551
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Structural Basis of Dot1L Stimulation by Histone H2B Lysine 120 Ubiquitination. Mol Cell 2019; 74:1010-1019.e6. [PMID: 30981630 DOI: 10.1016/j.molcel.2019.03.029] [Citation(s) in RCA: 101] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 03/01/2019] [Accepted: 03/22/2019] [Indexed: 12/31/2022]
Abstract
The essential histone H3 lysine 79 methyltransferase Dot1L regulates transcription and genomic stability and is deregulated in leukemia. The activity of Dot1L is stimulated by mono-ubiquitination of histone H2B on lysine 120 (H2BK120Ub); however, the detailed mechanism is not understood. We report cryo-EM structures of human Dot1L bound to (1) H2BK120Ub and (2) unmodified nucleosome substrates at 3.5 Å and 4.9 Å, respectively. Comparison of both structures, complemented with biochemical experiments, provides critical insights into the mechanism of Dot1L stimulation by H2BK120Ub. Both structures show Dot1L binding to the same extended surface of the histone octamer. In yeast, this surface is used by silencing proteins involved in heterochromatin formation, explaining the mechanism of their competition with Dot1. These results provide a strong foundation for understanding conserved crosstalk between histone modifications found at actively transcribed genes and offer a general model of how ubiquitin might regulate the activity of chromatin enzymes.
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552
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Marabelli C, Marrocco B, Pilotto S, Chittori S, Picaud S, Marchese S, Ciossani G, Forneris F, Filippakopoulos P, Schoehn G, Rhodes D, Subramaniam S, Mattevi A. A Tail-Based Mechanism Drives Nucleosome Demethylation by the LSD2/NPAC Multimeric Complex. Cell Rep 2019; 27:387-399.e7. [PMID: 30970244 DOI: 10.1016/j.celrep.2019.03.061] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 02/28/2019] [Accepted: 03/15/2019] [Indexed: 12/25/2022] Open
Abstract
LSD1 and LSD2 are homologous histone demethylases with opposite biological outcomes related to chromatin silencing and transcription elongation, respectively. Unlike LSD1, LSD2 nucleosome-demethylase activity relies on a specific linker peptide from the multidomain protein NPAC. We used single-particle cryoelectron microscopy (cryo-EM), in combination with kinetic and mutational analysis, to analyze the mechanisms underlying the function of the human LSD2/NPAC-linker/nucleosome complex. Weak interactions between LSD2 and DNA enable multiple binding modes for the association of the demethylase to the nucleosome. The demethylase thereby captures mono- and dimethyl Lys4 of the H3 tail to afford histone demethylation. Our studies also establish that the dehydrogenase domain of NPAC serves as a catalytically inert oligomerization module. While LSD1/CoREST forms a nucleosome docking platform at silenced gene promoters, LSD2/NPAC is a multifunctional enzyme complex with flexible linkers, tailored for rapid chromatin modification, in conjunction with the advance of the RNA polymerase on actively transcribed genes.
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Affiliation(s)
- Chiara Marabelli
- Department of Biology and Biotechnology "Lazzaro Spallanzani," University of Pavia, via Ferrata 9, 27100 Pavia, Italy
| | - Biagina Marrocco
- Department of Biology and Biotechnology "Lazzaro Spallanzani," University of Pavia, via Ferrata 9, 27100 Pavia, Italy
| | - Simona Pilotto
- Department of Biology and Biotechnology "Lazzaro Spallanzani," University of Pavia, via Ferrata 9, 27100 Pavia, Italy
| | - Sagar Chittori
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Sarah Picaud
- Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, Headington, Oxford OX3 7DQ, UK
| | - Sara Marchese
- Department of Biology and Biotechnology "Lazzaro Spallanzani," University of Pavia, via Ferrata 9, 27100 Pavia, Italy
| | - Giuseppe Ciossani
- Department of Biology and Biotechnology "Lazzaro Spallanzani," University of Pavia, via Ferrata 9, 27100 Pavia, Italy
| | - Federico Forneris
- Department of Biology and Biotechnology "Lazzaro Spallanzani," University of Pavia, via Ferrata 9, 27100 Pavia, Italy
| | - Panagis Filippakopoulos
- Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, Headington, Oxford OX3 7DQ, UK
| | - Guy Schoehn
- Institut de Biologie Structurale (IBS), University Grenoble Alpes, CEA, CNRS, 38044 Grenoble, France
| | - Daniela Rhodes
- Institute of Structural Biology, Nanyang Technological University, 59 Nanyang Drive, Singapore 636921, Singapore; School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore; Lee Kong Chian School of Medicine, Nanyang Technological University, 59 Nanyang Drive, Singapore 636921, Singapore
| | - Sriram Subramaniam
- The University of British Columbia, 2215 Wesbrook Mall, Vancouver, BC V6T 1Z3, Canada.
| | - Andrea Mattevi
- Department of Biology and Biotechnology "Lazzaro Spallanzani," University of Pavia, via Ferrata 9, 27100 Pavia, Italy.
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553
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Dong L, Guan X, Li N, Zhang F, Zhu Y, Ren K, Yu L, Zhou F, Han Z, Gao N, Huang Z. An anti-CRISPR protein disables type V Cas12a by acetylation. Nat Struct Mol Biol 2019; 26:308-314. [DOI: 10.1038/s41594-019-0206-1] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 02/21/2019] [Indexed: 01/07/2023]
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554
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De Colibus L, Roine E, Walter TS, Ilca SL, Wang X, Wang N, Roseman AM, Bamford D, Huiskonen JT, Stuart DI. Assembly of complex viruses exemplified by a halophilic euryarchaeal virus. Nat Commun 2019; 10:1456. [PMID: 30926810 PMCID: PMC6441041 DOI: 10.1038/s41467-019-09451-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 03/07/2019] [Indexed: 01/27/2023] Open
Abstract
Many of the largest known viruses belong to the PRD1-adeno structural lineage characterised by conserved pseudo-hexameric capsomers composed of three copies of a single major capsid protein (MCP). Here, by high-resolution cryo-EM analysis, we show that a class of archaeal viruses possess hetero-hexameric MCPs which mimic the PRD1-adeno lineage trimer. These hetero-hexamers are built from heterodimers and utilise a jigsaw-puzzle system of pegs and holes, and underlying minor capsid proteins, to assemble the capsid laterally from the 5-fold vertices. At these vertices proteins engage inwards with the internal membrane vesicle whilst 2-fold symmetric horn-like structures protrude outwards. The horns are assembled from repeated globular domains attached to a central spine, presumably facilitating multimeric attachment to the cell receptor. Such viruses may represent precursors of the main PRD1-adeno lineage, similarly engaging cell-receptors via 5-fold spikes and using minor proteins to define particle size. Here, the authors present the cryo-EM structure of the archaeal virus SH1 at 3.8 Å resolution and show how the major capsid proteins assemble into hetero-hexamers, providing insights into the assembly process of this and related PRD1-adeno lineage viruses.
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Affiliation(s)
- Luigi De Colibus
- Division of Structural Biology, University of Oxford, Wellcome Centre for Human Genetics, Oxford, OX3 7BN, UK
| | - Elina Roine
- Research Program in Molecular and Integrative Biosciences, Faculty of Environmental and Biological Sciences, University of Helsinki, 00014, Helsinki, Finland
| | - Thomas S Walter
- Division of Structural Biology, University of Oxford, Wellcome Centre for Human Genetics, Oxford, OX3 7BN, UK
| | - Serban L Ilca
- Division of Structural Biology, University of Oxford, Wellcome Centre for Human Genetics, Oxford, OX3 7BN, UK
| | - Xiangxi Wang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China
| | - Nan Wang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China
| | - Alan M Roseman
- Division of Molecular & Cellular Function, School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, The Michael Smith Building, Oxford Road, Manchester, M13 9PL, UK
| | - Dennis Bamford
- Research Program in Molecular and Integrative Biosciences, Faculty of Environmental and Biological Sciences, University of Helsinki, 00014, Helsinki, Finland
| | - Juha T Huiskonen
- Division of Structural Biology, University of Oxford, Wellcome Centre for Human Genetics, Oxford, OX3 7BN, UK. .,Research Program in Molecular and Integrative Biosciences, Faculty of Environmental and Biological Sciences, University of Helsinki, 00014, Helsinki, Finland. .,Helsinki Institute of Life Science HiLIFE, University of Helsinki, 00014, Helsinki, Finland.
| | - David I Stuart
- Division of Structural Biology, University of Oxford, Wellcome Centre for Human Genetics, Oxford, OX3 7BN, UK. .,Diamond Light Source Ltd, Harwell Science & Innovation Campus, Didcot, OX11 0DE, UK.
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555
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Abstract
Cryogenic electron microscopy (cryo-EM) enables structure determination of macromolecular objects and their assemblies. Although the techniques have been developing for nearly four decades, they have gained widespread attention in recent years due to technical advances on numerous fronts, enabling traditional microscopists to break into the world of molecular structural biology. Many samples can now be routinely analyzed at near-atomic resolution using standard imaging and image analysis techniques. However, numerous challenges to conventional workflows remain, and continued technical advances open entirely novel opportunities for discovery and exploration. Here, I will review some of the main methods surrounding cryo-EM with an emphasis specifically on single-particle analysis, and I will highlight challenges, open questions, and opportunities for methodology development.
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Affiliation(s)
- Dmitry Lyumkis
- From the Laboratory of Genetics and Helmsley Center for Genomic Medicine, The Salk Institute for Biological Studies, La Jolla, California 92037
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556
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Chen CY, Chang YC, Lin BL, Lin KF, Huang CH, Hsieh DL, Ko TP, Tsai MD. Use of Cryo-EM To Uncover Structural Bases of pH Effect and Cofactor Bispecificity of Ketol-Acid Reductoisomerase. J Am Chem Soc 2019; 141:6136-6140. [DOI: 10.1021/jacs.9b01354] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Chin-Yu Chen
- Department of Life Sciences, National Central University, Taoyuan 32001, Taiwan
| | | | | | - Kuan-Fu Lin
- Department of Life Sciences, National Central University, Taoyuan 32001, Taiwan
| | - Chun-Hsiang Huang
- Experimental Facility Division, National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
| | - Dong-Lin Hsieh
- Department of Life Sciences, National Central University, Taoyuan 32001, Taiwan
| | | | - Ming-Daw Tsai
- Institute of Biochemical Sciences, National Taiwan University, Taipei 106, Taiwan
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557
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Li K, Sun C, Klose T, Irimia-Dominguez J, Vago FS, Vidal R, Jiang W. Sub-3 Å apoferritin structure determined with full range of phase shifts using a single position of volta phase plate. J Struct Biol 2019; 206:225-232. [PMID: 30928614 DOI: 10.1016/j.jsb.2019.03.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Revised: 03/19/2019] [Accepted: 03/22/2019] [Indexed: 01/06/2023]
Abstract
Volta Phase Plate (VPP) has become an invaluable tool for cryo-EM structural determination of small protein complexes by increasing image contrast. Currently, the standard protocol of VPP usage periodically changes the VPP position to a fresh spot during data collection. Such a protocol was to target the phase shifts to a relatively narrow range (around 90°) based on the observations of increased phase shifts and image blur associated with more images taken with a single VPP position. Here, we report a 2.87 Å resolution structure of apoferritin reconstructed from a dataset collected using only a single position of VPP. The reconstruction resolution and map density features are nearly identical to the reconstruction from the control dataset collected with periodic change of VPP positions. Further experiments have verified that similar results, including a 2.5 Å resolution structure, could be obtained with a full range of phase shifts, different spots of variable phase shift increasing rates, and at different ages of the VPP post-installation. Furthermore, we have found that the phase shifts at low resolutions, probably related to the finite size of the Volta spots, could not be correctly modeled by current CTF model using a constant phase shift at all frequencies. In dataset III, severe beam tilt issue was identified but could be computationally corrected with iterative refinements. The observations in this study may provide new insights into further improvement of both the efficiency and robustness of VPP, and to help turn VPP into a plug-and-play device for high-resolution cryo-EM.
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Affiliation(s)
- Kunpeng Li
- Department of Biological Sciences, Markey Center for Structural Biology, Purdue University, West Lafayette, IN 47906, USA
| | - Chen Sun
- Department of Biological Sciences, Markey Center for Structural Biology, Purdue University, West Lafayette, IN 47906, USA
| | - Thomas Klose
- Department of Biological Sciences, Markey Center for Structural Biology, Purdue University, West Lafayette, IN 47906, USA
| | - Jose Irimia-Dominguez
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Frank S Vago
- Department of Biological Sciences, Markey Center for Structural Biology, Purdue University, West Lafayette, IN 47906, USA
| | - Ruben Vidal
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Wen Jiang
- Department of Biological Sciences, Markey Center for Structural Biology, Purdue University, West Lafayette, IN 47906, USA.
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558
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Clairfeuille T, Cloake A, Infield DT, Llongueras JP, Arthur CP, Li ZR, Jian Y, Martin-Eauclaire MF, Bougis PE, Ciferri C, Ahern CA, Bosmans F, Hackos DH, Rohou A, Payandeh J. Structural basis of α-scorpion toxin action on Na v channels. Science 2019; 363:science.aav8573. [PMID: 30733386 DOI: 10.1126/science.aav8573] [Citation(s) in RCA: 111] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 01/28/2019] [Indexed: 01/25/2023]
Abstract
Fast inactivation of voltage-gated sodium (Nav) channels is essential for electrical signaling, but its mechanism remains poorly understood. Here we determined the structures of a eukaryotic Nav channel alone and in complex with a lethal α-scorpion toxin, AaH2, by electron microscopy, both at 3.5-angstrom resolution. AaH2 wedges into voltage-sensing domain IV (VSD4) to impede fast activation by trapping a deactivated state in which gating charge interactions bridge to the acidic intracellular carboxyl-terminal domain. In the absence of AaH2, the S4 helix of VSD4 undergoes a ~13-angstrom translation to unlatch the intracellular fast-inactivation gating machinery. Highlighting the polypharmacology of α-scorpion toxins, AaH2 also targets an unanticipated receptor site on VSD1 and a pore glycan adjacent to VSD4. Overall, this work provides key insights into fast inactivation, electromechanical coupling, and pathogenic mutations in Nav channels.
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Affiliation(s)
- Thomas Clairfeuille
- Department of Structural Biology, Genentech Inc., South San Francisco, CA, USA
| | - Alexander Cloake
- Department of Structural Biology, Genentech Inc., South San Francisco, CA, USA.,Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Daniel T Infield
- Department of Molecular Physiology and Biophysics, The University of Iowa, Iowa City, IA, USA
| | - José P Llongueras
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | | | - Zhong Rong Li
- Department of Biomolecular Resources, Genentech Inc., South San Francisco, CA, USA
| | - Yuwen Jian
- Department of Neuroscience, Genentech Inc., South San Francisco, CA, USA
| | | | - Pierre E Bougis
- Aix Marseille Université, CNRS, LNC, UMR 7291, 13003 Marseille, France
| | - Claudio Ciferri
- Department of Structural Biology, Genentech Inc., South San Francisco, CA, USA
| | - Christopher A Ahern
- Department of Molecular Physiology and Biophysics, The University of Iowa, Iowa City, IA, USA.
| | - Frank Bosmans
- Department of Basic and Applied Medical Sciences, Ghent University, 9000 Ghent, Belgium.
| | - David H Hackos
- Department of Neuroscience, Genentech Inc., South San Francisco, CA, USA.
| | - Alexis Rohou
- Department of Structural Biology, Genentech Inc., South San Francisco, CA, USA.
| | - Jian Payandeh
- Department of Structural Biology, Genentech Inc., South San Francisco, CA, USA.
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559
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Ognjenović J, Grisshammer R, Subramaniam S. Frontiers in Cryo Electron Microscopy of Complex Macromolecular Assemblies. Annu Rev Biomed Eng 2019; 21:395-415. [PMID: 30892930 DOI: 10.1146/annurev-bioeng-060418-052453] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In recent years, cryo electron microscopy (cryo-EM) technology has been transformed with the development of better instrumentation, direct electron detectors, improved methods for specimen preparation, and improved software for data analysis. Analyses using single-particle cryo-EM methods have enabled determination of structures of proteins with sizes smaller than 100 kDa and resolutions of ∼2 Å in some cases. The use of electron tomography combined with subvolume averaging is beginning to allow the visualization of macromolecular complexes in their native environment in unprecedented detail. As a result of these advances, solutions to many intractable challenges in structural and cell biology, such as analysis of highly dynamic soluble and membrane-embedded protein complexes or partially ordered protein aggregates, are now within reach. Recent reports of structural studies of G protein-coupled receptors, spliceosomes, and fibrillar specimens illustrate the progress that has been made using cryo-EM methods, and are the main focus of this review.
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Affiliation(s)
- Jana Ognjenović
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20814, USA; ,
| | - Reinhard Grisshammer
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20814, USA; ,
| | - Sriram Subramaniam
- University of British Columbia, Vancouver, British Columbia V6T 1Z2, Canada;
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560
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Montemiglio LC, Testi C, Ceci P, Falvo E, Pitea M, Savino C, Arcovito A, Peruzzi G, Baiocco P, Mancia F, Boffi A, des Georges A, Vallone B. Cryo-EM structure of the human ferritin-transferrin receptor 1 complex. Nat Commun 2019; 10:1121. [PMID: 30850661 PMCID: PMC6408514 DOI: 10.1038/s41467-019-09098-w] [Citation(s) in RCA: 82] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 02/13/2019] [Indexed: 12/31/2022] Open
Abstract
Human transferrin receptor 1 (CD71) guarantees iron supply by endocytosis upon binding of iron-loaded transferrin and ferritin. Arenaviruses and the malaria parasite exploit CD71 for cell invasion and epitopes on CD71 for interaction with transferrin and pathogenic hosts were identified. Here, we provide the molecular basis of the CD71 ectodomain-human ferritin interaction by determining the 3.9 Å resolution single-particle cryo-electron microscopy structure of their complex and by validating our structural findings in a cellular context. The contact surfaces between the heavy-chain ferritin and CD71 largely overlap with arenaviruses and Plasmodium vivax binding regions in the apical part of the receptor ectodomain. Our data account for transferrin-independent binding of ferritin to CD71 and suggest that select pathogens may have adapted to enter cells by mimicking the ferritin access gate. The human transferrin receptor 1 (CD71) is a transmembrane protein responsible for iron uptake. Here the authors present the 3.9 Å resolution cryo-EM structure of the CD71 ectodomain-human ferritin (H-Ft) complex and find that H-Ft binds a CD71 region different from the transferrin one that overlaps with the surface recognized by select pathogens.
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Affiliation(s)
- Linda Celeste Montemiglio
- Department of Biochemical Sciences "Alessandro Rossi Fanelli", Sapienza University of Rome, P.le A. Moro 5, 00185, Rome, Italy.,Institute of Molecular Biology and Pathology, National Research Council, P.le A. Moro 5, 00185, Rome, Italy.,Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Sapienza Università di Roma, P.le A. Moro 5, 00185, Rome, Italy
| | - Claudia Testi
- Department of Biochemical Sciences "Alessandro Rossi Fanelli", Sapienza University of Rome, P.le A. Moro 5, 00185, Rome, Italy.,Center for Life Nano Science @ Sapienza, Istituto Italiano di Tecnologia, V.le Regina Elena 291, 00161, Rome, Italy
| | - Pierpaolo Ceci
- Institute of Molecular Biology and Pathology, National Research Council, P.le A. Moro 5, 00185, Rome, Italy
| | - Elisabetta Falvo
- Institute of Molecular Biology and Pathology, National Research Council, P.le A. Moro 5, 00185, Rome, Italy
| | - Martina Pitea
- Department of Biochemical Sciences "Alessandro Rossi Fanelli", Sapienza University of Rome, P.le A. Moro 5, 00185, Rome, Italy
| | - Carmelinda Savino
- Institute of Molecular Biology and Pathology, National Research Council, P.le A. Moro 5, 00185, Rome, Italy
| | - Alessandro Arcovito
- Istituto di Biochimica e Biochimica Clinica, Università Cattolica del Sacro Cuore, Largo F. Vito 1, 00168, Rome, Italy.,Fondazione Policlinico Universitario Agostino Gemelli-IRCCS, Largo F. Vito 1, 00168, Rome, Italy
| | - Giovanna Peruzzi
- Center for Life Nano Science @ Sapienza, Istituto Italiano di Tecnologia, V.le Regina Elena 291, 00161, Rome, Italy
| | - Paola Baiocco
- Center for Life Nano Science @ Sapienza, Istituto Italiano di Tecnologia, V.le Regina Elena 291, 00161, Rome, Italy
| | - Filippo Mancia
- Department of Physiology and Cellular Biophysics, Russ Berrie Pavilion, Columbia University Medical Center, 1150 St Nicholas Ave, New York, NY, 10032, USA
| | - Alberto Boffi
- Department of Biochemical Sciences "Alessandro Rossi Fanelli", Sapienza University of Rome, P.le A. Moro 5, 00185, Rome, Italy
| | - Amédée des Georges
- Advanced Science Research Center at The Graduate Center of the City University of New York, 85 Saint Nicholas Terrace, New York, NY, 10031, USA. .,Department of Chemistry and Biochemistry, City College of New York, New York, NY, 10031, USA. .,Programs in Biochemistry and Chemistry, The Graduate Center of the City University of New York, New York, NY, 10016, USA.
| | - Beatrice Vallone
- Department of Biochemical Sciences "Alessandro Rossi Fanelli", Sapienza University of Rome, P.le A. Moro 5, 00185, Rome, Italy. .,Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Sapienza Università di Roma, P.le A. Moro 5, 00185, Rome, Italy.
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561
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Worden EJ, Hoffmann NA, Hicks CW, Wolberger C. Mechanism of Cross-talk between H2B Ubiquitination and H3 Methylation by Dot1L. Cell 2019; 176:1490-1501.e12. [PMID: 30765112 PMCID: PMC6498860 DOI: 10.1016/j.cell.2019.02.002] [Citation(s) in RCA: 157] [Impact Index Per Article: 31.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 01/22/2019] [Accepted: 02/01/2019] [Indexed: 12/21/2022]
Abstract
Methylation of histone H3 K79 by Dot1L is a hallmark of actively transcribed genes that depends on monoubiquitination of H2B K120 (H2B-Ub) and is an example of histone modification cross-talk that is conserved from yeast to humans. We report here cryo-EM structures of Dot1L bound to ubiquitinated nucleosome that show how H2B-Ub stimulates Dot1L activity and reveal a role for the histone H4 tail in positioning Dot1L. We find that contacts mediated by Dot1L and the H4 tail induce a conformational change in the globular core of histone H3 that reorients K79 from an inaccessible position, thus enabling this side chain to insert into the active site in a position primed for catalysis. Our study provides a comprehensive mechanism of cross-talk between histone ubiquitination and methylation and reveals structural plasticity in histones that makes it possible for histone-modifying enzymes to access residues within the nucleosome core.
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Affiliation(s)
- Evan J Worden
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Niklas A Hoffmann
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Chad W Hicks
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Cynthia Wolberger
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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562
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de Ruiter MV, Klem R, Luque D, Cornelissen JJLM, Castón JR. Structural nanotechnology: three-dimensional cryo-EM and its use in the development of nanoplatforms for in vitro catalysis. NANOSCALE 2019; 11:4130-4146. [PMID: 30793729 DOI: 10.1039/c8nr09204d] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The organization of enzymes into different subcellular compartments is essential for correct cell function. Protein-based cages are a relatively recently discovered subclass of structurally dynamic cellular compartments that can be mimicked in the laboratory to encapsulate enzymes. These synthetic structures can then be used to improve our understanding of natural protein-based cages, or as nanoreactors in industrial catalysis, metabolic engineering, and medicine. Since the function of natural protein-based cages is related to their three-dimensional structure, it is important to determine this at the highest possible resolution if viable nanoreactors are to be engineered. Cryo-electron microscopy (cryo-EM) is ideal for undertaking such analyses within a feasible time frame and at near-native conditions. This review describes how three-dimensional cryo-EM is used in this field and discusses its advantages. An overview is also given of the nanoreactors produced so far, their structure, function, and applications.
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Affiliation(s)
- Mark V de Ruiter
- Department of Biomolecular Nanotechnology, MESA+ Institute for Nanotechnology, University of Twente, 7500 AE Enschede, The Netherlands.
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563
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Brown ZP, Takagi J. Advances in domain and subunit localization technology for electron microscopy. Biophys Rev 2019; 11:149-155. [PMID: 30834502 DOI: 10.1007/s12551-019-00513-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Accepted: 02/20/2019] [Indexed: 12/26/2022] Open
Abstract
The award of the 2017 Nobel Prize in chemistry, 'for developing cryo-electron microscopy for the high-resolution structure determination of biomolecules in solution', was recognition that this method, and electron microscopy more generally, represent powerful techniques in the scientific armamentarium for atomic level structural assessment. Technical advances in equipment, software, and sample preparation, have allowed for high-resolution structural determination of a range of complex biological machinery such that the position of individual atoms within these mega-structures can be determined. However, not all targets are amenable to attaining such high-resolution structures and some may only be resolved at so-called intermediate resolutions. In these cases, other tools are needed to correctly characterize the domain or subunit orientation and architecture. In this review, we will outline various methods that can provide additional information to help understand the macro-level organization of proteins/biomolecular complexes when high-resolution structural description is not available. In particular, we will discuss the recent development and use of a novel protein purification approach, known as the the PA tag/NZ-1 antibody system, which provides numberous beneficial properties, when used in electron microscopy experimentation.
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Affiliation(s)
- Zuben P Brown
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA.
| | - Junichi Takagi
- Laboratory of Protein Synthesis and Expression, Institute for Protein Research, Osaka University, Osaka, Japan
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564
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Structural basis for KCTD-mediated rapid desensitization of GABA B signalling. Nature 2019; 567:127-131. [PMID: 30814734 PMCID: PMC6405316 DOI: 10.1038/s41586-019-0990-0] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 01/24/2019] [Indexed: 11/23/2022]
Abstract
The GABAB receptor is one of the principal inhibitory neurotransmitter receptors in the brain, and it signals through heterotrimeric G proteins to activate a variety of effectors including G protein-coupled inwardly-rectifying potassium channels (GIRKs)1,2. GABAB receptor signaling is tightly regulated by auxiliary subunits called KCTDs, which control the kinetics of GIRK activation and desensitization3–5. However, the mechanistic basis for KCTD modulation of GABAB signaling remains incompletely understood. Here, using a combination of X-ray crystallography, electron microscopy, functional and biochemical experiments we reveal the molecular details of KCTD binding to both GABAB receptors and Gβγ subunits. KCTDs associate with the receptor by forming an asymmetric pentameric ring around a region of the receptor C-terminal tail, while a second KCTD domain, H1, engages in a symmetric interaction with five copies of Gβγ in which the G protein subunits also directly interact with one another. We further show that KCTD binding to Gβγ is highly cooperative, defining a model in which KCTDs cooperatively strip G proteins from GIRK channels to induce rapid desensitization following receptor activation. These results provide a framework for understanding the molecular basis for the precise temporal control of GABAB signaling by KCTD proteins.
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565
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Automatic detection, localization and segmentation of nano-particles with deep learning in microscopy images. Micron 2019; 120:113-119. [PMID: 30844638 DOI: 10.1016/j.micron.2019.02.009] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 02/19/2019] [Accepted: 02/20/2019] [Indexed: 12/29/2022]
Abstract
With the growing amount of high resolution microscopy images automatic nano-particle detection, shape analysis and size determination have gained importance for providing quantitative support that gives important information for the evaluation of the material. In this paper, we present a new method for detection of nano-particles and determination of their shapes and sizes simultaneously with deep learning. The proposed method employs multiple output convolutional neural networks (MO-CNN) and has two outputs: first is the detection output that gives the locations of the particles and the other one is the segmentation output for providing the boundaries of the nano-particles. The final sizes of particles are determined with the modified Hough algorithm that runs on the segmentation output. The proposed method is tested and evaluated on a dataset containing 17 TEM images of Fe3O4 and silica coated nano-particles. Also, we compared these results with U-net algorithm which is a popular deep learning method. The experiments showed that the proposed method has 98.23% accuracy for detection and 96.59% accuracy for segmentation of nano-particles.
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566
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Gulati S, Palczewski K, Engel A, Stahlberg H, Kovacik L. Cryo-EM structure of phosphodiesterase 6 reveals insights into the allosteric regulation of type I phosphodiesterases. SCIENCE ADVANCES 2019; 5:eaav4322. [PMID: 30820458 PMCID: PMC6392808 DOI: 10.1126/sciadv.aav4322] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 01/14/2019] [Indexed: 05/27/2023]
Abstract
Cyclic nucleotide phosphodiesterases (PDEs) work in conjunction with adenylate/guanylate cyclases to regulate the key second messengers of G protein-coupled receptor signaling. Previous attempts to determine the full-length structure of PDE family members at high-resolution have been hindered by structural flexibility, especially in their linker regions and N- and C-terminal ends. Therefore, most structure-activity relationship studies have so far focused on truncated and conserved catalytic domains rather than the regulatory domains that allosterically govern the activity of most PDEs. Here, we used single-particle cryo-electron microscopy to determine the structure of the full-length PDE6αβ2γ complex. The final density map resolved at 3.4 Å reveals several previously unseen structural features, including a coiled N-terminal domain and the interface of PDE6γ subunits with the PDE6αβ heterodimer. Comparison of the PDE6αβ2γ complex with the closed state of PDE2A sheds light on the conformational changes associated with the allosteric activation of type I PDEs.
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Affiliation(s)
- Sahil Gulati
- Gavin Herbert Eye Institute and the Department of Ophthalmology, University of California, Irvine, 829 Health Sciences Road, Irvine, CA 92617, USA
- Department of Pharmacology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
- Cleveland Center for Membrane and Structural Biology, Case Western Reserve University, 1819 East 101st Street, Cleveland, OH 44106, USA
| | - Krzysztof Palczewski
- Gavin Herbert Eye Institute and the Department of Ophthalmology, University of California, Irvine, 829 Health Sciences Road, Irvine, CA 92617, USA
- Department of Pharmacology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
- Cleveland Center for Membrane and Structural Biology, Case Western Reserve University, 1819 East 101st Street, Cleveland, OH 44106, USA
| | - Andreas Engel
- Center for Cellular Imaging and NanoAnalytics, Biozentrum, University of Basel, Mattenstrasse 26, 4058 Basel, Switzerland
| | - Henning Stahlberg
- Center for Cellular Imaging and NanoAnalytics, Biozentrum, University of Basel, Mattenstrasse 26, 4058 Basel, Switzerland
| | - Lubomir Kovacik
- Center for Cellular Imaging and NanoAnalytics, Biozentrum, University of Basel, Mattenstrasse 26, 4058 Basel, Switzerland
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567
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Capabilities of the Falcon III detector for single-particle structure determination. Ultramicroscopy 2019; 203:145-154. [PMID: 30738626 DOI: 10.1016/j.ultramic.2019.01.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 01/10/2019] [Accepted: 01/26/2019] [Indexed: 02/02/2023]
Abstract
Direct electron detectors are an essential asset for the resolution revolution in electron cryo microscopy of biological objects. The direct detectors provide two modes of data acquisition; the counting mode in which single electrons are counted, and the integrating mode in which the signal that arises from the incident electrons is integrated. While counting mode leads to far higher detective quantum efficiency at all spatial frequencies, the integrating mode enables faster data acquisition at higher exposure rates. For optimal throughput at best possible resolution it is important to understand when the better performance in counting mode becomes essential for solving a structure and when the lower detective quantum efficiency in integrating mode can be compensated by increasing the number of particles in the data set. Here, we provide a case study of the Falcon III camera, which has counting mode capability at exposure rates of <0.9 e-/Px² and integrating mode capability at exposure rates above 10 e-/Px². We found that counting mode gives better resolution for medium sized complexes such as the β-galactosidase (465 kDa) (2.2 Å, 97% of Nyquist vs. 2.4 Å, 89% of Nyquist) with data sets of similar size. However, for larger particles such as Hepatitis B virus capsid like particles (4.8 MDa) we did not find any resolution gain in counting mode.
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568
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Xu H, Li T, Rohou A, Arthur CP, Tzakoniati F, Wong E, Estevez A, Kugel C, Franke Y, Chen J, Ciferri C, Hackos DH, Koth CM, Payandeh J. Structural Basis of Nav1.7 Inhibition by a Gating-Modifier Spider Toxin. Cell 2019; 176:702-715.e14. [PMID: 30661758 DOI: 10.1016/j.cell.2018.12.018] [Citation(s) in RCA: 112] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 09/11/2018] [Accepted: 12/11/2018] [Indexed: 12/19/2022]
Abstract
Voltage-gated sodium (Nav) channels are targets of disease mutations, toxins, and therapeutic drugs. Despite recent advances, the structural basis of voltage sensing, electromechanical coupling, and toxin modulation remains ill-defined. Protoxin-II (ProTx2) from the Peruvian green velvet tarantula is an inhibitor cystine-knot peptide and selective antagonist of the human Nav1.7 channel. Here, we visualize ProTx2 in complex with voltage-sensor domain II (VSD2) from Nav1.7 using X-ray crystallography and cryoelectron microscopy. Membrane partitioning orients ProTx2 for unfettered access to VSD2, where ProTx2 interrogates distinct features of the Nav1.7 receptor site. ProTx2 positions two basic residues into the extracellular vestibule to antagonize S4 gating-charge movement through an electrostatic mechanism. ProTx2 has trapped activated and deactivated states of VSD2, revealing a remarkable ∼10 Å translation of the S4 helix, providing a structural framework for activation gating in voltage-gated ion channels. Finally, our results deliver key templates to design selective Nav channel antagonists.
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Affiliation(s)
- Hui Xu
- Department of Structural Biology, Genentech, South San Francisco, CA 94080, USA
| | - Tianbo Li
- Department of Biochemical and Cellular Pharmacology, Genentech, South San Francisco, CA 94080, USA.
| | - Alexis Rohou
- Department of Structural Biology, Genentech, South San Francisco, CA 94080, USA.
| | | | - Foteini Tzakoniati
- Department of Structural Biology, Genentech, South San Francisco, CA 94080, USA
| | - Evera Wong
- Department of Neuroscience, Genentech, South San Francisco, CA 94080, USA
| | - Alberto Estevez
- Department of Structural Biology, Genentech, South San Francisco, CA 94080, USA
| | - Christine Kugel
- Department of Biomolecular Resources, Genentech, South San Francisco, CA 94080, USA
| | - Yvonne Franke
- Department of Biomolecular Resources, Genentech, South San Francisco, CA 94080, USA
| | - Jun Chen
- Department of Biochemical and Cellular Pharmacology, Genentech, South San Francisco, CA 94080, USA
| | - Claudio Ciferri
- Department of Structural Biology, Genentech, South San Francisco, CA 94080, USA
| | - David H Hackos
- Department of Neuroscience, Genentech, South San Francisco, CA 94080, USA.
| | - Christopher M Koth
- Department of Structural Biology, Genentech, South San Francisco, CA 94080, USA.
| | - Jian Payandeh
- Department of Structural Biology, Genentech, South San Francisco, CA 94080, USA.
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569
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Miller AN, Vaisey G, Long SB. Molecular mechanisms of gating in the calcium-activated chloride channel bestrophin. eLife 2019; 8:43231. [PMID: 30628889 PMCID: PMC6342527 DOI: 10.7554/elife.43231] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 01/02/2019] [Indexed: 11/13/2022] Open
Abstract
Bestrophin (BEST1-4) ligand-gated chloride (Cl-) channels are activated by calcium (Ca2+). Mutation of BEST1 causes retinal disease. Partly because bestrophin channels have no sequence or structural similarity to other ion channels, the molecular mechanisms underlying gating are unknown. Here, we present a series of cryo-electron microscopy structures of chicken BEST1, determined at 3.1 Å resolution or better, that represent the channel’s principal gating states. Unlike other channels, opening of the pore is due to the repositioning of tethered pore-lining helices within a surrounding protein shell that dramatically widens a neck of the pore through a concertina of amino acid rearrangements. The neck serves as both the activation and the inactivation gate. Ca2+ binding instigates opening of the neck through allosteric means whereas inactivation peptide binding induces closing. An aperture within the otherwise wide pore controls anion permeability. The studies define a new molecular paradigm for gating among ligand-gated ion channels.
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Affiliation(s)
- Alexandria N Miller
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, United States
| | - George Vaisey
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, United States.,Louis V. Gerstner Jr. Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, United States
| | - Stephen B Long
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, United States
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570
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Krishna Kumar K, Shalev-Benami M, Robertson MJ, Hu H, Banister SD, Hollingsworth SA, Latorraca NR, Kato HE, Hilger D, Maeda S, Weis WI, Farrens DL, Dror RO, Malhotra SV, Kobilka BK, Skiniotis G. Structure of a Signaling Cannabinoid Receptor 1-G Protein Complex. Cell 2019; 176:448-458.e12. [PMID: 30639101 DOI: 10.1016/j.cell.2018.11.040] [Citation(s) in RCA: 283] [Impact Index Per Article: 56.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 10/16/2018] [Accepted: 11/26/2018] [Indexed: 12/14/2022]
Abstract
Cannabis elicits its mood-enhancing and analgesic effects through the cannabinoid receptor 1 (CB1), a G protein-coupled receptor (GPCR) that signals primarily through the adenylyl cyclase-inhibiting heterotrimeric G protein Gi. Activation of CB1-Gi signaling pathways holds potential for treating a number of neurological disorders and is thus crucial to understand the mechanism of Gi activation by CB1. Here, we present the structure of the CB1-Gi signaling complex bound to the highly potent agonist MDMB-Fubinaca (FUB), a recently emerged illicit synthetic cannabinoid infused in street drugs that have been associated with numerous overdoses and fatalities. The structure illustrates how FUB stabilizes the receptor in an active state to facilitate nucleotide exchange in Gi. The results compose the structural framework to explain CB1 activation by different classes of ligands and provide insights into the G protein coupling and selectivity mechanisms adopted by the receptor.
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Affiliation(s)
- Kaavya Krishna Kumar
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 279 Campus Drive, Stanford, CA 94305, USA
| | - Moran Shalev-Benami
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 279 Campus Drive, Stanford, CA 94305, USA; Department of Structural Biology, Stanford University School of Medicine, 279 Campus Drive, Stanford, CA 94305, USA
| | - Michael J Robertson
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 279 Campus Drive, Stanford, CA 94305, USA; Department of Structural Biology, Stanford University School of Medicine, 279 Campus Drive, Stanford, CA 94305, USA
| | - Hongli Hu
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 279 Campus Drive, Stanford, CA 94305, USA; Department of Structural Biology, Stanford University School of Medicine, 279 Campus Drive, Stanford, CA 94305, USA
| | - Samuel D Banister
- Department of Radiation Oncology, Division of Radiation and Cancer Biology, Stanford University School of Medicine, Stanford, CA 94304, USA
| | - Scott A Hollingsworth
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 279 Campus Drive, Stanford, CA 94305, USA; Department of Computer Science, Stanford University, Stanford, CA 94305, USA; Biophysics Program, Stanford University, Stanford, CA 94305, USA
| | - Naomi R Latorraca
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 279 Campus Drive, Stanford, CA 94305, USA; Department of Computer Science, Stanford University, Stanford, CA 94305, USA; Biophysics Program, Stanford University, Stanford, CA 94305, USA
| | - Hideaki E Kato
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 279 Campus Drive, Stanford, CA 94305, USA
| | - Daniel Hilger
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 279 Campus Drive, Stanford, CA 94305, USA
| | - Shoji Maeda
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 279 Campus Drive, Stanford, CA 94305, USA
| | - William I Weis
- Department of Structural Biology, Stanford University School of Medicine, 279 Campus Drive, Stanford, CA 94305, USA; Department of Photon Science, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, CA 94025, USA
| | - David L Farrens
- Departments of Biochemistry and Molecular Biology, Oregon Health Sciences University, Portland, OR 97201, USA
| | - Ron O Dror
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 279 Campus Drive, Stanford, CA 94305, USA; Department of Computer Science, Stanford University, Stanford, CA 94305, USA; Biophysics Program, Stanford University, Stanford, CA 94305, USA
| | - Sanjay V Malhotra
- Department of Radiation Oncology, Division of Radiation and Cancer Biology, Stanford University School of Medicine, Stanford, CA 94304, USA
| | - Brian K Kobilka
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 279 Campus Drive, Stanford, CA 94305, USA.
| | - Georgios Skiniotis
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 279 Campus Drive, Stanford, CA 94305, USA; Department of Structural Biology, Stanford University School of Medicine, 279 Campus Drive, Stanford, CA 94305, USA; Department of Photon Science, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, CA 94025, USA.
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571
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Özcan A, Pausch P, Linden A, Wulf A, Schühle K, Heider J, Urlaub H, Heimerl T, Bange G, Randau L. Type IV CRISPR RNA processing and effector complex formation in Aromatoleum aromaticum. Nat Microbiol 2019; 4:89-96. [PMID: 30397343 DOI: 10.1038/s41564-018-0274-8] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 09/24/2018] [Indexed: 12/24/2022]
Abstract
Type IV CRISPR-Cas modules belong to class 1 prokaryotic adaptive immune systems, which are defined by the presence of multisubunit effector complexes. They usually lack the known Cas proteins involved in adaptation and target cleavage, and their function has not been experimentally addressed. To investigate RNA and protein components of this CRISPR-Cas type, we located a complete type IV cas gene locus and an adjacent CRISPR array on a megaplasmid of Aromatoleum aromaticum EbN1, which contains an additional type I-C system on its chromosome. RNA sequencing analyses verified CRISPR RNA (crRNA) production and maturation for both systems. Type IV crRNAs were shown to harbour unusually short 7 nucleotide 5'-repeat tags and stable 3' hairpin structures. A unique Cas6 variant (Csf5) was identified that generates crRNAs that are specifically incorporated into type IV CRISPR-ribonucleoprotein (crRNP) complexes. Structures of RNA-bound Csf5 were obtained. Recombinant production and purification of the type IV Cas proteins, together with electron microscopy, revealed that Csf2 acts as a helical backbone for type IV crRNPs that include Csf5, Csf3 and a large subunit (Csf1). Mass spectrometry analyses identified protein-protein and protein-RNA contact sites. These results highlight evolutionary connections between type IV and type I CRISPR-Cas systems and demonstrate that type IV CRISPR-Cas systems employ crRNA-guided effector complexes.
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Affiliation(s)
- Ahsen Özcan
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Patrick Pausch
- LOEWE Center for Synthetic Microbiology (Synmikro), Philipps University Marburg, Marburg, Germany
- Faculty of Chemistry, Philipps-University-Marburg, Marburg, Germany
| | - Andreas Linden
- Bioanalytics Research Group, Department of Clinical Chemistry, University Medical Centre, Göttingen, Germany
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Alexander Wulf
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Karola Schühle
- Laboratory for Microbiology, Department of Biology, Philipps-University Marburg, Marburg, Germany
| | - Johann Heider
- LOEWE Center for Synthetic Microbiology (Synmikro), Philipps University Marburg, Marburg, Germany
- Laboratory for Microbiology, Department of Biology, Philipps-University Marburg, Marburg, Germany
| | - Henning Urlaub
- Bioanalytics Research Group, Department of Clinical Chemistry, University Medical Centre, Göttingen, Germany
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Thomas Heimerl
- LOEWE Center for Synthetic Microbiology (Synmikro), Philipps University Marburg, Marburg, Germany
| | - Gert Bange
- LOEWE Center for Synthetic Microbiology (Synmikro), Philipps University Marburg, Marburg, Germany
- Faculty of Chemistry, Philipps-University-Marburg, Marburg, Germany
| | - Lennart Randau
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany.
- LOEWE Center for Synthetic Microbiology (Synmikro), Philipps University Marburg, Marburg, Germany.
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572
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Sorzano COS, Jiménez A, Mota J, Vilas JL, Maluenda D, Martínez M, Ramírez-Aportela E, Majtner T, Segura J, Sánchez-García R, Rancel Y, del Caño L, Conesa P, Melero R, Jonic S, Vargas J, Cazals F, Freyberg Z, Krieger J, Bahar I, Marabini R, Carazo JM. Survey of the analysis of continuous conformational variability of biological macromolecules by electron microscopy. Acta Crystallogr F Struct Biol Commun 2019; 75:19-32. [PMID: 30605122 PMCID: PMC6317454 DOI: 10.1107/s2053230x18015108] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 10/26/2018] [Indexed: 11/10/2022] Open
Abstract
Single-particle analysis by electron microscopy is a well established technique for analyzing the three-dimensional structures of biological macromolecules. Besides its ability to produce high-resolution structures, it also provides insights into the dynamic behavior of the structures by elucidating their conformational variability. Here, the different image-processing methods currently available to study continuous conformational changes are reviewed.
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Affiliation(s)
| | - A. Jiménez
- National Center of Biotechnology (CSIC), Spain
| | - J. Mota
- National Center of Biotechnology (CSIC), Spain
| | - J. L. Vilas
- National Center of Biotechnology (CSIC), Spain
| | - D. Maluenda
- National Center of Biotechnology (CSIC), Spain
| | - M. Martínez
- National Center of Biotechnology (CSIC), Spain
| | | | - T. Majtner
- National Center of Biotechnology (CSIC), Spain
| | - J. Segura
- National Center of Biotechnology (CSIC), Spain
| | | | - Y. Rancel
- National Center of Biotechnology (CSIC), Spain
| | - L. del Caño
- National Center of Biotechnology (CSIC), Spain
| | - P. Conesa
- National Center of Biotechnology (CSIC), Spain
| | - R. Melero
- National Center of Biotechnology (CSIC), Spain
| | - S. Jonic
- Sorbonne Université, UMR CNRS 7590, Muséum National d’Histoire Naturelle, IRD, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, IMPMC, Paris, France
| | | | - F. Cazals
- Inria Sophia Antipolis – Méditerranée, France
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573
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Arthur CP, Ciferri C. High-Throughput Protein Analysis Using Negative Stain Electron Microscopy and 2D Classification. Methods Mol Biol 2019; 2025:477-485. [PMID: 31267467 DOI: 10.1007/978-1-4939-9624-7_22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
High-throughput protein expression and purification allows for fast triaging of several constructs based on expression levels, protein integrity, and solubility. While this technology has been successfully adopted to prioritize constructs for structural biology, it could not inform on important biochemical properties such as domain architecture, homogeneity, and flexibility. Negative staining electron microscopy can be used to quickly evaluate these properties and, if coupled to single particle analysis, can inform on the architecture and conformational state of nearly any protein sample. Here we describe a protocol for negative stain sample preparation, imaging, and two-dimensional (2D) data analysis applicable to a variety of protein complexes. We discuss in more detail a specific application of this technology to large molecule studies to determine the binding sites of individual antibodies on target antigens.
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Affiliation(s)
- Christopher P Arthur
- Department of Structural Biology, Cryo-EM Unit. 1 DNA Way, MS, Genentech, Inc., South San Francisco, CA, USA.
| | - Claudio Ciferri
- Department of Structural Biology, Cryo-EM Unit. 1 DNA Way, MS, Genentech, Inc., South San Francisco, CA, USA.
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574
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Wong W, Huang R, Menant S, Hong C, Sandow JJ, Birkinshaw RW, Healer J, Hodder AN, Kanjee U, Tonkin CJ, Heckmann D, Soroka V, Søgaard TMM, Jørgensen T, Duraisingh MT, Czabotar PE, de Jongh WA, Tham WH, Webb AI, Yu Z, Cowman AF. Structure of Plasmodium falciparum Rh5-CyRPA-Ripr invasion complex. Nature 2018; 565:118-121. [PMID: 30542156 DOI: 10.1038/s41586-018-0779-6] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Accepted: 10/25/2018] [Indexed: 01/24/2023]
Abstract
Plasmodium falciparum causes the severe form of malaria that has high levels of mortality in humans. Blood-stage merozoites of P. falciparum invade erythrocytes, and this requires interactions between multiple ligands from the parasite and receptors in hosts. These interactions include the binding of the Rh5-CyRPA-Ripr complex with the erythrocyte receptor basigin1,2, which is an essential step for entry into human erythrocytes. Here we show that the Rh5-CyRPA-Ripr complex binds the erythrocyte cell line JK-1 significantly better than does Rh5 alone, and that this binding occurs through the insertion of Rh5 and Ripr into host membranes as a complex with high molecular weight. We report a cryo-electron microscopy structure of the Rh5-CyRPA-Ripr complex at subnanometre resolution, which reveals the organization of this essential invasion complex and the mode of interactions between members of the complex, and shows that CyRPA is a critical mediator of complex assembly. Our structure identifies blades 4-6 of the β-propeller of CyRPA as contact sites for Rh5 and Ripr. The limited contacts between Rh5-CyRPA and CyRPA-Ripr are consistent with the dissociation of Rh5 and Ripr from CyRPA for membrane insertion. A comparision of the crystal structure of Rh5-basigin with the cryo-electron microscopy structure of Rh5-CyRPA-Ripr suggests that Rh5 and Ripr are positioned parallel to the erythrocyte membrane before membrane insertion. This provides information on the function of this complex, and thereby provides insights into invasion by P. falciparum.
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Affiliation(s)
- Wilson Wong
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.,Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Rick Huang
- CryoEM Shared Resources, Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Sebastien Menant
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
| | - Chuan Hong
- CryoEM Shared Resources, Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Jarrod J Sandow
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.,Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Richard W Birkinshaw
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.,Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Julie Healer
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.,Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Anthony N Hodder
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.,Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Usheer Kanjee
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, USA
| | - Christopher J Tonkin
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.,Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Denise Heckmann
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.,Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | | | | | | | - Manoj T Duraisingh
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, USA
| | - Peter E Czabotar
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.,Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | | | - Wai-Hong Tham
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.,Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Andrew I Webb
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.,Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Zhiheng Yu
- CryoEM Shared Resources, Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Alan F Cowman
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia. .,Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia.
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575
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Structural Basis of the Proton Sensitivity of Human GluN1-GluN2A NMDA Receptors. Cell Rep 2018; 25:3582-3590.e4. [DOI: 10.1016/j.celrep.2018.11.071] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 11/01/2018] [Accepted: 11/16/2018] [Indexed: 11/20/2022] Open
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576
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Advances in image processing for single-particle analysis by electron cryomicroscopy and challenges ahead. Curr Opin Struct Biol 2018; 52:127-145. [PMID: 30509756 DOI: 10.1016/j.sbi.2018.11.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 10/26/2018] [Accepted: 11/17/2018] [Indexed: 12/20/2022]
Abstract
Electron cryomicroscopy (cryoEM) is essential for the study and functional understanding of non-crystalline macromolecules such as proteins. These molecules cannot be imaged using X-ray crystallography or other popular methods. CryoEM has been successfully used to visualize macromolecular complexes such as ribosomes, viruses, and ion channels. Determination of structural models of these at various conformational states leads to insight on how these molecules function. Recent advances in imaging technology have given cryoEM a scientific rebirth. As a result of these technological advances image processing and analysis have yielded molecular structures at atomic resolution. Nevertheless there continue to be challenges in image processing, and in this article we will touch on the most essential in order to derive an accurate three-dimensional model from noisy projection images. Traditional approaches, such as k-means clustering for class averaging, will be provided as background. We will then highlight new approaches for each image processing subproblem, including a 3D reconstruction method for asymmetric molecules using just two projection images and deep learning algorithms for automated particle picking.
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577
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Wang L, Fu TM, Zhou Y, Xia S, Greka A, Wu H. Structures and gating mechanism of human TRPM2. Science 2018; 362:science.aav4809. [PMID: 30467180 DOI: 10.1126/science.aav4809] [Citation(s) in RCA: 113] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Accepted: 11/10/2018] [Indexed: 12/11/2022]
Abstract
Transient receptor potential (TRP) melastatin 2 (TRPM2) is a cation channel associated with numerous diseases. It has a C-terminal NUDT9 homology (NUDT9H) domain responsible for binding adenosine diphosphate (ADP)-ribose (ADPR), and both ADPR and calcium (Ca2+) are required for TRPM2 activation. Here we report cryo-electron microscopy structures of human TRPM2 alone, with ADPR, and with ADPR and Ca2+ NUDT9H forms both intra- and intersubunit interactions with the N-terminal TRPM homology region (MHR1/2/3) in the apo state but undergoes conformational changes upon ADPR binding, resulting in rotation of MHR1/2 and disruption of the intersubunit interaction. The binding of Ca2+ further engages transmembrane helices and the conserved TRP helix to cause conformational changes at the MHR arm and the lower gating pore to potentiate channel opening. These findings explain the molecular mechanism of concerted TRPM2 gating by ADPR and Ca2+ and provide insights into the gating mechanism of other TRP channels.
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Affiliation(s)
- Longfei Wang
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA.,Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA
| | - Tian-Min Fu
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA. .,Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA
| | - Yiming Zhou
- Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.,Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Shiyu Xia
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA.,Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA
| | - Anna Greka
- Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.,Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Hao Wu
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA. .,Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA
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578
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Soczek KM, Grant T, Rosenthal PB, Mondragón A. CryoEM structures of open dimers of gyrase A in complex with DNA illuminate mechanism of strand passage. eLife 2018; 7:41215. [PMID: 30457554 PMCID: PMC6286129 DOI: 10.7554/elife.41215] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 11/09/2018] [Indexed: 11/13/2022] Open
Abstract
Gyrase is a unique type IIA topoisomerase that uses ATP hydrolysis to maintain the negatively supercoiled state of bacterial DNA. In order to perform its function, gyrase undergoes a sequence of conformational changes that consist of concerted gate openings, DNA cleavage, and DNA strand passage events. Structures where the transported DNA molecule (T-segment) is trapped by the A subunit have not been observed. Here we present the cryoEM structures of two oligomeric complexes of open gyrase A dimers and DNA. The protein subunits in these complexes were solved to 4 Å and 5.2 Å resolution. One of the complexes traps a linear DNA molecule, a putative T-segment, which interacts with the open gyrase A dimers in two states, representing steps either prior to or after passage through the DNA-gate. The structures locate the T-segment in important intermediate conformations of the catalytic cycle and provide insights into gyrase-DNA interactions and mechanism.
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Affiliation(s)
- Katarzyna M Soczek
- Department of Molecular Biosciences, Northwestern University, Evanston, United States
| | - Tim Grant
- Division of Physical Biochemistry, MRC National Institute for Medical Research, London, United Kingdom
| | - Peter B Rosenthal
- Division of Physical Biochemistry, MRC National Institute for Medical Research, London, United Kingdom.,Structural Biology of Cells and Viruses Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Alfonso Mondragón
- Department of Molecular Biosciences, Northwestern University, Evanston, United States
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579
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Novikova IV, Sharma N, Moser T, Sontag R, Liu Y, Collazo MJ, Cascio D, Shokuhfar T, Hellmann H, Knoblauch M, Evans JE. Protein structural biology using cell-free platform from wheat germ. ADVANCED STRUCTURAL AND CHEMICAL IMAGING 2018; 4:13. [PMID: 30524935 PMCID: PMC6244559 DOI: 10.1186/s40679-018-0062-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 10/31/2018] [Indexed: 12/11/2022]
Abstract
One of the biggest bottlenecks for structural analysis of proteins remains the creation of high-yield and high-purity samples of the target protein. Cell-free protein synthesis technologies are powerful and customizable platforms for obtaining functional proteins of interest in short timeframes, while avoiding potential toxicity issues and permitting high-throughput screening. These methods have benefited many areas of genomic and proteomics research, therapeutics, vaccine development and protein chip constructions. In this work, we demonstrate a versatile and multiscale eukaryotic wheat germ cell-free protein expression pipeline to generate functional proteins of different sizes from multiple host organism and DNA source origins. We also report on a robust purification procedure, which can produce highly pure (> 98%) proteins with no specialized equipment required and minimal time invested. This pipeline successfully produced and analyzed proteins in all three major geometry formats used for structural biology including single particle analysis with electron microscopy, and both two-dimensional and three-dimensional protein crystallography. The flexibility of the wheat germ system in combination with the multiscale pipeline described here provides a new workflow for rapid production and purification of samples that may not be amenable to other recombinant approaches for structural characterization.
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Affiliation(s)
- Irina V. Novikova
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, 3335 Innovation Blvd, Richland, WA 99354 USA
| | - Noopur Sharma
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, 3335 Innovation Blvd, Richland, WA 99354 USA
| | - Trevor Moser
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, 3335 Innovation Blvd, Richland, WA 99354 USA
| | - Ryan Sontag
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, 3335 Innovation Blvd, Richland, WA 99354 USA
| | - Yan Liu
- School of Biological Sciences, Washington State University, Pullman, WA 99164 USA
| | - Michael J. Collazo
- Department of Biological Chemistry, University of California Los Angeles, Howard Hughes Medical Institute, UCLA-DOE Institute for Genomics and Proteomics, Los Angeles, CA 90095 USA
- Department of Chemistry and Biochemistry, University of California Los Angeles, Howard Hughes Medical Institute, UCLA-DOE Institute for Genomics and Proteomics, Los Angeles, CA 90095 USA
| | - Duilio Cascio
- Department of Biological Chemistry, University of California Los Angeles, Howard Hughes Medical Institute, UCLA-DOE Institute for Genomics and Proteomics, Los Angeles, CA 90095 USA
- Department of Chemistry and Biochemistry, University of California Los Angeles, Howard Hughes Medical Institute, UCLA-DOE Institute for Genomics and Proteomics, Los Angeles, CA 90095 USA
| | - Tolou Shokuhfar
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607 USA
| | - Hanjo Hellmann
- School of Biological Sciences, Washington State University, Pullman, WA 99164 USA
| | - Michael Knoblauch
- School of Biological Sciences, Washington State University, Pullman, WA 99164 USA
| | - James E. Evans
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, 3335 Innovation Blvd, Richland, WA 99354 USA
- School of Biological Sciences, Washington State University, Pullman, WA 99164 USA
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580
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Zivanov J, Nakane T, Forsberg BO, Kimanius D, Hagen WJ, Lindahl E, Scheres SH. New tools for automated high-resolution cryo-EM structure determination in RELION-3. eLife 2018; 7:42166. [PMID: 30412051 PMCID: PMC6250425 DOI: 10.7554/elife.42166] [Citation(s) in RCA: 3197] [Impact Index Per Article: 532.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 11/06/2018] [Indexed: 12/28/2022] Open
Abstract
Here, we describe the third major release of RELION. CPU-based vector acceleration has been added in addition to GPU support, which provides flexibility in use of resources and avoids memory limitations. Reference-free autopicking with Laplacian-of-Gaussian filtering and execution of jobs from python allows non-interactive processing during acquisition, including 2D-classification, de novo model generation and 3D-classification. Per-particle refinement of CTF parameters and correction of estimated beam tilt provides higher resolution reconstructions when particles are at different heights in the ice, and/or coma-free alignment has not been optimal. Ewald sphere curvature correction improves resolution for large particles. We illustrate these developments with publicly available data sets: together with a Bayesian approach to beam-induced motion correction it leads to resolution improvements of 0.2–0.7 Å compared to previous RELION versions.
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Affiliation(s)
- Jasenko Zivanov
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Takanori Nakane
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Björn O Forsberg
- Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, Stockholm, Sweden
| | - Dari Kimanius
- Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, Stockholm, Sweden
| | - Wim Jh Hagen
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany.,Cryo-Electron Microscopy Service Platform, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Erik Lindahl
- Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, Stockholm, Sweden.,Department of Applied Physics, Swedish e-Science Research Center, KTH Royal Institute of Technology, Stockholm, Sweden
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581
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Mendez JH, Stagg SM. Assessing the quality of single particle reconstructions by atomic model building. J Struct Biol 2018; 204:276-282. [PMID: 30213768 PMCID: PMC6201253 DOI: 10.1016/j.jsb.2018.09.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 09/05/2018] [Accepted: 09/08/2018] [Indexed: 10/28/2022]
Abstract
The 2015/2016 Map Challenge challenged cryo-EM practitioners to process a series of publicly available cryo-EM datasets. As part of the challenge, metrics needed to be developed to assess and compare the quality of the different map submissions. The most common metric for assessing maps is determining the resolution by Fourier shell correlation (FSC), but there are well known instances where the resolution can be misleading. In this manuscript, we present a new approach for assessing the quality of a map by determining the map "modelability" rather than on resolution. We used the automated map tracing and modeling algorithms in Rosetta to generate populations of models, and then compared the populations between different map entries by the Rosetta score, RMSD to a reference model provided by the map challenge, and by pair-wise RMSDs between different models in the population. These metrics were used to determine statistically significant rankings for the map challengers for each dataset. The rankings revealed inconsistencies between the resolution by FSC, emphasized the importance of the interplay between number of particles contributing to a map and map quality, and revealed the importance of software familiarity on single particle reconstruction results. However, because multiple variables changed between map entries, it was challenging to derive best practices from the map challenge results.
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Affiliation(s)
- Joshua H Mendez
- Department of Physics, 77 Chieftan Way, Tallahassee, FL 32306, United States
| | - Scott M Stagg
- Institute of Molecular Biophysics, 91 Chieftain Way, Florida State University, Tallahassee, FL 32306, United States; Department of Chemistry and Biochemistry, 95 Chieftain Way, Florida State University, Tallahassee, FL 32306, United States.
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582
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Himes BA, Zhang P. emClarity: software for high-resolution cryo-electron tomography and subtomogram averaging. Nat Methods 2018; 15:955-961. [PMID: 30349041 PMCID: PMC6281437 DOI: 10.1038/s41592-018-0167-z] [Citation(s) in RCA: 166] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2017] [Accepted: 07/25/2018] [Indexed: 11/17/2022]
Abstract
Macromolecular complexes are intrinsically flexible and often challenging to purify for structure determination by single particle cryoEM. Such complexes may be studied using cryo-electron tomography combined with sub-tomogram alignment and classification, which in exceptional cases reaches sub-nanometer resolution, yielding insight into structure-function relationships. Extending this approach to specimens that exhibit conformational or compositional heterogeneity, and that may be present at low abundance, remains challenging. To address this challenge, we developed emClarity (https://github.com/bHimes/emClarity/wiki), a GPU-accelerated image processing package, which features an iterative tomographic tilt-series refinement algorithm using sub-tomograms as fiducial markers and a 3D-samping function compensated, multi-scale Principle Component Analysis classification method. We demonstrate substantial improvements in the resolution of maps and in the separation of different functional states of macromolecular complexes, compared to those generated using current state-of-the-art software.
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Affiliation(s)
- Benjamin A Himes
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.,Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Peijun Zhang
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA. .,Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK. .,Electron Bio-Imaging Centre, Diamond Light Source, Didcot, UK.
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583
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Fay JF, Aleksandrov LA, Jensen TJ, Cui LL, Kousouros JN, He L, Aleksandrov AA, Gingerich DS, Riordan JR, Chen JZ. Cryo-EM Visualization of an Active High Open Probability CFTR Anion Channel. Biochemistry 2018; 57:6234-6246. [PMID: 30281975 DOI: 10.1021/acs.biochem.8b00763] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The cystic fibrosis transmembrane conductance regulator (CFTR) anion channel, crucial to epithelial salt and water homeostasis, and defective due to mutations in its gene in patients with cystic fibrosis, is a unique member of the large family of ATP-binding cassette transport proteins. Regulation of CFTR channel activity is stringently controlled by phosphorylation and nucleotide binding. Structural changes that underlie transitions between active and inactive functional states are not yet fully understood. Indeed the first 3D structures of dephosphorylated, ATP-free, and phosphorylated ATP-bound states were only recently reported. Here we have determined the structure of inactive and active states of a thermally stabilized CFTR, the latter with a very high channel open probability, confirmed after reconstitution into proteoliposomes. These structures, obtained at nominal resolution of 4.3 and 6.6 Å, reveal a unique repositioning of the transmembrane helices and regulatory domain density that provide insights into the structural transition between active and inactive functional states of CFTR. Moreover, we observe an extracellular vestibule that may provide anion access to the pore due to the conformation of transmembrane helices 7 and 8 that differs from the previous orthologue CFTR structures. In conclusion, our work contributes detailed structural information on an active, open state of the CFTR anion channel.
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Affiliation(s)
- Jonathan F Fay
- University of North Carolina , Chapel Hill , North Carolina 27515 , United States
| | - Luba A Aleksandrov
- University of North Carolina , Chapel Hill , North Carolina 27515 , United States
| | - Timothy J Jensen
- University of North Carolina , Chapel Hill , North Carolina 27515 , United States
| | - Liying L Cui
- University of North Carolina , Chapel Hill , North Carolina 27515 , United States
| | - Joseph N Kousouros
- University of North Carolina , Chapel Hill , North Carolina 27515 , United States
| | - Lihua He
- University of North Carolina , Chapel Hill , North Carolina 27515 , United States
| | - Andrei A Aleksandrov
- University of North Carolina , Chapel Hill , North Carolina 27515 , United States
| | - Drew S Gingerich
- Oregon Health & Science University , Portland , Oregon 97239 , United States
| | - John R Riordan
- University of North Carolina , Chapel Hill , North Carolina 27515 , United States
| | - James Z Chen
- Oregon Health & Science University , Portland , Oregon 97239 , United States
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584
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Flygaard RK, Boegholm N, Yusupov M, Jenner LB. Cryo-EM structure of the hibernating Thermus thermophilus 100S ribosome reveals a protein-mediated dimerization mechanism. Nat Commun 2018; 9:4179. [PMID: 30301898 PMCID: PMC6177447 DOI: 10.1038/s41467-018-06724-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 09/19/2018] [Indexed: 12/03/2022] Open
Abstract
In response to cellular stresses bacteria conserve energy by dimerization of ribosomes into inactive hibernating 100S ribosome particles. Ribosome dimerization in Thermus thermophilus is facilitated by hibernation-promoting factor (TtHPF). In this study we demonstrate high sensitivity of Tt100S formation to the levels of TtHPF and show that a 1:1 ratio leads to optimal dimerization. We report structures of the T. thermophilus 100S ribosome determined by cryo-electron microscopy to average resolutions of 4.13 Å and 4.57 Å. In addition, we present a 3.28 Å high-resolution cryo-EM reconstruction of a 70S ribosome from a hibernating ribosome dimer and reveal a role for the linker region connecting the TtHPF N- and C-terminal domains in translation inhibition by preventing Shine-Dalgarno duplex formation. Our work demonstrates that species-specific differences in the dimerization interface govern the overall conformation of the 100S ribosome particle and that for Thermus thermophilus no ribosome-ribosome interactions are involved in the interface.
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Affiliation(s)
- Rasmus Kock Flygaard
- Department of Molecular Biology and Genetics, Aarhus University, 8000, Aarhus C, Denmark
| | - Niels Boegholm
- Department of Molecular Biology and Genetics, Aarhus University, 8000, Aarhus C, Denmark
| | - Marat Yusupov
- Department of Integrated Structural Biology, Institute of Genetics and Molecular and Cellular Biology, CNRS UMR710, INSERM U964, University of Strasbourg, Strasbourg, 67000, France
- Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, 420008, Russia
| | - Lasse B Jenner
- Department of Integrated Structural Biology, Institute of Genetics and Molecular and Cellular Biology, CNRS UMR710, INSERM U964, University of Strasbourg, Strasbourg, 67000, France.
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585
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Noble AJ, Wei H, Dandey VP, Zhang Z, Tan YZ, Potter CS, Carragher B. Reducing effects of particle adsorption to the air-water interface in cryo-EM. Nat Methods 2018; 15:793-795. [PMID: 30250056 PMCID: PMC6168394 DOI: 10.1038/s41592-018-0139-3] [Citation(s) in RCA: 136] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 07/25/2018] [Indexed: 12/31/2022]
Abstract
Most protein particles prepared in vitreous ice for single-particle cryo-electron microscopy (cryo-EM) are adsorbed to air-water or substrate-water interfaces, which can cause the particles to adopt preferred orientations. By using a rapid plunge-freezing robot and nanowire grids, we were able to reduce some of the deleterious effects of the air-water interface by decreasing the dwell time of particles in thin liquid films. We demonstrated this by using single-particle cryo-EM and cryo-electron tomography (cryo-ET) to examine hemagglutinin, insulin receptor complex, and apoferritin.
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Affiliation(s)
- Alex J Noble
- National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, USA
| | - Hui Wei
- National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, USA
| | - Venkata P Dandey
- National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, USA
| | - Zhening Zhang
- National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, USA
| | - Yong Zi Tan
- National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, USA
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Clinton S Potter
- National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, USA
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Bridget Carragher
- National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, USA.
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA.
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586
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Noreng S, Bharadwaj A, Posert R, Yoshioka C, Baconguis I. Structure of the human epithelial sodium channel by cryo-electron microscopy. eLife 2018; 7:39340. [PMID: 30251954 PMCID: PMC6197857 DOI: 10.7554/elife.39340] [Citation(s) in RCA: 117] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 09/18/2018] [Indexed: 12/11/2022] Open
Abstract
The epithelial sodium channel (ENaC), a member of the ENaC/DEG superfamily, regulates Na+ and water homeostasis. ENaCs assemble as heterotrimeric channels that harbor protease-sensitive domains critical for gating the channel. Here, we present the structure of human ENaC in the uncleaved state determined by single-particle cryo-electron microscopy. The ion channel is composed of a large extracellular domain and a narrow transmembrane domain. The structure reveals that ENaC assembles with a 1:1:1 stoichiometry of α:β:γ subunits arranged in a counter-clockwise manner. The shape of each subunit is reminiscent of a hand with key gating domains of a 'finger' and a 'thumb.' Wedged between these domains is the elusive protease-sensitive inhibitory domain poised to regulate conformational changes of the 'finger' and 'thumb'; thus, the structure provides the first view of the architecture of inhibition of ENaC.
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Affiliation(s)
- Sigrid Noreng
- Department of Biochemistry & Molecular Biology, Oregon Health and Science University, Portland, United States
| | - Arpita Bharadwaj
- Vollum Institute, Oregon Health and Science University, Portland, United States
| | - Richard Posert
- Department of Biochemistry & Molecular Biology, Oregon Health and Science University, Portland, United States
| | - Craig Yoshioka
- Department of Biomedical Engineering, Oregon Health and Science University, Portland, United States
| | - Isabelle Baconguis
- Vollum Institute, Oregon Health and Science University, Portland, United States
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587
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Huang Y, Winkler PA, Sun W, Lü W, Du J. Architecture of the TRPM2 channel and its activation mechanism by ADP-ribose and calcium. Nature 2018; 562:145-149. [PMID: 30250252 DOI: 10.1038/s41586-018-0558-4] [Citation(s) in RCA: 125] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 08/03/2018] [Indexed: 12/16/2022]
Abstract
Transient receptor potential melastatin 2 (TRPM2) is a calcium-permeable, non-selective cation channel that has an essential role in diverse physiological processes such as core body temperature regulation, immune response and apoptosis1-4. TRPM2 is polymodal and can be activated by a wide range of stimuli1-7, including temperature, oxidative stress and NAD+-related metabolites such as ADP-ribose (ADPR). Its activation results in both Ca2+ entry across the plasma membrane and Ca2+ release from lysosomes8, and has been linked to diseases such as ischaemia-reperfusion injury, bipolar disorder and Alzheimer's disease9-11. Here we report the cryo-electron microscopy structures of the zebrafish TRPM2 in the apo resting (closed) state and in the ADPR/Ca2+-bound active (open) state, in which the characteristic NUDT9-H domains hang underneath the MHR1/2 domain. We identify an ADPR-binding site located in the bi-lobed structure of the MHR1/2 domain. Our results provide an insight into the mechanism of activation of the TRPM channel family and define a framework for the development of therapeutic agents to treat neurodegenerative diseases and temperature-related pathological conditions.
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Affiliation(s)
- Yihe Huang
- Van Andel Research Institute, Grand Rapids, MI, USA
| | | | - Weinan Sun
- Vollum Institute, Oregon Health & Science University, Portland, OR, USA.,Janelia Research Campus, Ashburn, VA, USA
| | - Wei Lü
- Van Andel Research Institute, Grand Rapids, MI, USA.
| | - Juan Du
- Van Andel Research Institute, Grand Rapids, MI, USA.
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588
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Zhang C, Konermann S, Brideau NJ, Lotfy P, Wu X, Novick SJ, Strutzenberg T, Griffin PR, Hsu PD, Lyumkis D. Structural Basis for the RNA-Guided Ribonuclease Activity of CRISPR-Cas13d. Cell 2018; 175:212-223.e17. [PMID: 30241607 PMCID: PMC6179368 DOI: 10.1016/j.cell.2018.09.001] [Citation(s) in RCA: 163] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 08/01/2018] [Accepted: 09/04/2018] [Indexed: 12/11/2022]
Abstract
CRISPR-Cas endonucleases directed against foreign nucleic acids mediate prokaryotic adaptive immunity and have been tailored for broad genetic engineering applications. Type VI-D CRISPR systems contain the smallest known family of single effector Cas enzymes, and their signature Cas13d ribonuclease employs guide RNAs to cleave matching target RNAs. To understand the molecular basis for Cas13d function and explain its compact molecular architecture, we resolved cryoelectron microscopy structures of Cas13d-guide RNA binary complex and Cas13d-guide-target RNA ternary complex to 3.4 and 3.3 Å resolution, respectively. Furthermore, a 6.5 Å reconstruction of apo Cas13d combined with hydrogen-deuterium exchange revealed conformational dynamics that have implications for RNA scanning. These structures, together with biochemical and cellular characterization, provide insights into its RNA-guided, RNA-targeting mechanism and delineate a blueprint for the rational design of improved transcriptome engineering technologies.
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Affiliation(s)
- Cheng Zhang
- Laboratory of Genetics, Salk Institute for Biological Studies, 10010 N. Torrey Pines Road, La Jolla, CA 92037, USA; Helmsley Center for Genomic Medicine, Salk Institute for Biological Studies, 10010 N. Torrey Pines Road, La Jolla, CA 92037, USA
| | - Silvana Konermann
- Laboratory of Molecular and Cell Biology, Salk Institute for Biological Studies, 10010 N. Torrey Pines Road, La Jolla, CA 92037, USA; Helmsley Center for Genomic Medicine, Salk Institute for Biological Studies, 10010 N. Torrey Pines Road, La Jolla, CA 92037, USA
| | - Nicholas J Brideau
- Laboratory of Molecular and Cell Biology, Salk Institute for Biological Studies, 10010 N. Torrey Pines Road, La Jolla, CA 92037, USA; Helmsley Center for Genomic Medicine, Salk Institute for Biological Studies, 10010 N. Torrey Pines Road, La Jolla, CA 92037, USA
| | - Peter Lotfy
- Laboratory of Molecular and Cell Biology, Salk Institute for Biological Studies, 10010 N. Torrey Pines Road, La Jolla, CA 92037, USA; Helmsley Center for Genomic Medicine, Salk Institute for Biological Studies, 10010 N. Torrey Pines Road, La Jolla, CA 92037, USA
| | - Xuebing Wu
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | - Scott J Novick
- Department of Molecular Medicine, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Timothy Strutzenberg
- Department of Molecular Medicine, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Patrick R Griffin
- Department of Molecular Medicine, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Patrick D Hsu
- Laboratory of Molecular and Cell Biology, Salk Institute for Biological Studies, 10010 N. Torrey Pines Road, La Jolla, CA 92037, USA; Helmsley Center for Genomic Medicine, Salk Institute for Biological Studies, 10010 N. Torrey Pines Road, La Jolla, CA 92037, USA.
| | - Dmitry Lyumkis
- Laboratory of Genetics, Salk Institute for Biological Studies, 10010 N. Torrey Pines Road, La Jolla, CA 92037, USA; Helmsley Center for Genomic Medicine, Salk Institute for Biological Studies, 10010 N. Torrey Pines Road, La Jolla, CA 92037, USA.
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589
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Membrane protein structural biology in the era of single particle cryo-EM. Curr Opin Struct Biol 2018; 52:58-63. [PMID: 30219656 DOI: 10.1016/j.sbi.2018.08.008] [Citation(s) in RCA: 100] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Revised: 05/15/2018] [Accepted: 08/29/2018] [Indexed: 11/22/2022]
Abstract
In the past few years, significant technological breakthroughs in single particle cryo-electron microscopy enabled a 'resolution revolution' of this technique. It also changed structural biology in an unprecedented way. For many biological macromolecules, obtaining well-ordered crystals of suitable size is no longer a prerequisite for determining their atomic structures. One of the most impacted areas is the structural biology of integral membrane proteins. New structures are now determined at a rapid pace. Despite these advances, further technological developments are still required to overcome new technical challenges that face membrane protein structural biology. In this review, I attempt to discuss some of these challenges.
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590
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Carvalho V, Pronk JW, Engel AH. Characterization of Membrane Proteins Using Cryo-Electron Microscopy. ACTA ACUST UNITED AC 2018; 94:e72. [PMID: 30199146 DOI: 10.1002/cpps.72] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The steep increase of atomic scale structures determined by 3D cryo-electron microscopy (EM) deposited in the EMDataBank documents progress of a methodology that was frustratingly slow ten years ago. While sample vitrification on grids has been successfully used in all EM laboratories for decades, beam damage remains a road block. Developments in instrumentation and software to exploit the information carried by elastically scattered electrons made the task to achieve atomic scale resolution easier. This together with the development of fast single electron detecting cameras has resulted in unprecedented possibilities for structure determination by 3D cryo-EM. With such technologies in place, the purification of membrane protein complexes in a functional state is key to collecting atomic scale structural information and insight into the chemistry of physiological processes. Therefore, we focus here on the preparation of membrane proteins for structural analyses by 3D cryo-EM and the data acquisition of such vitrified samples. © 2018 by John Wiley & Sons, Inc.
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Affiliation(s)
- Vanessa Carvalho
- Department of Bionanoscience, Applied Sciences, Delft University of Technology, Delft, The Netherlands
| | - Joachim W Pronk
- Department of Bionanoscience, Applied Sciences, Delft University of Technology, Delft, The Netherlands
| | - Andreas H Engel
- Department of Bionanoscience, Applied Sciences, Delft University of Technology, Delft, The Netherlands
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591
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Sub-2 Å Ewald curvature corrected structure of an AAV2 capsid variant. Nat Commun 2018; 9:3628. [PMID: 30194371 PMCID: PMC6128836 DOI: 10.1038/s41467-018-06076-6] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 08/11/2018] [Indexed: 01/08/2023] Open
Abstract
Single-particle cryogenic electron microscopy (cryo-EM) provides a powerful methodology for structural biologists, but the resolutions typically attained with experimentally determined structures have lagged behind microscope capabilities. Here, we exploit several technical advances to improve resolution, including per-particle contrast transfer function (CTF) refinement and correction for Ewald sphere curvature. The latter is demonstrated with several experimental samples and should become more standard as resolutions increase or at lower microscope accelerating voltages. The combined application of the described methods to micrographs recorded on a Titan Krios enables structure determination at ~1.86-Å resolution of an adeno-associated virus serotype 2 variant (AAV2), an important gene-delivery vehicle. The resulting structural details provide an improved model for understanding the biology of AAV that will guide future vector development for gene therapy. Single-particle cryo-EM is a powerful method for macromolecular structure determination. Here the authors demonstrate that Ewald sphere curvature correction, sub-Angstrom pixilation and per-particle CTF refinement can improve map quality and resolution and present the 1.86 Å cryo-EM structure of an adeno-associated virus serotype 2 variant.
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592
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Qu Q, Takahashi YH, Yang Y, Hu H, Zhang Y, Brunzelle JS, Couture JF, Shilatifard A, Skiniotis G. Structure and Conformational Dynamics of a COMPASS Histone H3K4 Methyltransferase Complex. Cell 2018; 174:1117-1126.e12. [PMID: 30100186 PMCID: PMC6108936 DOI: 10.1016/j.cell.2018.07.020] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 06/25/2018] [Accepted: 07/16/2018] [Indexed: 11/25/2022]
Abstract
The methylation of histone 3 lysine 4 (H3K4) is carried out by an evolutionarily conserved family of methyltransferases referred to as complex of proteins associated with Set1 (COMPASS). The activity of the catalytic SET domain (su(var)3-9, enhancer-of-zeste, and trithorax) is endowed through forming a complex with a set of core proteins that are widely shared from yeast to humans. We obtained cryo-electron microscopy (cryo-EM) maps of the yeast Set1/COMPASS core complex at overall 4.0- to 4.4-Å resolution, providing insights into its structural organization and conformational dynamics. The Cps50 C-terminal tail weaves within the complex to provide a central scaffold for assembly. The SET domain, snugly positioned at the junction of the Y-shaped complex, is extensively contacted by Cps60 (Bre2), Cps50 (Swd1), and Cps30 (Swd3). The mobile SET-I motif of the SET domain is engaged by Cps30, explaining its key role in COMPASS catalytic activity toward higher H3K4 methylation states.
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Affiliation(s)
- Qianhui Qu
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Yoh-Hei Takahashi
- Department of Biochemistry and Molecular Genetics, Simpson Querrey Center for Epigenetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Yidai Yang
- Department of Biochemistry, Microbiology, and Immunology, Ottawa Institute of Systems Biology, University of Ottawa, Ottawa ON K1H 8M5, Canada
| | - Hongli Hu
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Yan Zhang
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Joseph S Brunzelle
- Northwestern Synchrotron Research Center, Life Sciences Collaborative Access Team, Northwestern University, Argonne, IL 60439, USA
| | - Jean-Francois Couture
- Department of Biochemistry, Microbiology, and Immunology, Ottawa Institute of Systems Biology, University of Ottawa, Ottawa ON K1H 8M5, Canada
| | - Ali Shilatifard
- Department of Biochemistry and Molecular Genetics, Simpson Querrey Center for Epigenetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
| | - Georgios Skiniotis
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA.
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593
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Scapin G, Potter CS, Carragher B. Cryo-EM for Small Molecules Discovery, Design, Understanding, and Application. Cell Chem Biol 2018; 25:1318-1325. [PMID: 30100349 DOI: 10.1016/j.chembiol.2018.07.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 05/11/2018] [Accepted: 07/05/2018] [Indexed: 12/13/2022]
Abstract
We present a perspective of our view of the application of cryoelectron microscopy (cryo-EM) to structure-based drug design (SBDD). We discuss the basic needs and requirements for SBDD, the current state of cryo-EM, and the challenges that need to be overcome for this technique to reach its full potential in facilitating the process of drug discovery.
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Affiliation(s)
- Giovanna Scapin
- Department of Biochemical Engineering & Structure, Merck & Co., Inc., 2000 Galloping Hill Rd., Kenilworth, NJ 07033, USA
| | - Clinton S Potter
- Simons Electron Microscopy Center, National Resource for Automated Molecular Microscopy, New York Structural Biology Center, 89 Convent Avenue, New York NY 10027, USA; NanoImaging Services, 4940 Carroll Canyon Road, Suite 115, San Diego, CA 92121, USA
| | - Bridget Carragher
- Simons Electron Microscopy Center, National Resource for Automated Molecular Microscopy, New York Structural Biology Center, 89 Convent Avenue, New York NY 10027, USA; NanoImaging Services, 4940 Carroll Canyon Road, Suite 115, San Diego, CA 92121, USA.
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594
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Ge J, Elferich J, Goehring A, Zhao H, Schuck P, Gouaux E. Structure of mouse protocadherin 15 of the stereocilia tip link in complex with LHFPL5. eLife 2018; 7:38770. [PMID: 30070639 PMCID: PMC6092121 DOI: 10.7554/elife.38770] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 07/31/2018] [Indexed: 11/13/2022] Open
Abstract
Hearing and balance involve the transduction of mechanical stimuli into electrical signals by deflection of bundles of stereocilia linked together by protocadherin 15 (PCDH15) and cadherin 23 'tip links'. PCDH15 transduces tip link tension into opening of a mechano-electrical transduction (MET) ion channel. PCDH15 also interacts with LHFPL5, a candidate subunit of the MET channel. Here we illuminate the PCDH15-LHFPL5 structure, showing how the complex is composed of PCDH15 and LHFPL5 subunit pairs related by a 2-fold axis. The extracellular cadherin domains define a mobile tether coupled to a rigid, 2-fold symmetric 'collar' proximal to the membrane bilayer. LHFPL5 forms extensive interactions with the PCDH15 transmembrane helices and stabilizes the overall PCDH15-LHFPL5 assembly. Our studies illuminate the architecture of the PCDH15-LHFPL5 complex, localize mutations associated with deafness, and shed new light on how forces in the PCDH15 tether may be transduced into the stereocilia membrane.
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Affiliation(s)
- Jingpeng Ge
- Vollum Institute, Oregon Health & Science University, Portland, United States
| | - Johannes Elferich
- Vollum Institute, Oregon Health & Science University, Portland, United States
| | - April Goehring
- Vollum Institute, Oregon Health & Science University, Portland, United States
| | - Huaying Zhao
- Laboratory of Cellular Imaging and Macromolecular Biophysics, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, United States
| | - Peter Schuck
- Laboratory of Cellular Imaging and Macromolecular Biophysics, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, United States
| | - Eric Gouaux
- Vollum Institute, Oregon Health & Science University, Portland, United States.,Howard Hughes Medical Institute, Oregon Health & Science University, Portland, United States
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595
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Paknejad N, Hite RK. Structural basis for the regulation of inositol trisphosphate receptors by Ca 2+ and IP 3. Nat Struct Mol Biol 2018; 25:660-668. [PMID: 30013099 PMCID: PMC6082148 DOI: 10.1038/s41594-018-0089-6] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 06/18/2018] [Indexed: 11/17/2022]
Abstract
Inositol trisphosphate receptors (IP3R) are ubiquitous Ca2+-permeable channels that mediate release of Ca2+ from the endoplasmic reticulum to regulate numerous processes including cell division, cell death, differentiation and fertilization. IP3R is activated by both IP3 and its permeant ion Ca2+. At high concentrations, however, Ca2+ inhibits activity ensuring precise spatiotemporal control over intracellular Ca2+. Despite extensive characterization of IP3R, the mechanisms by which these molecules control channel gating have remained elusive. Here, we present structures of full-length human type 3 IP3R in ligand-bound and ligand-free states. Multiple IP3-bound structures demonstrate that the large cytoplasmic domain provides a platform for propagation of long-range conformational changes to the ion conduction gate. Structures in the presence of Ca2+ reveal two Ca2+ binding sites that induce the disruption of numerous interactions between subunits, thereby inhibiting IP3R. These structures thus begin to provide a mechanistic basis for understanding the regulation of IP3R.
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Affiliation(s)
- Navid Paknejad
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA.,Physiology, Biophysics and Systems Biology Graduate Program, Weill Cornell Medical College, New York, NY, USA
| | - Richard K Hite
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
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596
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Cryo-EM structures of fungal and metazoan mitochondrial calcium uniporters. Nature 2018; 559:580-584. [PMID: 29995857 DOI: 10.1038/s41586-018-0331-8] [Citation(s) in RCA: 108] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Accepted: 06/19/2018] [Indexed: 12/22/2022]
Abstract
The mitochondrial calcium uniporter (MCU) is a highly selective calcium channel and a major route of calcium entry into mitochondria. How the channel catalyses ion permeation and achieves ion selectivity are not well understood, partly because MCU is thought to have a distinct architecture in comparison to other cellular channels. Here we report cryo-electron microscopy reconstructions of MCU channels from zebrafish and Cyphellophora europaea at 8.5 Å and 3.2 Å resolutions, respectively. In contrast to a previous report of pentameric stoichiometry for MCU, both channels are tetramers. The atomic model of C. europaea MCU shows that a conserved WDXXEP signature sequence forms the selectivity filter, in which calcium ions are arranged in single file. Coiled-coil legs connect the pore to N-terminal domains in the mitochondrial matrix. In C. europaea MCU, the N-terminal domains assemble as a dimer of dimers; in zebrafish MCU, they form an asymmetric crescent. The structures define principles that underlie ion permeation and calcium selectivity in this unusual channel.
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597
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Stagg SM, Mendez JH. Processing apoferritin with the Appion pipeline. J Struct Biol 2018; 204:85-89. [PMID: 29969662 DOI: 10.1016/j.jsb.2018.06.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 06/08/2018] [Accepted: 06/29/2018] [Indexed: 01/26/2023]
Abstract
The 3DEM map challenge provided an opportunity to test different algorithms and workflows for processing single particle cryo-EM data. We were interested in testing whether we could use the standard Appion workflow with minimal manual intervention to achieve similar or better resolution than other challengers. Another question we were interested in testing was what the influence of particle sorting and elimination would be on the resolution and quality of 3D reconstructions. Since apoferritin is historically a challenging particle for single particle reconstruction and the authors of the original map challenge data used only a fraction of the particles present in the dataset, we focused on the apoferritin dataset for our entry. We submitted a 3.7 Å map from 25,844 particles and a 3.6 Å map from 53,334 particles and after assessment were among the best of the apoferritin maps that were submitted. Here we present the details of our reconstruction strategy and compare our strategy to that of another high-scoring apoferritin map. Altogether, our results suggest that for a relatively conformationally homogeneous particle like apoferritin, including as many particles as possible after elimination of junk leads to the highest resolution, and the choice of parameters for custom mask creation can lead to subtle but significant changes in the resolution of 3D reconstructions.
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Affiliation(s)
- Scott M Stagg
- Institute of Molecular Biophysics, 91 Chieftain Way, Florida State University, Tallahassee, FL 32306, United States; Department of Chemistry and Biochemistry, 95 Chieftain Way, Florida State University, Tallahassee, FL 32306, United States.
| | - Joshua H Mendez
- Department of Physics, 77 Chieftan Way, Tallahassee, FL 32306, United States
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598
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Svidritskiy E, Demo G, Korostelev AA. Mechanism of premature translation termination on a sense codon. J Biol Chem 2018; 293:12472-12479. [PMID: 29941456 DOI: 10.1074/jbc.aw118.003232] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Accurate translation termination by release factors (RFs) is critical for the integrity of cellular proteomes. Premature termination on sense codons, for example, results in truncated proteins, whose accumulation could be detrimental to the cell. Nevertheless, some sense codons are prone to triggering premature termination, but the structural basis for this is unclear. To investigate premature termination, we determined a cryo-EM structure of the Escherichia coli 70S ribosome bound with RF1 in response to a UAU (Tyr) sense codon. The structure reveals that RF1 recognizes a UAU codon similarly to a UAG stop codon, suggesting that sense codons induce premature termination because they structurally mimic a stop codon. Hydrophobic interaction between the nucleobase of U3 (the third position of the UAU codon) and conserved Ile-196 in RF1 is important for misreading the UAU codon. Analyses of RNA binding in ribonucleoprotein complexes or by amino acids reveal that Ile-U packing is a frequent protein-RNA-binding motif with key functional implications. We discuss parallels with eukaryotic translation termination by the release factor eRF1.
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Affiliation(s)
- Egor Svidritskiy
- From the RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | - Gabriel Demo
- From the RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | - Andrei A Korostelev
- From the RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, Massachusetts 01605
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599
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600
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Nakane T, Kimanius D, Lindahl E, Scheres SH. Characterisation of molecular motions in cryo-EM single-particle data by multi-body refinement in RELION. eLife 2018; 7:36861. [PMID: 29856314 PMCID: PMC6005684 DOI: 10.7554/elife.36861] [Citation(s) in RCA: 318] [Impact Index Per Article: 53.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 05/31/2018] [Indexed: 12/18/2022] Open
Abstract
Macromolecular complexes that exhibit continuous forms of structural flexibility pose a challenge for many existing tools in cryo-EM single-particle analysis. We describe a new tool, called multi-body refinement, which models flexible complexes as a user-defined number of rigid bodies that move independently from each other. Using separate focused refinements with iteratively improved partial signal subtraction, the new tool generates improved reconstructions for each of the defined bodies in a fully automated manner. Moreover, using principal component analysis on the relative orientations of the bodies over all particle images in the data set, we generate movies that describe the most important motions in the data. Our results on two test cases, a cytoplasmic ribosome from Plasmodium falciparum, and the spliceosomal B-complex from yeast, illustrate how multi-body refinement can be useful to gain unique insights into the structure and dynamics of large and flexible macromolecular complexes.
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Affiliation(s)
- Takanori Nakane
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Dari Kimanius
- Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, Stockholm, Sweden
| | - Erik Lindahl
- Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, Stockholm, Sweden.,Swedish e-Science Research Center, KTH Royal Institute of Technology, Stockholm, Sweden
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