effects of Cockayne syndrome disease mutations.
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Affiliation(s)
- Chunli Yan
- grid.256304.60000 0004 1936 7400Department of Chemistry, Georgia State University, Atlanta, GA USA ,grid.256304.60000 0004 1936 7400Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA USA
| | - Thomas Dodd
- grid.256304.60000 0004 1936 7400Department of Chemistry, Georgia State University, Atlanta, GA USA ,grid.256304.60000 0004 1936 7400Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA USA
| | - Jina Yu
- grid.256304.60000 0004 1936 7400Department of Chemistry, Georgia State University, Atlanta, GA USA ,grid.256304.60000 0004 1936 7400Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA USA
| | - Bernice Leung
- grid.266100.30000 0001 2107 4242Division of Pharmaceutical Sciences, Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093 USA
| | - Jun Xu
- grid.266100.30000 0001 2107 4242Division of Pharmaceutical Sciences, Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093 USA
| | - Juntaek Oh
- grid.266100.30000 0001 2107 4242Division of Pharmaceutical Sciences, Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093 USA
| | - Dong Wang
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California San Diego, La Jolla, CA, 92093, USA. .,Department of Cellular & Molecular Medicine, School of Medicine, University of California San Diego, La Jolla, CA, 92093, USA. .,Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA, 92093, USA.
| | - Ivaylo Ivanov
- Department of Chemistry, Georgia State University, Atlanta, GA, USA. .,Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA, USA.
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272
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Cragnolini T, Kryshtafovych A, Topf M. Cryo-EM targets in CASP14. Proteins 2021; 89:1949-1958. [PMID: 34398978 PMCID: PMC8630773 DOI: 10.1002/prot.26216] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 07/27/2021] [Accepted: 08/06/2021] [Indexed: 11/22/2022]
Abstract
Structures of seven CASP14 targets were determined using cryo-electron microscopy (cryo-EM) technique with resolution between 2.1 and 3.8 Å. We provide an evaluation of the submitted models versus the experimental data (cryo-EM density maps) and experimental reference structures built into the maps. The accuracy of models is measured in terms of coordinate-to-density and coordinate-to-coordinate fit. A-posteriori refinement of the most accurate models in their corresponding cryo-EM density resulted in structures that are close to the reference structure, including some regions with better fit to the density. Regions that were found to be less "refineable" correlate well with regions of high diversity between the CASP models and low goodness-of-fit to density in the reference structure.
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Affiliation(s)
- Tristan Cragnolini
- Institute of Structural and Molecular Biology, Birkbeck, University College London, London, UK
| | | | - Maya Topf
- Center for Structural Systems Biology, Leibniz-Institut für Experimentelle Virologie and Universitätsklinikum Hamburg-Eppendorf (UKE), Hamburg, Germany
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273
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Tüting C, Kyrilis FL, Müller J, Sorokina M, Skalidis I, Hamdi F, Sadian Y, Kastritis PL. Cryo-EM snapshots of a native lysate provide structural insights into a metabolon-embedded transacetylase reaction. Nat Commun 2021; 12:6933. [PMID: 34836937 PMCID: PMC8626477 DOI: 10.1038/s41467-021-27287-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 11/08/2021] [Indexed: 11/23/2022] Open
Abstract
Found across all kingdoms of life, 2-keto acid dehydrogenase complexes possess prominent metabolic roles and form major regulatory sites. Although their component structures are known, their higher-order organization is highly heterogeneous, not only across species or tissues but also even within a single cell. Here, we report a cryo-EM structure of the fully active Chaetomium thermophilum pyruvate dehydrogenase complex (PDHc) core scaffold at 3.85 Å resolution (FSC = 0.143) from native cell extracts. By combining cryo-EM with macromolecular docking and molecular dynamics simulations, we resolve all PDHc core scaffold interfaces and dissect the residing transacetylase reaction. Electrostatics attract the lipoyl domain to the transacetylase active site and stabilize the coenzyme A, while apolar interactions position the lipoate in its binding cleft. Our results have direct implications on the structural determinants of the transacetylase reaction and the role of flexible regions in the context of the overall 10 MDa PDHc metabolon architecture.
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Affiliation(s)
- Christian Tüting
- Interdisciplinary Research Center HALOmem, Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Straße 3a, Halle/Saale, Germany
| | - Fotis L Kyrilis
- Interdisciplinary Research Center HALOmem, Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Straße 3a, Halle/Saale, Germany
- Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Straße 3, Halle/Saale, Germany
| | - Johannes Müller
- Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Straße 3, Halle/Saale, Germany
| | - Marija Sorokina
- Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Straße 3, Halle/Saale, Germany
- RGCC International GmbH, Baarerstrasse 95, Zug, 6300, Switzerland
- BioSolutions GmbH Weinbergweg 22, 06120, Halle/Saale, Germany
| | - Ioannis Skalidis
- Interdisciplinary Research Center HALOmem, Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Straße 3a, Halle/Saale, Germany
- Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Straße 3, Halle/Saale, Germany
| | - Farzad Hamdi
- Interdisciplinary Research Center HALOmem, Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Straße 3a, Halle/Saale, Germany
| | - Yashar Sadian
- Bioimaging Center (cryoGEnic), Université de Genève, Sciences II, 1211, Genève 4, Switzerland
| | - Panagiotis L Kastritis
- Interdisciplinary Research Center HALOmem, Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Straße 3a, Halle/Saale, Germany.
- Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Straße 3, Halle/Saale, Germany.
- Biozentrum, Martin Luther University Halle-Wittenberg, Weinbergweg 22, Halle/Saale, Germany.
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274
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Montgomery MG, Petri J, Spikes TE, Walker JE. Structure of the ATP synthase from Mycobacterium smegmatis provides targets for treating tuberculosis. Proc Natl Acad Sci U S A 2021; 118:e2111899118. [PMID: 34782468 PMCID: PMC8617483 DOI: 10.1073/pnas.2111899118] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 10/13/2021] [Indexed: 01/01/2023] Open
Abstract
The structure has been determined by electron cryomicroscopy of the adenosine triphosphate (ATP) synthase from Mycobacterium smegmatis This analysis confirms features in a prior description of the structure of the enzyme, but it also describes other highly significant attributes not recognized before that are crucial for understanding the mechanism and regulation of the mycobacterial enzyme. First, we resolved not only the three main states in the catalytic cycle described before but also eight substates that portray structural and mechanistic changes occurring during a 360° catalytic cycle. Second, a mechanism of auto-inhibition of ATP hydrolysis involves not only the engagement of the C-terminal region of an α-subunit in a loop in the γ-subunit, as proposed before, but also a "fail-safe" mechanism involving the b'-subunit in the peripheral stalk that enhances engagement. A third unreported characteristic is that the fused bδ-subunit contains a duplicated domain in its N-terminal region where the two copies of the domain participate in similar modes of attachment of the two of three N-terminal regions of the α-subunits. The auto-inhibitory plus the associated "fail-safe" mechanisms and the modes of attachment of the α-subunits provide targets for development of innovative antitubercular drugs. The structure also provides support for an observation made in the bovine ATP synthase that the transmembrane proton-motive force that provides the energy to drive the rotary mechanism is delivered directly and tangentially to the rotor via a Grotthuss water chain in a polar L-shaped tunnel.
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Affiliation(s)
- Martin G Montgomery
- The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, United Kingdom
| | - Jessica Petri
- The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, United Kingdom
| | - Tobias E Spikes
- The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, United Kingdom
| | - John E Walker
- The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, United Kingdom
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275
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Chrustowicz J, Sherpa D, Teyra J, Loke MS, Popowicz GM, Basquin J, Sattler M, Prabu JR, Sidhu SS, Schulman BA. Multifaceted N-Degron Recognition and Ubiquitylation by GID/CTLH E3 Ligases. J Mol Biol 2021; 434:167347. [PMID: 34767800 DOI: 10.1016/j.jmb.2021.167347] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 11/02/2021] [Accepted: 11/02/2021] [Indexed: 12/22/2022]
Abstract
N-degron E3 ubiquitin ligases recognize specific residues at the N-termini of substrates. Although molecular details of N-degron recognition are known for several E3 ligases, the range of N-terminal motifs that can bind a given E3 substrate binding domain remains unclear. Here, we discovered capacity of Gid4 and Gid10 substrate receptor subunits of yeast "GID"/human "CTLH" multiprotein E3 ligases to tightly bind a wide range of N-terminal residues whose recognition is determined in part by the downstream sequence context. Screening of phage displaying peptide libraries with exposed N-termini identified novel consensus motifs with non-Pro N-terminal residues binding Gid4 or Gid10 with high affinity. Structural data reveal that conformations of flexible loops in Gid4 and Gid10 complement sequences and folds of interacting peptides. Together with analysis of endogenous substrate degrons, the data show that degron identity, substrate domains harboring targeted lysines, and varying E3 ligase higher-order assemblies combinatorially determine efficiency of ubiquitylation and degradation.
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Affiliation(s)
- Jakub Chrustowicz
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany. https://twitter.com/chrustowicz_j
| | - Dawafuti Sherpa
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany. https://twitter.com/dawafutisherpa
| | - Joan Teyra
- The Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada
| | - Mun Siong Loke
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Grzegorz M Popowicz
- Helmholtz Zentrum München, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany; Bavarian NMR Center, Department of Chemistry, Technical University of Munich, Germany
| | - Jerome Basquin
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Michael Sattler
- Helmholtz Zentrum München, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany; Bavarian NMR Center, Department of Chemistry, Technical University of Munich, Germany
| | - J Rajan Prabu
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany. https://twitter.com/rajanprabu
| | - Sachdev S Sidhu
- The Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Brenda A Schulman
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany.
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276
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Cryo-EM structures of PI3Kα reveal conformational changes during inhibition and activation. Proc Natl Acad Sci U S A 2021; 118:2109327118. [PMID: 34725156 PMCID: PMC8609346 DOI: 10.1073/pnas.2109327118] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/13/2021] [Indexed: 02/07/2023] Open
Abstract
Phosphoinositide 3-kinases (PI3Ks) are of critical importance in cell signaling and can function as drivers of disease. Information on the PI3K structure is essential for an understanding of the function of these proteins and for the identification of specific and effective small-molecule inhibitors. Here we present a single-particle cryo-electron microscopy (cryo-EM) analysis of PI3Kα, the dimer consisting of the p110α catalytic subunit bound to the p85α regulatory subunit. We investigated three conformational states of PI3Kα: the unbound dimer, the dimer bound to the isoform-specific inhibitor BYL-719, and the dimer associated with an activating phosphopeptide. Each of these conformations reveals specific structural features that provide insights into conformation-associated functions. Phosphoinositide 3-kinases (PI3Ks) are lipid kinases essential for growth and metabolism. Their aberrant activation is associated with many types of cancers. Here we used single-particle cryoelectron microscopy (cryo-EM) to determine three distinct conformations of full-length PI3Kα (p110α–p85α): the unliganded heterodimer PI3Kα, PI3Kα bound to the p110α-specific inhibitor BYL-719, and PI3Kα exposed to an activating phosphopeptide. The cryo-EM structures of unbound and of BYL-719–bound PI3Kα are in general accord with published crystal structures. Local deviations are presented and discussed. BYL-719 stabilizes the structure of PI3Kα, but three regions of low-resolution extra density remain and are provisionally assigned to the cSH2, BH, and SH3 domains of p85. One of the extra density regions is in contact with the kinase domain blocking access to the catalytic site. This conformational change indicates that the effects of BYL-719 on PI3Kα activity extend beyond competition with adenosine triphosphate (ATP). In unliganded PI3Kα, the DFG motif occurs in the “in” and “out” positions. In BYL-719–bound PI3Kα, only the DFG-in position, corresponding to the active conformation of the kinase, was observed. The phosphopeptide-bound structure of PI3Kα is composed of a stable core resolved at 3.8 Å. It contains all p110α domains except the adaptor-binding domain (ABD). The p85α domains, linked to the core through the ABD, are no longer resolved, implying that the phosphopeptide activates PI3Kα by fully releasing the niSH2 domain from binding to p110α. The structures presented here show the basal form of the full-length PI3Kα dimer and document conformational changes related to the activated and inhibited states.
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277
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Radamaker L, Karimi-Farsijani S, Andreotti G, Baur J, Neumann M, Schreiner S, Berghaus N, Motika R, Haupt C, Walther P, Schmidt V, Huhn S, Hegenbart U, Schönland SO, Wiese S, Read C, Schmidt M, Fändrich M. Role of mutations and post-translational modifications in systemic AL amyloidosis studied by cryo-EM. Nat Commun 2021; 12:6434. [PMID: 34741031 PMCID: PMC8571268 DOI: 10.1038/s41467-021-26553-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 10/01/2021] [Indexed: 12/29/2022] Open
Abstract
Systemic AL amyloidosis is a rare disease that is caused by the misfolding of immunoglobulin light chains (LCs). Potential drivers of amyloid formation in this disease are post-translational modifications (PTMs) and the mutational changes that are inserted into the LCs by somatic hypermutation. Here we present the cryo electron microscopy (cryo-EM) structure of an ex vivo λ1-AL amyloid fibril whose deposits disrupt the ordered cardiomyocyte structure in the heart. The fibril protein contains six mutational changes compared to the germ line and three PTMs (disulfide bond, N-glycosylation and pyroglutamylation). Our data imply that the disulfide bond, glycosylation and mutational changes contribute to determining the fibril protein fold and help to generate a fibril morphology that is able to withstand proteolytic degradation inside the body.
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Affiliation(s)
- Lynn Radamaker
- Institute of Protein Biochemistry, Ulm University, 89081, Ulm, Germany
| | | | - Giada Andreotti
- Institute of Protein Biochemistry, Ulm University, 89081, Ulm, Germany
| | - Julian Baur
- Institute of Protein Biochemistry, Ulm University, 89081, Ulm, Germany
| | | | - Sarah Schreiner
- Medical Department V, Section of Multiple Myeloma, Heidelberg University Hospital, 69120, Heidelberg, Germany
| | - Natalie Berghaus
- Medical Department V, Section of Multiple Myeloma, Heidelberg University Hospital, 69120, Heidelberg, Germany
| | - Raoul Motika
- Department of Asia-Africa-Studies, Middle Eastern History and Culture, University of Hamburg, 20148, Hamburg, Germany
| | - Christian Haupt
- Institute of Protein Biochemistry, Ulm University, 89081, Ulm, Germany
| | - Paul Walther
- Central Facility for Electron Microscopy, Ulm University, 89081, Ulm, Germany
| | - Volker Schmidt
- Institute of Stochastics, Ulm University, 89081, Ulm, Germany
| | - Stefanie Huhn
- Medical Department V, Section of Multiple Myeloma, Heidelberg University Hospital, 69120, Heidelberg, Germany
| | - Ute Hegenbart
- Medical Department V, Amyloidosis Center, Heidelberg University Hospital, 69120, Heidelberg, Germany
| | - Stefan O Schönland
- Medical Department V, Amyloidosis Center, Heidelberg University Hospital, 69120, Heidelberg, Germany
| | - Sebastian Wiese
- Core Unit Mass Spectrometry and Proteomics, Medical Faculty, Ulm University, 89081, Ulm, Germany
| | - Clarissa Read
- Central Facility for Electron Microscopy, Ulm University, 89081, Ulm, Germany
- Institute of Virology, Ulm University Medical Center, 89081, Ulm, Germany
| | - Matthias Schmidt
- Institute of Protein Biochemistry, Ulm University, 89081, Ulm, Germany
| | - Marcus Fändrich
- Institute of Protein Biochemistry, Ulm University, 89081, Ulm, Germany.
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278
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Francis MLR, Webby MN, Housden NG, Kaminska R, Elliston E, Chinthammit B, Lukoyanova N, Kleanthous C. Porin threading drives receptor disengagement and establishes active colicin transport through Escherichia coli OmpF. EMBO J 2021; 40:e108610. [PMID: 34515361 PMCID: PMC8561637 DOI: 10.15252/embj.2021108610] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 08/09/2021] [Accepted: 08/17/2021] [Indexed: 11/24/2022] Open
Abstract
Bacteria deploy weapons to kill their neighbours during competition for resources and to aid survival within microbiomes. Colicins were the first such antibacterial system identified, yet how these bacteriocins cross the outer membrane (OM) of Escherichia coli is unknown. Here, by solving the structures of translocation intermediates via cryo‐EM and by imaging toxin import, we uncover the mechanism by which the Tol‐dependent nuclease colicin E9 (ColE9) crosses the bacterial OM. We show that threading of ColE9’s disordered N‐terminal domain through two pores of the trimeric porin OmpF causes the colicin to disengage from its primary receptor, BtuB, and reorganises the translocon either side of the membrane. Subsequent import of ColE9 through the lumen of a single OmpF subunit is driven by the proton‐motive force, which is delivered by the TolQ‐TolR‐TolA‐TolB assembly. Our study answers longstanding questions, such as why OmpF is a better translocator than OmpC, and reconciles the mechanisms by which both Tol‐ and Ton‐dependent bacteriocins cross the bacterial outer membrane.
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Affiliation(s)
| | - Melissa N Webby
- Department of Biochemistry, University of Oxford, Oxford, UK
| | | | - Renata Kaminska
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Emma Elliston
- Department of Biochemistry, University of Oxford, Oxford, UK
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279
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Simpkin AJ, Winn MD, Rigden DJ, Keegan RM. Redeployment of automated MrBUMP search-model identification for map fitting in cryo-EM. Acta Crystallogr D Struct Biol 2021; 77:1378-1385. [PMID: 34726166 PMCID: PMC8561737 DOI: 10.1107/s2059798321009165] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 09/03/2021] [Indexed: 11/22/2022] Open
Abstract
In crystallography, the phase problem can often be addressed by the careful preparation of molecular-replacement search models. This has led to the development of pipelines such as MrBUMP that can automatically identify homologous proteins from an input sequence and edit them to focus on the areas that are most conserved. Many of these approaches can be applied directly to cryo-EM to help discover, prepare and correctly place models (here called cryo-EM search models) into electrostatic potential maps. This can significantly reduce the amount of manual model building that is required for structure determination. Here, MrBUMP is repurposed to fit automatically obtained PDB-derived chains and domains into cryo-EM maps. MrBUMP was successfully able to identify and place cryo-EM search models across a range of resolutions. Methods such as map segmentation are also explored as potential routes to improved performance. Map segmentation was also found to improve the effectiveness of the pipeline for higher resolution (<8 Å) data sets.
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Affiliation(s)
- Adam J. Simpkin
- Institute of Structural, Molecular and Integrative Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom
| | - Martyn D. Winn
- UKRI–STFC, Rutherford Appleton Laboratory, Research Complex at Harwell, Didcot OX11 0FA, United Kingdom
| | - Daniel J. Rigden
- Institute of Structural, Molecular and Integrative Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom
| | - Ronan M. Keegan
- UKRI–STFC, Rutherford Appleton Laboratory, Research Complex at Harwell, Didcot OX11 0FA, United Kingdom
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280
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Structural basis of soluble membrane attack complex packaging for clearance. Nat Commun 2021; 12:6086. [PMID: 34667172 PMCID: PMC8526713 DOI: 10.1038/s41467-021-26366-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 10/01/2021] [Indexed: 12/15/2022] Open
Abstract
Unregulated complement activation causes inflammatory and immunological pathologies with consequences for human disease. To prevent bystander damage during an immune response, extracellular chaperones (clusterin and vitronectin) capture and clear soluble precursors to the membrane attack complex (sMAC). However, how these chaperones block further polymerization of MAC and prevent the complex from binding target membranes remains unclear. Here, we address that question by combining cryo electron microscopy (cryoEM) and cross-linking mass spectrometry (XL-MS) to solve the structure of sMAC. Together our data reveal how clusterin recognizes and inhibits polymerizing complement proteins by binding a negatively charged surface of sMAC. Furthermore, we show that the pore-forming C9 protein is trapped in an intermediate conformation whereby only one of its two transmembrane β-hairpins has unfurled. This structure provides molecular details for immune pore formation and helps explain a complement control mechanism that has potential implications for how cell clearance pathways mediate immune homeostasis. To prevent unregulated complement activation, extracellular chaperones capture soluble precursors to the membrane attack complex (sMAC). Here, structural analysis of sMAC reveals how clusterin recognizes heterogeneous sMAC complexes and inhibits polymerization of complement protein C9.
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281
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Scortecci JF, Molday LL, Curtis SB, Garces FA, Panwar P, Van Petegem F, Molday RS. Cryo-EM structures of the ABCA4 importer reveal mechanisms underlying substrate binding and Stargardt disease. Nat Commun 2021; 12:5902. [PMID: 34625547 PMCID: PMC8501128 DOI: 10.1038/s41467-021-26161-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 09/20/2021] [Indexed: 12/04/2022] Open
Abstract
ABCA4 is an ATP-binding cassette (ABC) transporter that flips N-retinylidene-phosphatidylethanolamine (N-Ret-PE) from the lumen to the cytoplasmic leaflet of photoreceptor membranes. Loss-of-function mutations cause Stargardt disease (STGD1), a macular dystrophy associated with severe vision loss. To define the mechanisms underlying substrate binding and STGD1, we determine the cryo-EM structure of ABCA4 in its substrate-free and bound states. The two structures are similar and delineate an elongated protein with the two transmembrane domains (TMD) forming an outward facing conformation, extended and twisted exocytoplasmic domains (ECD), and closely opposed nucleotide binding domains. N-Ret-PE is wedged between the two TMDs and a loop from ECD1 within the lumen leaflet consistent with a lateral access mechanism and is stabilized through hydrophobic and ionic interactions with residues from the TMDs and ECDs. Our studies provide a framework for further elucidating the molecular mechanism associated with lipid transport and disease and developing promising disease interventions.
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Affiliation(s)
| | - Laurie L Molday
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
| | - Susan B Curtis
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
| | - Fabian A Garces
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
| | - Pankaj Panwar
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
| | - Robert S Molday
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada.
- Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, BC, Canada.
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282
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Olia AS, Tsybovsky Y, Chen SJ, Liu C, Nazzari AF, Ou L, Wang L, Kong WP, Leung K, Liu T, Stephens T, Teng IT, Wang S, Yang ES, Zhang B, Zhang Y, Zhou T, Mascola JR, Kwong PD. SARS-CoV-2 S2P spike ages through distinct states with altered immunogenicity. J Biol Chem 2021; 297:101127. [PMID: 34461095 PMCID: PMC8393506 DOI: 10.1016/j.jbc.2021.101127] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 08/17/2021] [Accepted: 08/26/2021] [Indexed: 12/14/2022] Open
Abstract
The SARS-CoV-2 spike is the primary target of virus-neutralizing antibodies and critical to the development of effective vaccines against COVID-19. Here, we demonstrate that the prefusion-stabilized two-proline "S2P" spike-widely employed for laboratory work and clinical studies-unfolds when stored at 4 °C, physiological pH, as observed by electron microscopy (EM) and differential scanning calorimetry, but that its trimeric, native-like conformation can be reacquired by low pH treatment. When stored for approximately 1 week, this unfolding does not significantly alter antigenic characteristics; however, longer storage diminishes antibody binding, and month-old spike elicits virtually no neutralization in mice despite inducing high ELISA-binding titers. Cryo-EM structures reveal the folded fraction of spike to decrease with aging; however, its structure remains largely similar, although with varying mobility of the receptor-binding domain. Thus, the SARS-CoV-2 spike is susceptible to unfolding, which affects immunogenicity, highlighting the need to monitor its integrity.
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Affiliation(s)
- Adam S Olia
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Yaroslav Tsybovsky
- Vaccine Research Center Electron Microscopy Unit, Cancer Research Technology Program, Leidos Biomedical Research Inc, Frederick National Laboratory for Cancer Research, Frederick, Maryland, USA
| | - Steven J Chen
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Cuiping Liu
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Alexandra F Nazzari
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Li Ou
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Lingshu Wang
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Wing-Pui Kong
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Kwan Leung
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Tracy Liu
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Tyler Stephens
- Vaccine Research Center Electron Microscopy Unit, Cancer Research Technology Program, Leidos Biomedical Research Inc, Frederick National Laboratory for Cancer Research, Frederick, Maryland, USA
| | - I-Ting Teng
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Shuishu Wang
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Eun Sung Yang
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Baoshan Zhang
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Yi Zhang
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Tongqing Zhou
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - John R Mascola
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Peter D Kwong
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA.
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283
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Huo J, Mikolajek H, Le Bas A, Clark JJ, Sharma P, Kipar A, Dormon J, Norman C, Weckener M, Clare DK, Harrison PJ, Tree JA, Buttigieg KR, Salguero FJ, Watson R, Knott D, Carnell O, Ngabo D, Elmore MJ, Fotheringham S, Harding A, Moynié L, Ward PN, Dumoux M, Prince T, Hall Y, Hiscox JA, Owen A, James W, Carroll MW, Stewart JP, Naismith JH, Owens RJ. A potent SARS-CoV-2 neutralising nanobody shows therapeutic efficacy in the Syrian golden hamster model of COVID-19. Nat Commun 2021; 12:5469. [PMID: 34552091 PMCID: PMC8458290 DOI: 10.1038/s41467-021-25480-z] [Citation(s) in RCA: 87] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 08/12/2021] [Indexed: 12/18/2022] Open
Abstract
SARS-CoV-2 remains a global threat to human health particularly as escape mutants emerge. There is an unmet need for effective treatments against COVID-19 for which neutralizing single domain antibodies (nanobodies) have significant potential. Their small size and stability mean that nanobodies are compatible with respiratory administration. We report four nanobodies (C5, H3, C1, F2) engineered as homotrimers with pmolar affinity for the receptor binding domain (RBD) of the SARS-CoV-2 spike protein. Crystal structures show C5 and H3 overlap the ACE2 epitope, whilst C1 and F2 bind to a different epitope. Cryo Electron Microscopy shows C5 binding results in an all down arrangement of the Spike protein. C1, H3 and C5 all neutralize the Victoria strain, and the highly transmissible Alpha (B.1.1.7 first identified in Kent, UK) strain and C1 also neutralizes the Beta (B.1.35, first identified in South Africa). Administration of C5-trimer via the respiratory route showed potent therapeutic efficacy in the Syrian hamster model of COVID-19 and separately, effective prophylaxis. The molecule was similarly potent by intraperitoneal injection.
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MESH Headings
- Administration, Intranasal
- Animals
- Antibodies, Neutralizing/administration & dosage
- Antibodies, Neutralizing/genetics
- Antibodies, Neutralizing/immunology
- Antibodies, Neutralizing/pharmacology
- Cryoelectron Microscopy
- Crystallography, X-Ray
- Disease Models, Animal
- Dose-Response Relationship, Immunologic
- Epitopes/chemistry
- Epitopes/metabolism
- Female
- Male
- Mesocricetus
- Neutralization Tests
- SARS-CoV-2/drug effects
- Single-Domain Antibodies/administration & dosage
- Single-Domain Antibodies/immunology
- Single-Domain Antibodies/metabolism
- Single-Domain Antibodies/pharmacology
- Spike Glycoprotein, Coronavirus/chemistry
- Spike Glycoprotein, Coronavirus/metabolism
- COVID-19 Drug Treatment
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Affiliation(s)
- Jiandong Huo
- Structural Biology, The Rosalind Franklin Institute, Harwell Science Campus, Didcot, UK
- Division of Structural Biology, The Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
- Protein Production UK, The Rosalind Franklin Institute - Diamond Light Source, The Research Complex at Harwell, Science Campus, Didcot, UK
| | | | - Audrey Le Bas
- Structural Biology, The Rosalind Franklin Institute, Harwell Science Campus, Didcot, UK
- Division of Structural Biology, The Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
- Protein Production UK, The Rosalind Franklin Institute - Diamond Light Source, The Research Complex at Harwell, Science Campus, Didcot, UK
| | - Jordan J Clark
- Department of Infection Biology & Microbiomes, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - Parul Sharma
- Department of Infection Biology & Microbiomes, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - Anja Kipar
- Department of Infection Biology & Microbiomes, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
- Laboratory for Animal Model Pathology, Institute of Veterinary Pathology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Joshua Dormon
- Structural Biology, The Rosalind Franklin Institute, Harwell Science Campus, Didcot, UK
- Protein Production UK, The Rosalind Franklin Institute - Diamond Light Source, The Research Complex at Harwell, Science Campus, Didcot, UK
| | - Chelsea Norman
- Structural Biology, The Rosalind Franklin Institute, Harwell Science Campus, Didcot, UK
- Protein Production UK, The Rosalind Franklin Institute - Diamond Light Source, The Research Complex at Harwell, Science Campus, Didcot, UK
| | - Miriam Weckener
- Structural Biology, The Rosalind Franklin Institute, Harwell Science Campus, Didcot, UK
| | - Daniel K Clare
- Diamond Light Source Ltd, Harwell Science Campus, Didcot, UK
| | - Peter J Harrison
- Protein Production UK, The Rosalind Franklin Institute - Diamond Light Source, The Research Complex at Harwell, Science Campus, Didcot, UK
- Diamond Light Source Ltd, Harwell Science Campus, Didcot, UK
| | - Julia A Tree
- National Infection Service, Public Health England, Porton Down, Salisbury, UK
| | - Karen R Buttigieg
- National Infection Service, Public Health England, Porton Down, Salisbury, UK
| | | | - Robert Watson
- National Infection Service, Public Health England, Porton Down, Salisbury, UK
| | - Daniel Knott
- National Infection Service, Public Health England, Porton Down, Salisbury, UK
| | - Oliver Carnell
- National Infection Service, Public Health England, Porton Down, Salisbury, UK
| | - Didier Ngabo
- National Infection Service, Public Health England, Porton Down, Salisbury, UK
| | - Michael J Elmore
- National Infection Service, Public Health England, Porton Down, Salisbury, UK
| | - Susan Fotheringham
- National Infection Service, Public Health England, Porton Down, Salisbury, UK
| | - Adam Harding
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Lucile Moynié
- Structural Biology, The Rosalind Franklin Institute, Harwell Science Campus, Didcot, UK
| | - Philip N Ward
- Division of Structural Biology, The Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
- Protein Production UK, The Rosalind Franklin Institute - Diamond Light Source, The Research Complex at Harwell, Science Campus, Didcot, UK
| | - Maud Dumoux
- Structural Biology, The Rosalind Franklin Institute, Harwell Science Campus, Didcot, UK
| | - Tessa Prince
- Diamond Light Source Ltd, Harwell Science Campus, Didcot, UK
| | - Yper Hall
- National Infection Service, Public Health England, Porton Down, Salisbury, UK
| | - Julian A Hiscox
- Diamond Light Source Ltd, Harwell Science Campus, Didcot, UK
- Department of Preventive Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, China
- Infectious Diseases Horizontal Technology Centre (ID HTC), A*STAR, Singapore, Singapore
| | - Andrew Owen
- Department of Pharmacology and Therapeutics, Centre of Excellence in Long-acting Therapeutics (CELT), University of Liverpool, Liverpool, UK
| | - William James
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Miles W Carroll
- National Infection Service, Public Health England, Porton Down, Salisbury, UK
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - James P Stewart
- Diamond Light Source Ltd, Harwell Science Campus, Didcot, UK
- Department of Preventive Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, China
- Department of Infectious Disease, University of Georgia, Georgia, USA
| | - James H Naismith
- Structural Biology, The Rosalind Franklin Institute, Harwell Science Campus, Didcot, UK.
- Division of Structural Biology, The Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK.
- Protein Production UK, The Rosalind Franklin Institute - Diamond Light Source, The Research Complex at Harwell, Science Campus, Didcot, UK.
| | - Raymond J Owens
- Structural Biology, The Rosalind Franklin Institute, Harwell Science Campus, Didcot, UK.
- Division of Structural Biology, The Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK.
- Protein Production UK, The Rosalind Franklin Institute - Diamond Light Source, The Research Complex at Harwell, Science Campus, Didcot, UK.
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284
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Unwinding of a DNA replication fork by a hexameric viral helicase. Nat Commun 2021; 12:5535. [PMID: 34545080 PMCID: PMC8452682 DOI: 10.1038/s41467-021-25843-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 08/31/2021] [Indexed: 11/16/2022] Open
Abstract
Hexameric helicases are motor proteins that unwind double-stranded DNA (dsDNA) during DNA replication but how they are optimised for strand separation is unclear. Here we present the cryo-EM structure of the full-length E1 helicase from papillomavirus, revealing all arms of a bound DNA replication fork and their interactions with the helicase. The replication fork junction is located at the entrance to the helicase collar ring, that sits above the AAA + motor assembly. dsDNA is escorted to and the 5´ single-stranded DNA (ssDNA) away from the unwinding point by the E1 dsDNA origin binding domains. The 3´ ssDNA interacts with six spirally-arranged β-hairpins and their cyclical top-to-bottom movement pulls the ssDNA through the helicase. Pulling of the RF against the collar ring separates the base-pairs, while modelling of the conformational cycle suggest an accompanying movement of the collar ring has an auxiliary role, helping to make efficient use of ATP in duplex unwinding. Replicative hexameric helicases are fundamental components of replisomes. Here the authors resolve a cryo-EM structure of the E1 helicase from papillomavirus bound to a DNA replication fork, providing insights into the mechanism of DNA unwinding by these hexameric enzymes.
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285
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Pintilie G, Chiu W. Validation, analysis and annotation of cryo-EM structures. Acta Crystallogr D Struct Biol 2021; 77:1142-1152. [PMID: 34473085 PMCID: PMC8411978 DOI: 10.1107/s2059798321006069] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 06/09/2021] [Indexed: 11/08/2023] Open
Abstract
The process of turning 2D micrographs into 3D atomic models of the imaged macromolecules has been under rapid development and scrutiny in the field of cryo-EM. Here, some important methods for validation at several stages in this process are described. Firstly, how Fourier shell correlation of two independent maps and phase randomization beyond a certain frequency address the assessment of map resolution is reviewed. Techniques for local resolution estimation and map sharpening are also touched upon. The topic of validating models which are either built de novo or based on a known atomic structure fitted into a cryo-EM map is then approached. Map-model comparison using Q-scores and Fourier shell correlation plots is used to assure the agreement of the model with the observed map density. The importance of annotating the model with B factors to account for the resolvability of individual atoms in the map is illustrated. Finally, the timely topic of detecting and validating water molecules and metal ions in maps that have surpassed ∼2 Å resolution is described.
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Affiliation(s)
- Grigore Pintilie
- Department of Bioengineering, James H. Clark Center, Stanford University, Stanford, CA 94305, USA
| | - Wah Chiu
- Department of Bioengineering, James H. Clark Center, Stanford University, Stanford, CA 94305, USA
- Division of Cryo-EM and Bioimaging, SSRL, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, CA 94025, USA
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286
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The structure of the bacterial DNA segregation ATPase filament reveals the conformational plasticity of ParA upon DNA binding. Nat Commun 2021; 12:5166. [PMID: 34453062 PMCID: PMC8397727 DOI: 10.1038/s41467-021-25429-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 08/11/2021] [Indexed: 02/02/2023] Open
Abstract
The efficient segregation of replicated genetic material is an essential step for cell division. Bacterial cells use several evolutionarily-distinct genome segregation systems, the most common of which is the type I Par system. It consists of an adapter protein, ParB, that binds to the DNA cargo via interaction with the parS DNA sequence; and an ATPase, ParA, that binds nonspecific DNA and mediates cargo transport. However, the molecular details of how this system functions are not well understood. Here, we report the cryo-EM structure of the Vibrio cholerae ParA2 filament bound to DNA, as well as the crystal structures of this protein in various nucleotide states. These structures show that ParA forms a left-handed filament on DNA, stabilized by nucleotide binding, and that ParA undergoes profound structural rearrangements upon DNA binding and filament assembly. Collectively, our data suggest the structural basis for ParA’s cooperative binding to DNA and the formation of high ParA density regions on the nucleoid. ParA is an ATPase involved in the segregation of newly replicated DNA in bacteria. Here, structures of a ParA filament bound to DNA and of ParA in various nucleotide states offer insight into its conformational changes upon DNA binding and filament assembly, including the basis for ParA’s cooperative binding to DNA.
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287
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Harshbarger W, Abeyrathne PD, Tian S, Huang Y, Chandramouli S, Bottomley MJ, Malito E. Improved epitope resolution of the prefusion trimer-specific antibody AM14 bound to the RSV F glycoprotein. MAbs 2021; 13:1955812. [PMID: 34420474 PMCID: PMC8386734 DOI: 10.1080/19420862.2021.1955812] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
Respiratory syncytial virus (RSV) is the most common cause of acute lower respiratory tract infections resulting in medical intervention and hospitalizations during infancy and early childhood, and vaccination against RSV remains a public health priority. The RSV F glycoprotein is a major target of neutralizing antibodies, and the prefusion stabilized form of F (DS-Cav1) is under investigation as a vaccine antigen. AM14 is a human monoclonal antibody with the exclusive capacity of binding an epitope on prefusion F (PreF), which spans two F protomers. The quality of recognizing a trimer-specific epitope makes AM14 valuable for probing PreF-based immunogen conformation and functionality during vaccine production. Currently, only a low-resolution (5.5 Å) X-ray structure is available of the PreF-AM14 complex, revealing few reliable details of the interface. Here, we perform complementary structural studies using X-ray crystallography and cryo-electron microscopy (cryo-EM) to provide improved resolution structures at 3.6 Å and 3.4 Å resolutions, respectively. Both X-ray and cryo-EM structures provide clear side-chain densities, which allow for accurate mapping of the AM14 epitope on DS-Cav1. The structures help rationalize the molecular basis for AM14 loss of binding to RSV F monoclonal antibody-resistant mutants and reveal flexibility for the side chain of a key antigenic residue on PreF. This work provides the basis for a comprehensive understanding of RSV F trimer specificity with implications in vaccine design and quality assessment of PreF-based immunogens.
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Affiliation(s)
| | | | - Sai Tian
- GSK, Vaccine Design and Cellular Immunology, Rockville, MD, USA
| | - Ying Huang
- GSK, Vaccine Design and Cellular Immunology, Rockville, MD, USA
| | | | | | - Enrico Malito
- GSK, Vaccine Design and Cellular Immunology, Rockville, MD, USA
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288
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Structures of tmRNA and SmpB as they transit through the ribosome. Nat Commun 2021; 12:4909. [PMID: 34389707 PMCID: PMC8363625 DOI: 10.1038/s41467-021-24881-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 07/13/2021] [Indexed: 01/01/2023] Open
Abstract
In bacteria, trans-translation is the main rescue system, freeing ribosomes stalled on defective messenger RNAs. This mechanism is driven by small protein B (SmpB) and transfer-messenger RNA (tmRNA), a hybrid RNA known to have both a tRNA-like and an mRNA-like domain. Here we present four cryo-EM structures of the ribosome during trans-translation at resolutions from 3.0 to 3.4 Å. These include the high-resolution structure of the whole pre-accommodated state, as well as structures of the accommodated state, the translocated state, and a translocation intermediate. Together, they shed light on the movements of the tmRNA-SmpB complex in the ribosome, from its delivery by the elongation factor EF-Tu to its passage through the ribosomal A and P sites after the opening of the B1 bridges. Additionally, we describe the interactions between the tmRNA-SmpB complex and the ribosome. These explain why the process does not interfere with canonical translation.
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289
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Sorzano COS, Jiménez-Moreno A, Maluenda D, Ramírez-Aportela E, Martínez M, Cuervo A, Melero R, Conesa JJ, Sánchez-García R, Strelak D, Filipovic J, Fernández-Giménez E, de Isidro-Gómez F, Herreros D, Conesa P, Del Caño L, Fonseca Y, de la Morena JJ, Macías JR, Losana P, Marabini R, Carazo JM. Image Processing in Cryo-Electron Microscopy of Single Particles: The Power of Combining Methods. Methods Mol Biol 2021; 2305:257-289. [PMID: 33950394 DOI: 10.1007/978-1-0716-1406-8_13] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Cryo-electron microscopy has established as a mature structural biology technique to elucidate the three-dimensional structure of biological macromolecules. The Coulomb potential of the sample is imaged by an electron beam, and fast semi-conductor detectors produce movies of the sample under study. These movies have to be further processed by a whole pipeline of image-processing algorithms that produce the final structure of the macromolecule. In this chapter, we illustrate this whole processing pipeline putting in value the strength of "meta algorithms," which are the combination of several algorithms, each one with different mathematical rationale, in order to distinguish correctly from incorrectly estimated parameters. We show how this strategy leads to superior performance of the whole pipeline as well as more confident assessments about the reconstructed structures. The "meta algorithms" strategy is common to many fields and, in particular, it has provided excellent results in bioinformatics. We illustrate this combination using the workflow engine, Scipion.
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Affiliation(s)
| | | | | | | | | | - Ana Cuervo
- National Centre for Biotechnology (CSIC), Madrid, Spain
| | - Robert Melero
- National Centre for Biotechnology (CSIC), Madrid, Spain
| | | | | | - David Strelak
- National Centre for Biotechnology (CSIC), Madrid, Spain
| | | | | | | | | | - Pablo Conesa
- National Centre for Biotechnology (CSIC), Madrid, Spain
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290
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Yu J, Raia P, Ghent CM, Raisch T, Sadian Y, Cavadini S, Sabale PM, Barford D, Raunser S, Morgan DO, Boland A. Structural basis of human separase regulation by securin and CDK1-cyclin B1. Nature 2021; 596:138-142. [PMID: 34290405 PMCID: PMC8482764 DOI: 10.1038/s41586-021-03764-0] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Accepted: 06/23/2021] [Indexed: 02/06/2023]
Abstract
In early mitosis, the duplicated chromosomes are held together by the ring-shaped cohesin complex1. Separation of chromosomes during anaphase is triggered by separase-a large cysteine endopeptidase that cleaves the cohesin subunit SCC1 (also known as RAD212-4). Separase is activated by degradation of its inhibitors, securin5 and cyclin B6, but the molecular mechanisms of separase regulation are not clear. Here we used cryogenic electron microscopy to determine the structures of human separase in complex with either securin or CDK1-cyclin B1-CKS1. In both complexes, separase is inhibited by pseudosubstrate motifs that block substrate binding at the catalytic site and at nearby docking sites. As in Caenorhabditis elegans7 and yeast8, human securin contains its own pseudosubstrate motifs. By contrast, CDK1-cyclin B1 inhibits separase by deploying pseudosubstrate motifs from intrinsically disordered loops in separase itself. One autoinhibitory loop is oriented by CDK1-cyclin B1 to block the catalytic sites of both separase and CDK19,10. Another autoinhibitory loop blocks substrate docking in a cleft adjacent to the separase catalytic site. A third separase loop contains a phosphoserine6 that promotes complex assembly by binding to a conserved phosphate-binding pocket in cyclin B1. Our study reveals the diverse array of mechanisms by which securin and CDK1-cyclin B1 bind and inhibit separase, providing the molecular basis for the robust control of chromosome segregation.
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Affiliation(s)
- Jun Yu
- Department of Molecular Biology, University of Geneva, Geneva, Switzerland
| | - Pierre Raia
- Department of Molecular Biology, University of Geneva, Geneva, Switzerland
| | - Chloe M Ghent
- Department of Physiology, University of California, San Francisco, San Francisco, CA, USA
| | - Tobias Raisch
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Yashar Sadian
- Bioimaging Center, University of Geneva, Geneva, Switzerland
| | - Simone Cavadini
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Pramod M Sabale
- Department of Organic Chemistry, NCCR Chemical Biology, University of Geneva, Geneva, Switzerland
| | | | - Stefan Raunser
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - David O Morgan
- Department of Physiology, University of California, San Francisco, San Francisco, CA, USA
| | - Andreas Boland
- Department of Molecular Biology, University of Geneva, Geneva, Switzerland.
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291
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Pausch P, Soczek KM, Herbst DA, Tsuchida CA, Al-Shayeb B, Banfield JF, Nogales E, Doudna JA. DNA interference states of the hypercompact CRISPR-CasΦ effector. Nat Struct Mol Biol 2021; 28:652-661. [PMID: 34381246 PMCID: PMC8496406 DOI: 10.1038/s41594-021-00632-3] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 06/24/2021] [Indexed: 12/26/2022]
Abstract
CRISPR-CasΦ, a small RNA-guided enzyme found uniquely in bacteriophages, achieves programmable DNA cutting as well as genome editing. To investigate how the hypercompact enzyme recognizes and cleaves double-stranded DNA, we determined cryo-EM structures of CasΦ (Cas12j) in pre- and post-DNA-binding states. The structures reveal a streamlined protein architecture that tightly encircles the CRISPR RNA and DNA target to capture, unwind and cleave DNA. Comparison of the pre- and post-DNA-binding states reveals how the protein rearranges for DNA cleavage upon target recognition. On the basis of these structures, we created and tested mutant forms of CasΦ that cut DNA up to 20-fold faster relative to wild type, showing how this system may be naturally attenuated to improve the fidelity of DNA interference. The structural and mechanistic insights into how CasΦ binds and cleaves DNA should allow for protein engineering for both in vitro diagnostics and genome editing.
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Affiliation(s)
- Patrick Pausch
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA, USA
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, Berkeley, CA, USA
- VU LSC-EMBL Partnership for Genome Editing Technologies, Life Sciences Center, Vilnius University, Vilnius, Lithuania
| | - Katarzyna M Soczek
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA, USA
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, Berkeley, CA, USA
| | - Dominik A Herbst
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, Berkeley, CA, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Connor A Tsuchida
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA, USA
- University of California, Berkeley-University of California, San Francisco Graduate Program in Bioengineering, Berkeley, CA, USA
| | - Basem Al-Shayeb
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA, USA
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Jillian F Banfield
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA, USA
- Department of Earth and Planetary Sciences, University of California, Berkeley, Berkeley, CA, USA
| | - Eva Nogales
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, Berkeley, CA, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Howard Hughes Medical Institute, Baltimore, MD, USA
| | - Jennifer A Doudna
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA, USA.
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA.
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, Berkeley, CA, USA.
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
- Howard Hughes Medical Institute, Baltimore, MD, USA.
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, USA.
- Gladstone Institute of Data Science and Biotechnology, Gladstone Institutes, San Francisco, CA, USA.
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292
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Gijsbers A, Zhang Y, Gao Y, Peters PJ, Ravelli RBG. Mycobacterium tuberculosis ferritin: a suitable workhorse protein for cryo-EM development. Acta Crystallogr D Struct Biol 2021; 77:1077-1083. [PMID: 34342280 PMCID: PMC8329864 DOI: 10.1107/s2059798321007233] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Accepted: 07/13/2021] [Indexed: 11/10/2022] Open
Abstract
The use of cryo-EM continues to expand worldwide and calls for good-quality standard proteins with simple protocols for their production. Here, a straightforward expression and purification protocol is presented that provides an apoferritin, bacterioferritin B (BfrB), from Mycobacterium tuberculosis with high yield and purity. A 2.12 Å resolution cryo-EM structure of BfrB is reported, showing the typical cage-like oligomer constituting of 24 monomers related by 432 symmetry. However, it also contains a unique C-terminal extension (164-181), which loops into the cage region of the shell and provides extra stability to the protein. Part of this region was ambiguous in previous crystal structures but could be built within the cryo-EM map. These findings and this protocol could serve the growing cryo-EM community in characterizing and pushing the limits of their electron microscopes and workflows.
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Affiliation(s)
- Abril Gijsbers
- Maastricht Multimodal Molecular Imaging Institute, Division of Nanoscopy, Maastricht University, Universiteitssingel 50, 6229 ER Maastricht, The Netherlands
| | - Yue Zhang
- Maastricht Multimodal Molecular Imaging Institute, Division of Nanoscopy, Maastricht University, Universiteitssingel 50, 6229 ER Maastricht, The Netherlands
| | - Ye Gao
- Maastricht Multimodal Molecular Imaging Institute, Division of Nanoscopy, Maastricht University, Universiteitssingel 50, 6229 ER Maastricht, The Netherlands
| | - Peter J. Peters
- Maastricht Multimodal Molecular Imaging Institute, Division of Nanoscopy, Maastricht University, Universiteitssingel 50, 6229 ER Maastricht, The Netherlands
| | - Raimond B. G. Ravelli
- Maastricht Multimodal Molecular Imaging Institute, Division of Nanoscopy, Maastricht University, Universiteitssingel 50, 6229 ER Maastricht, The Netherlands
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293
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Minimal protein-only RNase P structure reveals insights into tRNA precursor recognition and catalysis. J Biol Chem 2021; 297:101028. [PMID: 34339732 PMCID: PMC8405995 DOI: 10.1016/j.jbc.2021.101028] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 07/20/2021] [Accepted: 07/29/2021] [Indexed: 11/22/2022] Open
Abstract
Ribonuclease P (RNase P) is an endoribonuclease that catalyzes the processing of the 5' leader sequence of precursor tRNA (pre-tRNA). Ribonucleoprotein RNase P and protein-only RNase P (PRORP) in eukaryotes have been extensively studied, but the mechanism by which a prokaryotic nuclease recognizes and cleaves pre-tRNA is unclear. To gain insights into this mechanism, we studied homologs of Aquifex RNase P (HARPs), thought to be enzymes of approximately 23 kDa comprising only this nuclease domain. We determined the cryo-EM structure of Aq880, the first identified HARP enzyme. The structure unexpectedly revealed that Aq880 consists of both the nuclease and protruding helical (PrH) domains. Aq880 monomers assemble into a dimer via the PrH domain. Six dimers form a dodecamer with a left-handed one-turn superhelical structure. The structure also revealed that the active site of Aq880 is analogous to that of eukaryotic PRORPs. The pre-tRNA docking model demonstrated that 5' processing of pre-tRNAs is achieved by two adjacent dimers within the dodecamer. One dimer is responsible for catalysis, and the PrH domains of the other dimer are responsible for pre-tRNA elbow recognition. Our study suggests that HARPs measure an invariant distance from the pre-tRNA elbow to cleave the 5' leader sequence, which is analogous to the mechanism of eukaryotic PRORPs and the ribonucleoprotein RNase P. Collectively, these findings shed light on how different types of RNase P enzymes utilize the same pre-tRNA processing.
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294
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Abstract
Bacteria often secrete diffusible protein toxins (bacteriocins) to kill bystander cells during interbacterial competition. Here, we use biochemical, biophysical and structural analyses to show how a bacteriocin exploits TolC, a major outer-membrane antibiotic efflux channel in Gram-negative bacteria, to transport itself across the outer membrane of target cells. Klebicin C (KlebC), a rRNase toxin produced by Klebsiella pneumoniae, binds TolC of a related species (K. quasipneumoniae) with high affinity through an N-terminal, elongated helical hairpin domain common amongst bacteriocins. The KlebC helical hairpin opens like a switchblade to bind TolC. A cryo-EM structure of this partially translocated state, at 3.1 Å resolution, reveals that KlebC associates along the length of the TolC channel. Thereafter, the unstructured N-terminus of KlebC protrudes beyond the TolC iris, presenting a TonB-box sequence to the periplasm. Association with proton-motive force-linked TonB in the inner membrane drives toxin import through the channel. Finally, we demonstrate that KlebC binding to TolC blocks drug efflux from bacteria. Our results indicate that TolC, in addition to its known role in antibiotic export, can function as a protein import channel for bacteriocins. Bacteria can secrete diffusible protein toxins that kill competing bacteria. Here, the authors use biochemical, biophysical and structural analyses to show how one of these toxins exploits TolC (a major antibiotic efflux channel) to transport itself across the outer membrane of target cells.
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295
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Hopes T, Norris K, Agapiou M, McCarthy CGP, Lewis PA, O'Connell MJ, Fontana J, Aspden JL. Ribosome heterogeneity in Drosophila melanogaster gonads through paralog-switching. Nucleic Acids Res 2021; 50:2240-2257. [PMID: 34283226 PMCID: PMC8887423 DOI: 10.1093/nar/gkab606] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 06/23/2021] [Accepted: 07/02/2021] [Indexed: 12/02/2022] Open
Abstract
Ribosomes have long been thought of as homogeneous macromolecular machines, but recent evidence suggests they are heterogeneous and could be specialised to regulate translation. Here, we have characterised ribosomal protein heterogeneity across 4 tissues of Drosophila melanogaster. We find that testes and ovaries contain the most heterogeneous ribosome populations, which occurs through a combination of paralog-enrichment and paralog-switching. We have solved structures of ribosomes purified from in vivo tissues by cryo-EM, revealing differences in precise ribosomal arrangement for testis and ovary 80S ribosomes. Differences in the amino acid composition of paralog pairs and their localisation on the ribosome exterior indicate paralog-switching could alter the ribosome surface, enabling different proteins to regulate translation. One testis-specific paralog-switching pair is also found in humans, suggesting this is a conserved site of ribosome heterogeneity. Overall, this work allows us to propose that mRNA translation might be regulated in the gonads through ribosome heterogeneity, providing a potential means of ribosome specialisation.
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Affiliation(s)
- Tayah Hopes
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK.,LeedsOmics, University of Leeds, Leeds, UK
| | - Karl Norris
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK.,LeedsOmics, University of Leeds, Leeds, UK.,Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Michaela Agapiou
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK.,LeedsOmics, University of Leeds, Leeds, UK.,Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Charley G P McCarthy
- School of Life Sciences, Faculty of Medicine and Health Sciences, The University of Nottingham, Nottingham NG7 2RD, UK
| | - Philip A Lewis
- School of Cellular and Molecular Medicine, Faculty of Life Sciences, University of Bristol, Bristol BS8 1TD, UK
| | - Mary J O'Connell
- School of Life Sciences, Faculty of Medicine and Health Sciences, The University of Nottingham, Nottingham NG7 2RD, UK
| | - Juan Fontana
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK.,Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Julie L Aspden
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK.,LeedsOmics, University of Leeds, Leeds, UK
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296
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Lilic M, Darst SA, Campbell EA. Structural basis of transcriptional activation by the Mycobacterium tuberculosis intrinsic antibiotic-resistance transcription factor WhiB7. Mol Cell 2021; 81:2875-2886.e5. [PMID: 34171296 PMCID: PMC8311663 DOI: 10.1016/j.molcel.2021.05.017] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 03/22/2021] [Accepted: 05/12/2021] [Indexed: 01/25/2023]
Abstract
In pathogenic mycobacteria, transcriptional responses to antibiotics result in induced antibiotic resistance. WhiB7 belongs to the Actinobacteria-specific family of Fe-S-containing transcription factors and plays a crucial role in inducible antibiotic resistance in mycobacteria. Here, we present cryoelectron microscopy structures of Mycobacterium tuberculosis transcriptional regulatory complexes comprising RNA polymerase σA-holoenzyme, global regulators CarD and RbpA, and WhiB7, bound to a WhiB7-regulated promoter. The structures reveal how WhiB7 interacts with σA-holoenzyme while simultaneously interacting with an AT-rich sequence element via its AT-hook. Evidently, AT-hooks, rare elements in bacteria yet prevalent in eukaryotes, bind to target AT-rich DNA sequences similarly to the nuclear chromosome binding proteins. Unexpectedly, a subset of particles contained a WhiB7-stabilized closed promoter complex, revealing this intermediate's structure, and we apply kinetic modeling and biochemical assays to rationalize how WhiB7 activates transcription. Altogether, our work presents a comprehensive view of how WhiB7 serves to activate gene expression leading to antibiotic resistance.
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Affiliation(s)
- Mirjana Lilic
- Laboratory of Molecular Biophysics, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Seth A Darst
- Laboratory of Molecular Biophysics, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Elizabeth A Campbell
- Laboratory of Molecular Biophysics, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA.
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297
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2.85 and 2.99 Å resolution structures of 110 kDa nitrite reductase determined by 200 kV cryogenic electron microscopy. J Struct Biol 2021; 213:107768. [PMID: 34217801 DOI: 10.1016/j.jsb.2021.107768] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 05/22/2021] [Accepted: 06/28/2021] [Indexed: 11/22/2022]
Abstract
Cu-containing nitrite reductases (NiRs) are 110 kDa enzymes that play central roles in denitrification. Although the NiRs have been well studied, with over 100 Protein Data Bank entries, such issues as crystal packing, photoreduction, and lack of high pH cases have impeded structural analysis of their catalytic mechanisms. Here we show the cryogenic electron microscopy (cryo-EM) structures of Achromobacter cycloclastes NiR (AcNiR) at pH 6.2 and 8.1. The optimization of 3D-reconstruction parameters achieved 2.99 and 2.85 Å resolution. Comprehensive comparisons with cryo-EM and 56 AcNiR crystal structures suggested crystallographic artifacts in residues 185-215 and His255' due to packing and photoreduction, respectively. We used a newly developed map comparison method to detect structural change around the type 2 Cu site. While the theoretical estimation of coordinate errors of cryo-EM structures remains difficult, combined analysis using X-ray and cryo-EM structures will allow deeper insight into the local structural changes of proteins.
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298
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Nadezhdin KD, Neuberger A, Trofimov YA, Krylov NA, Sinica V, Kupko N, Vlachova V, Zakharian E, Efremov RG, Sobolevsky AI. Structural mechanism of heat-induced opening of a temperature-sensitive TRP channel. Nat Struct Mol Biol 2021; 28:564-572. [PMID: 34239124 PMCID: PMC8283911 DOI: 10.1038/s41594-021-00615-4] [Citation(s) in RCA: 63] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 05/28/2021] [Indexed: 02/06/2023]
Abstract
Numerous physiological functions rely on distinguishing temperature through temperature-sensitive transient receptor potential channels (thermo-TRPs). Although the function of thermo-TRPs has been studied extensively, structural determination of their heat- and cold-activated states has remained a challenge. Here, we present cryo-EM structures of the nanodisc-reconstituted wild-type mouse TRPV3 in three distinct conformations: closed, heat-activated sensitized and open states. The heat-induced transformations of TRPV3 are accompanied by changes in the secondary structure of the S2-S3 linker and the N and C termini and represent a conformational wave that links these parts of the protein to a lipid occupying the vanilloid binding site. State-dependent differences in the behavior of bound lipids suggest their active role in thermo-TRP temperature-dependent gating. Our structural data, supported by physiological recordings and molecular dynamics simulations, provide an insight for understanding the molecular mechanism of temperature sensing.
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Affiliation(s)
- Kirill D. Nadezhdin
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, New York, USA
| | - Arthur Neuberger
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, New York, USA
| | - Yuri A. Trofimov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia,National Research Nuclear University Moscow Engineering Physics Institute, Moscow, Russia,Research Center for Molecular Mechanisms of Aging and Age-related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, Russia
| | - Nikolay A. Krylov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia,National Research University Higher School of Economics, Moscow, Russia
| | - Viktor Sinica
- Department of Cellular Neurophysiology, Institute of Physiology Czech Academy of Sciences, Prague, Czech Republic
| | - Nikita Kupko
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, New York, USA
| | - Viktorie Vlachova
- Department of Cellular Neurophysiology, Institute of Physiology Czech Academy of Sciences, Prague, Czech Republic
| | - Eleonora Zakharian
- Department of Cancer Biology & Pharmacology, University of Illinois College of Medicine, Peoria, Illinois, USA
| | - Roman G. Efremov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia,Research Center for Molecular Mechanisms of Aging and Age-related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, Russia,National Research University Higher School of Economics, Moscow, Russia
| | - Alexander I. Sobolevsky
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, New York, USA,Correspondence and requests for materials should be addressed to A.I.S. (; Tel: 212-305-4249)
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299
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Hu M, Yang F, Huang Y, You X, Liu D, Sun S, Sui SF. Structural insights into the mechanism of human NPC1L1-mediated cholesterol uptake. SCIENCE ADVANCES 2021; 7:7/29/eabg3188. [PMID: 34272236 PMCID: PMC8284890 DOI: 10.1126/sciadv.abg3188] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Accepted: 06/03/2021] [Indexed: 05/28/2023]
Abstract
Niemann-Pick C1-like 1 (NPC1L1) protein plays a central role in the intestinal cholesterol absorption and is the target of a drug, ezetimibe, which inhibits NPC1L1 to reduce cholesterol absorption. Here, we present cryo-electron microscopy structures of human NPC1L1 in apo state, cholesterol-enriched state, and ezetimibe-bound state to reveal molecular details of NPC1L1-mediated cholesterol uptake and ezetimibe inhibition. Comparison of these structures reveals that the sterol-sensing domain (SSD) could respond to the cholesterol level alteration by binding different number of cholesterol molecules. Upon increasing cholesterol level, SSD binds more cholesterol molecules, which, in turn, triggers the formation of a stable structural cluster in SSD, while binding of ezetimibe causes the deformation of the SSD and destroys the structural cluster, leading to the inhibition of NPC1L1 function. These results provide insights into mechanisms of NPC1L1 function and ezetimibe action and are of great significance for the development of new cholesterol absorption inhibitors.
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Affiliation(s)
- Miaoqing Hu
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Department of Biology, Southern University of Science and Technology, Shenzhen 518055, Guangdong, China
| | - Fan Yang
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yawen Huang
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Xin You
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Desheng Liu
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Shan Sun
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing 100084, China.
| | - Sen-Fang Sui
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing 100084, China.
- Department of Biology, Southern University of Science and Technology, Shenzhen 518055, Guangdong, China
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300
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Ruan Z, Haley E, Orozco IJ, Sabat M, Myers R, Roth R, Du J, Lü W. Structures of the TRPM5 channel elucidate mechanisms of activation and inhibition. Nat Struct Mol Biol 2021; 28:604-613. [PMID: 34168372 PMCID: PMC8767786 DOI: 10.1038/s41594-021-00607-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 05/12/2021] [Indexed: 02/06/2023]
Abstract
The Ca2+-activated TRPM5 channel plays essential roles in taste perception and insulin secretion. However, the mechanism by which Ca2+ regulates TRPM5 activity remains elusive. We report cryo-EM structures of the zebrafish TRPM5 in an apo closed state, a Ca2+-bound open state, and an antagonist-bound inhibited state. We define two novel ligand binding sites: a Ca2+ site (CaICD) in the intracellular domain and an antagonist site in the transmembrane domain (TMD). The CaICD site is unique to TRPM5 and has two roles: modulating the voltage dependence and promoting Ca2+ binding to the CaTMD site, which is conserved throughout TRPM channels. Conformational changes initialized from both Ca2+ sites cooperatively open the ion-conducting pore. The antagonist NDNA wedges into the space between the S1-S4 domain and pore domain, stabilizing the transmembrane domain in an apo-like closed state. Our results lay the foundation for understanding the voltage-dependent TRPM channels and developing new therapeutic agents.
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Affiliation(s)
- Zheng Ruan
- Van Andel Institute, 333 Bostwick Ave., N.E., Grand Rapids, MI 49503
| | - Emery Haley
- Van Andel Institute, 333 Bostwick Ave., N.E., Grand Rapids, MI 49503
| | - Ian J. Orozco
- Van Andel Institute, 333 Bostwick Ave., N.E., Grand Rapids, MI 49503
| | - Mark Sabat
- Takeda California Inc, 9625 Towne Centre Dr, San Diego, CA 92121
| | - Richard Myers
- Takeda California Inc, 9625 Towne Centre Dr, San Diego, CA 92121
| | - Rebecca Roth
- Van Andel Institute, 333 Bostwick Ave., N.E., Grand Rapids, MI 49503
| | - Juan Du
- Van Andel Institute, 333 Bostwick Ave., N.E., Grand Rapids, MI 49503,CORRESPONDING AUTHOR: Correspondence and requests for materials should be addressed to J. D. () TEL: (616) 234-5358, FAX: 616-234-5170 or W. L. (). TEL: (616) 234-5022, FAX: 616-234-5170
| | - Wei Lü
- Van Andel Institute, 333 Bostwick Ave., N.E., Grand Rapids, MI 49503,CORRESPONDING AUTHOR: Correspondence and requests for materials should be addressed to J. D. () TEL: (616) 234-5358, FAX: 616-234-5170 or W. L. (). TEL: (616) 234-5022, FAX: 616-234-5170
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