1
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Yeo J, Daurer BJ, Kimanius D, Balakrishnan D, Bepler T, Tan YZ, Loh ND. Ghostbuster: A phase retrieval diffraction tomography algorithm for cryo-EM. Ultramicroscopy 2024; 262:113962. [PMID: 38642481 DOI: 10.1016/j.ultramic.2024.113962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 03/16/2024] [Accepted: 04/01/2024] [Indexed: 04/22/2024]
Abstract
Ewald sphere curvature correction, which extends beyond the projection approximation, stretches the shallow depth of field in cryo-EM reconstructions of thick particles. Here we show that even for previously assumed thin particles, reconstruction artifacts which we refer to as ghosts can appear. By retrieving the lost phases of the electron exitwaves and accounting for the first Born approximation scattering within the particle, we show that these ghosts can be effectively eliminated. Our simulations demonstrate how such ghostbusting can improve reconstructions as compared to existing state-of-the-art software. Like ptychographic cryo-EM, our Ghostbuster algorithm uses phase retrieval to improve reconstructions, but unlike the former, we do not need to modify the existing data acquisition pipelines.
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Affiliation(s)
- Joel Yeo
- NUS Graduate School for Integrative Sciences and Engineering Programme, National University of Singapore, 119077 Singapore, Singapore; Department of Physics, National University of Singapore, 117551 Singapore, Singapore; Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, 138634 Singapore, Singapore
| | - Benedikt J Daurer
- Center for Bio-Imaging Sciences, National University of Singapore, 117557 Singapore, Singapore; Diamond Light Source, Harwell Campus, Didcot, OX11 0DE, UK
| | - Dari Kimanius
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK; CZ Imaging Institute, 3400 Bridge Parkway, Redwood City, CA 94065, USA
| | - Deepan Balakrishnan
- Department of Biological Sciences, National University of Singapore, 117558 Singapore, Singapore; Center for Bio-Imaging Sciences, National University of Singapore, 117557 Singapore, Singapore
| | - Tristan Bepler
- Simons Machine Learning Center, New York Structural Biology Center, New York, NY, USA
| | - Yong Zi Tan
- Department of Biological Sciences, National University of Singapore, 117558 Singapore, Singapore; Center for Bio-Imaging Sciences, National University of Singapore, 117557 Singapore, Singapore; Disease Intervention Technology Laboratory (DITL), Agency for Science, Technology and Research (A*STAR), 8A Biomedical Grove, 138648 Singapore, Singapore; Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), 61 Biopolis Drive, Proteos, 138673 Singapore, Singapore
| | - N Duane Loh
- NUS Graduate School for Integrative Sciences and Engineering Programme, National University of Singapore, 119077 Singapore, Singapore; Department of Physics, National University of Singapore, 117551 Singapore, Singapore; Department of Biological Sciences, National University of Singapore, 117558 Singapore, Singapore; Center for Bio-Imaging Sciences, National University of Singapore, 117557 Singapore, Singapore.
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2
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Gemmer M, Chaillet ML, Förster F. Exploring the molecular composition of the multipass translocon in its native membrane environment. Life Sci Alliance 2024; 7:e202302496. [PMID: 38866426 PMCID: PMC11169918 DOI: 10.26508/lsa.202302496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 05/22/2024] [Accepted: 05/23/2024] [Indexed: 06/14/2024] Open
Abstract
Multispanning membrane proteins are inserted into the endoplasmic reticulum membrane by the ribosome-bound multipass translocon (MPT) machinery. Based on cryo-electron tomography and extensive subtomogram analysis, we reveal the composition and arrangement of ribosome-bound MPT components in their native membrane environment. The intramembrane chaperone complex PAT and the translocon-associated protein (TRAP) complex associate substoichiometrically with the MPT in a translation-dependent manner. Although PAT is preferentially part of MPTs bound to translating ribosomes, the abundance of TRAP is highest in MPTs associated with non-translating ribosomes. The subtomogram average of the TRAP-containing MPT reveals intermolecular contacts between the luminal domains of TRAP and an unknown subunit of the back-of-Sec61 complex. AlphaFold modeling suggests this protein is nodal modulator, bridging the luminal domains of nicalin and TRAPα. Collectively, our results visualize the variability of MPT factors in the native membrane environment dependent on the translational activity of the bound ribosome.
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Affiliation(s)
- Max Gemmer
- https://ror.org/04pp8hn57 Structural Biochemistry, Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, Netherlands
| | - Marten L Chaillet
- https://ror.org/04pp8hn57 Structural Biochemistry, Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, Netherlands
| | - Friedrich Förster
- https://ror.org/04pp8hn57 Structural Biochemistry, Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, Netherlands
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3
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Held RG, Liang J, Brunger AT. Nanoscale architecture of synaptic vesicles and scaffolding complexes revealed by cryo-electron tomography. Proc Natl Acad Sci U S A 2024; 121:e2403136121. [PMID: 38923992 DOI: 10.1073/pnas.2403136121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2024] [Accepted: 05/16/2024] [Indexed: 06/28/2024] Open
Abstract
The spatial distribution of proteins and their arrangement within the cellular ultrastructure regulates the opening of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors in response to glutamate release at the synapse. Fluorescence microscopy imaging revealed that the postsynaptic density (PSD) and scaffolding proteins in the presynaptic active zone (AZ) align across the synapse to form a trans-synaptic "nanocolumn," but the relation to synaptic vesicle release sites is uncertain. Here, we employ focused-ion beam (FIB) milling and cryoelectron tomography to image synapses under near-native conditions. Improved image contrast, enabled by FIB milling, allows simultaneous visualization of supramolecular nanoclusters within the AZ and PSD and synaptic vesicles. Surprisingly, membrane-proximal synaptic vesicles, which fuse to release glutamate, are not preferentially aligned with AZ or PSD nanoclusters. These synaptic vesicles are linked to the membrane by peripheral protein densities, often consistent in size and shape with Munc13, as well as globular densities bridging the synaptic vesicle and plasma membrane, consistent with prefusion complexes of SNAREs, synaptotagmins, and complexin. Monte Carlo simulations of synaptic transmission events using biorealistic models guided by our tomograms predict that clustering AMPARs within PSD nanoclusters increases the variability of the postsynaptic response but not its average amplitude. Together, our data support a model in which synaptic strength is tuned at the level of single vesicles by the spatial relationship between scaffolding nanoclusters and single synaptic vesicle fusion sites.
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Affiliation(s)
- Richard G Held
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA 94305
- Department of Structural Biology, Stanford University, Stanford, CA 94305
- Department of Photon Science, Stanford University, Stanford, CA 94305
- HHMI, Stanford University, Stanford, CA 94305
| | - Jiahao Liang
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA 94305
- Department of Structural Biology, Stanford University, Stanford, CA 94305
- Department of Photon Science, Stanford University, Stanford, CA 94305
- HHMI, Stanford University, Stanford, CA 94305
| | - Axel T Brunger
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA 94305
- Department of Structural Biology, Stanford University, Stanford, CA 94305
- Department of Photon Science, Stanford University, Stanford, CA 94305
- HHMI, Stanford University, Stanford, CA 94305
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4
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Watson AJI, Bartesaghi A. Advances in cryo-ET data processing: meeting the demands of visual proteomics. Curr Opin Struct Biol 2024; 87:102861. [PMID: 38889501 DOI: 10.1016/j.sbi.2024.102861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Revised: 05/20/2024] [Accepted: 05/21/2024] [Indexed: 06/20/2024]
Abstract
Cryogenic electron tomography (cryo-ET), a method that enables the viewing of biomolecules in near-native environments at high resolution, is rising in accessibility and applicability. Over the past several years, once slow sample preparation and data collection procedures have seen innovations which enable rapid collection of the large datasets required for attaining high resolution structures. Increased data availability has provided a driving force for exciting improvements in cryo-ET data processing methodologies throughout the entire processing pipeline and the development of accessible graphical user interfaces (GUIs) that enable individuals inexperienced in computational fields to convert raw tilt series into 3D structures. These advances in data processing are enabling cryo-ET to attain higher resolution and extending its applicability to more complex samples.
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Affiliation(s)
- Abigail J I Watson
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Alberto Bartesaghi
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, 27710, USA; Department of Computer Science, Duke University, Durham, NC, 27708, USA; Department of Electrical and Computer Engineering, Duke University, Durham, NC, 27708, USA.
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5
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Kimanius D, Jamali K, Wilkinson ME, Lövestam S, Velazhahan V, Nakane T, Scheres SHW. Data-driven regularization lowers the size barrier of cryo-EM structure determination. Nat Methods 2024:10.1038/s41592-024-02304-8. [PMID: 38862790 DOI: 10.1038/s41592-024-02304-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 05/08/2024] [Indexed: 06/13/2024]
Abstract
Macromolecular structure determination by electron cryo-microscopy (cryo-EM) is limited by the alignment of noisy images of individual particles. Because smaller particles have weaker signals, alignment errors impose size limitations on its applicability. Here, we explore how image alignment is improved by the application of deep learning to exploit prior knowledge about biological macromolecular structures that would otherwise be difficult to express mathematically. We train a denoising convolutional neural network on pairs of half-set reconstructions from the electron microscopy data bank (EMDB) and use this denoiser as an alternative to a commonly used smoothness prior. We demonstrate that this approach, which we call Blush regularization, yields better reconstructions than do existing algorithms, in particular for data with low signal-to-noise ratios. The reconstruction of a protein-nucleic acid complex with a molecular weight of 40 kDa, which was previously intractable, illustrates that denoising neural networks will expand the applicability of cryo-EM structure determination for a wide range of biological macromolecules.
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Affiliation(s)
- Dari Kimanius
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, UK.
- CZ Imaging Institute, Redwood City, CA, USA.
| | - Kiarash Jamali
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, UK
| | - Max E Wilkinson
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, USA
- Howard Hughes Medical Institute, Cambridge, MA, USA
| | - Sofia Lövestam
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, UK
| | - Vaithish Velazhahan
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, UK
- School of Medicine, Stanford University, Stanford, CA, USA
| | - Takanori Nakane
- Institute for Protein Research, Osaka University, Suita-shi, Osaka, Japan
| | - Sjors H W Scheres
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, UK.
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6
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Khusainov I, Romanov N, Goemans C, Turoňová B, Zimmerli CE, Welsch S, Langer JD, Typas A, Beck M. Bactericidal effect of tetracycline in E. coli strain ED1a may be associated with ribosome dysfunction. Nat Commun 2024; 15:4783. [PMID: 38839776 PMCID: PMC11153495 DOI: 10.1038/s41467-024-49084-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2023] [Accepted: 05/23/2024] [Indexed: 06/07/2024] Open
Abstract
Ribosomes translate the genetic code into proteins. Recent technical advances have facilitated in situ structural analyses of ribosome functional states inside eukaryotic cells and the minimal bacterium Mycoplasma. However, such analyses of Gram-negative bacteria are lacking, despite their ribosomes being major antimicrobial drug targets. Here we compare two E. coli strains, a lab E. coli K-12 and human gut isolate E. coli ED1a, for which tetracycline exhibits bacteriostatic and bactericidal action, respectively. Using our approach for close-to-native E. coli sample preparation, we assess the two strains by cryo-ET and visualize their ribosomes at high resolution in situ. Upon tetracycline treatment, these exhibit virtually identical drug binding sites, yet the conformation distribution of ribosomal complexes differs. While K-12 retains ribosomes in a translation-competent state, tRNAs are lost in the vast majority of ED1a ribosomes. These structural findings together with the proteome-wide abundance and thermal stability assessments indicate that antibiotic responses are complex in cells and can differ between different strains of a single species, thus arguing that all relevant bacterial strains should be analyzed in situ when addressing antibiotic mode of action.
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Affiliation(s)
- Iskander Khusainov
- Department of Molecular Sociology, Max Planck Institute of Biophysics, Max-von-Laue-Straße 3, 60438, Frankfurt am Main, Germany
- European Molecular Biology Laboratory, EMBL Grenoble, 71 Av. des Martyrs, 38000, Grenoble, France
| | - Natalie Romanov
- Department of Molecular Sociology, Max Planck Institute of Biophysics, Max-von-Laue-Straße 3, 60438, Frankfurt am Main, Germany
| | - Camille Goemans
- European Molecular Biology Laboratory, Genome Biology Unit, Meyerhofstraße 1, 69117, Heidelberg, Germany
- School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), SV, Station 19, 1015, Lausanne, Switzerland
| | - Beata Turoňová
- Department of Molecular Sociology, Max Planck Institute of Biophysics, Max-von-Laue-Straße 3, 60438, Frankfurt am Main, Germany
| | - Christian E Zimmerli
- Department of Molecular Sociology, Max Planck Institute of Biophysics, Max-von-Laue-Straße 3, 60438, Frankfurt am Main, Germany
- Institute of Physics, École Polytechnique Fédérale de Lausanne (EPFL), BSP Route de la Sorge, 1015, Lausanne, Switzerland
| | - Sonja Welsch
- Central Electron Microscopy Facility, Max Planck Institute of Biophysics, Max-von-Laue-Straße 3, 60438, Frankfurt am Main, Germany
| | - Julian D Langer
- Membrane Proteomics and Mass Spectrometry, Max Planck Institute of Biophysics, Max-von-Laue-Straße 3, 60438, Frankfurt am Main, Germany
- Mass Spectrometry, Max Planck Institute for Brain Research, Max-von-Laue-Straße 4, 60438, Frankfurt am Main, Germany
| | - Athanasios Typas
- European Molecular Biology Laboratory, Genome Biology Unit, Meyerhofstraße 1, 69117, Heidelberg, Germany
| | - Martin Beck
- Department of Molecular Sociology, Max Planck Institute of Biophysics, Max-von-Laue-Straße 3, 60438, Frankfurt am Main, Germany.
- Institute of Biochemistry, Goethe University Frankfurt, 60438, Frankfurt am Main, Germany.
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7
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von Kügelgen A, Cassidy CK, van Dorst S, Pagani LL, Batters C, Ford Z, Löwe J, Alva V, Stansfeld PJ, Bharat TAM. Membraneless channels sieve cations in ammonia-oxidizing marine archaea. Nature 2024; 630:230-236. [PMID: 38811725 PMCID: PMC11153153 DOI: 10.1038/s41586-024-07462-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 04/24/2024] [Indexed: 05/31/2024]
Abstract
Nitrosopumilus maritimus is an ammonia-oxidizing archaeon that is crucial to the global nitrogen cycle1,2. A critical step for nitrogen oxidation is the entrapment of ammonium ions from a dilute marine environment at the cell surface and their subsequent channelling to the cell membrane of N. maritimus. Here we elucidate the structure of the molecular machinery responsible for this process, comprising the surface layer (S-layer), using electron cryotomography and subtomogram averaging from cells. We supplemented our in situ structure of the ammonium-binding S-layer array with a single-particle electron cryomicroscopy structure, revealing detailed features of this immunoglobulin-rich and glycan-decorated S-layer. Biochemical analyses showed strong ammonium binding by the cell surface, which was lost after S-layer disassembly. Sensitive bioinformatic analyses identified similar S-layers in many ammonia-oxidizing archaea, with conserved sequence and structural characteristics. Moreover, molecular simulations and structure determination of ammonium-enriched specimens enabled us to examine the cation-binding properties of the S-layer, revealing how it concentrates ammonium ions on its cell-facing side, effectively acting as a multichannel sieve on the cell membrane. This in situ structural study illuminates the biogeochemically essential process of ammonium binding and channelling, common to many marine microorganisms that are fundamental to the nitrogen cycle.
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Affiliation(s)
- Andriko von Kügelgen
- Structural Studies Division, MRC Laboratory of Molecular Biology, Cambridge, UK
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - C Keith Cassidy
- Department of Physics and Astronomy, University of Missouri-Columbia, Columbia, MO, USA
| | - Sofie van Dorst
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Lennart L Pagani
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Christopher Batters
- Protein and Nucleic Acid Chemistry Division, MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Zephyr Ford
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Jan Löwe
- Structural Studies Division, MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Vikram Alva
- Department of Protein Evolution, Max Planck Institute for Biology Tübingen, Tübingen, Germany
| | - Phillip J Stansfeld
- School of Life Sciences and Department of Chemistry, University of Warwick, Coventry, UK
| | - Tanmay A M Bharat
- Structural Studies Division, MRC Laboratory of Molecular Biology, Cambridge, UK.
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8
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Keller J, Fernández-Busnadiego R. In situ studies of membrane biology by cryo-electron tomography. Curr Opin Cell Biol 2024; 88:102363. [PMID: 38677049 DOI: 10.1016/j.ceb.2024.102363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 03/26/2024] [Accepted: 04/08/2024] [Indexed: 04/29/2024]
Abstract
Cryo-electron tomography (cryo-ET) allows high resolution 3D imaging of biological samples in near-native environments. Thus, cryo-ET has become the method of choice to analyze the unperturbed organization of cellular membranes. Here, we briefly discuss current cryo-ET workflows and their application to study membrane biology in situ, under basal and pathological conditions.
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Affiliation(s)
- Jenny Keller
- University Medical Center Göttingen, Institute for Neuropathology, Göttingen, 37077, Germany; Collaborative Research Center 1190 "Compartmental Gates and Contact Sites in Cells", University of Göttingen, Göttingen, Germany.
| | - Rubén Fernández-Busnadiego
- University Medical Center Göttingen, Institute for Neuropathology, Göttingen, 37077, Germany; Collaborative Research Center 1190 "Compartmental Gates and Contact Sites in Cells", University of Göttingen, Göttingen, Germany; Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, 37077, Germany; Faculty of Physics, University of Göttingen, Göttingen, 37077, Germany.
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9
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Schneider J, Jasnin M. Molecular architecture of the actin cytoskeleton: From single cells to whole organisms using cryo-electron tomography. Curr Opin Cell Biol 2024; 88:102356. [PMID: 38608425 DOI: 10.1016/j.ceb.2024.102356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 03/18/2024] [Accepted: 03/19/2024] [Indexed: 04/14/2024]
Abstract
Cryo-electron tomography (cryo-ET) has begun to provide intricate views of cellular architecture at unprecedented resolutions. Considerable efforts are being made to further optimize and automate the cryo-ET workflow, from sample preparation to data acquisition and analysis, to enable visual proteomics inside of cells. Here, we will discuss the latest advances in cryo-ET that go hand in hand with their application to the actin cytoskeleton. The development of deep learning tools for automated annotation of tomographic reconstructions and the serial lift-out sample preparation procedure will soon make it possible to perform high-resolution structural biology in a whole new range of samples, from multicellular organisms to organoids and tissues.
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Affiliation(s)
- Jonathan Schneider
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany; Helmholtz Pioneer Campus, Helmholtz Munich, 85764 Neuherberg, Germany
| | - Marion Jasnin
- Helmholtz Pioneer Campus, Helmholtz Munich, 85764 Neuherberg, Germany; Department of Chemistry, Technical University of Munich, 85748 Garching, Germany.
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10
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Siggel M, Jensen RK, Maurer VJ, Mahamid J, Kosinski J. ColabSeg: An interactive tool for editing, processing, and visualizing membrane segmentations from cryo-ET data. J Struct Biol 2024; 216:108067. [PMID: 38367824 DOI: 10.1016/j.jsb.2024.108067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 01/17/2024] [Accepted: 02/03/2024] [Indexed: 02/19/2024]
Abstract
Cellular cryo-electron tomography (cryo-ET) has emerged as a key method to unravel the spatial and structural complexity of cells in their near-native state at unprecedented molecular resolution. To enable quantitative analysis of the complex shapes and morphologies of lipid membranes, the noisy three-dimensional (3D) volumes must be segmented. Despite recent advances, this task often requires considerable user intervention to curate the resulting segmentations. Here, we present ColabSeg, a Python-based tool for processing, visualizing, editing, and fitting membrane segmentations from cryo-ET data for downstream analysis. ColabSeg makes many well-established algorithms for point-cloud processing easily available to the broad community of structural biologists for applications in cryo-ET through its graphical user interface (GUI). We demonstrate the usefulness of the tool with a range of use cases and biological examples. Finally, for a large Mycoplasma pneumoniae dataset of 50 tomograms, we show how ColabSeg enables high-throughput membrane segmentation, which can be used as valuable training data for fully automated convolutional neural network (CNN)-based segmentation.
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Affiliation(s)
- Marc Siggel
- European Molecular Biology Laboratory (EMBL) Hamburg, Notkestrasse 85, Hamburg 20607, Germany; Centre of Structural Systems Biology (CSSB), Notkestrasse 85, Hamburg 20607, Germany
| | - Rasmus K Jensen
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL) Heidelberg, Meyerhofstrasse 1, Heidelberg 69117, Germany
| | - Valentin J Maurer
- European Molecular Biology Laboratory (EMBL) Hamburg, Notkestrasse 85, Hamburg 20607, Germany; Centre of Structural Systems Biology (CSSB), Notkestrasse 85, Hamburg 20607, Germany
| | - Julia Mahamid
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL) Heidelberg, Meyerhofstrasse 1, Heidelberg 69117, Germany; Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL) Heidelberg, Meyerhofstrasse 1, Heidelberg 69117, Germany
| | - Jan Kosinski
- European Molecular Biology Laboratory (EMBL) Hamburg, Notkestrasse 85, Hamburg 20607, Germany; Centre of Structural Systems Biology (CSSB), Notkestrasse 85, Hamburg 20607, Germany; Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL) Heidelberg, Meyerhofstrasse 1, Heidelberg 69117, Germany.
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11
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Galaz-Montoya JG. The advent of preventive high-resolution structural histopathology by artificial-intelligence-powered cryogenic electron tomography. Front Mol Biosci 2024; 11:1390858. [PMID: 38868297 PMCID: PMC11167099 DOI: 10.3389/fmolb.2024.1390858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2024] [Accepted: 05/08/2024] [Indexed: 06/14/2024] Open
Abstract
Advances in cryogenic electron microscopy (cryoEM) single particle analysis have revolutionized structural biology by facilitating the in vitro determination of atomic- and near-atomic-resolution structures for fully hydrated macromolecular complexes exhibiting compositional and conformational heterogeneity across a wide range of sizes. Cryogenic electron tomography (cryoET) and subtomogram averaging are rapidly progressing toward delivering similar insights for macromolecular complexes in situ, without requiring tags or harsh biochemical purification. Furthermore, cryoET enables the visualization of cellular and tissue phenotypes directly at molecular, nanometric resolution without chemical fixation or staining artifacts. This forward-looking review covers recent developments in cryoEM/ET and related technologies such as cryogenic focused ion beam milling scanning electron microscopy and correlative light microscopy, increasingly enhanced and supported by artificial intelligence algorithms. Their potential application to emerging concepts is discussed, primarily the prospect of complementing medical histopathology analysis. Machine learning solutions are poised to address current challenges posed by "big data" in cryoET of tissues, cells, and macromolecules, offering the promise of enabling novel, quantitative insights into disease processes, which may translate into the clinic and lead to improved diagnostics and targeted therapeutics.
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Affiliation(s)
- Jesús G. Galaz-Montoya
- Department of Bioengineering, James H. Clark Center, Stanford University, Stanford, CA, United States
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12
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Kong WW, Zhu Y, Zhao HR, Du K, Zhou RQ, Li B, Yang F, Hou P, Huang XH, Chen Y, Wang YC, Sun F, Jiang YL, Zhou CZ. Cryo-electron tomography reveals the packaging pattern of RuBisCOs in Synechococcus β-carboxysome. Structure 2024:S0969-2126(24)00184-9. [PMID: 38823379 DOI: 10.1016/j.str.2024.05.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 04/01/2024] [Accepted: 05/07/2024] [Indexed: 06/03/2024]
Abstract
Carboxysomes are large self-assembled microcompartments that serve as the central machinery of a CO2-concentrating mechanism (CCM). Biogenesis of carboxysome requires the fine organization of thousands of individual proteins; however, the packaging pattern of internal RuBisCOs remains largely unknown. Here we purified the intact β-carboxysomes from Synechococcus elongatus PCC 7942 and identified the protein components by mass spectrometry. Cryo-electron tomography combined with subtomogram averaging revealed the general organization pattern of internal RuBisCOs, in which the adjacent RuBisCOs are mainly arranged in three distinct manners: head-to-head, head-to-side, and side-by-side. The RuBisCOs in the outermost layer are regularly aligned along the shell, the majority of which directly interact with the shell. Moreover, statistical analysis enabled us to propose an ideal packaging model of RuBisCOs in the β-carboxysome. These results provide new insights into the biogenesis of β-carboxysomes and also advance our understanding of the efficient carbon fixation functionality of carboxysomes.
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Affiliation(s)
- Wen-Wen Kong
- School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China
| | - Yun Zhu
- National Key Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Heng-Rui Zhao
- School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China
| | - Kang Du
- School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China
| | - Rui-Qian Zhou
- School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China
| | - Bo Li
- School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China
| | - Feng Yang
- School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China
| | - Pu Hou
- School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China
| | - Xia-He Huang
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yuxing Chen
- School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China
| | - Ying-Chun Wang
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Fei Sun
- National Key Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
| | - Yong-Liang Jiang
- School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China.
| | - Cong-Zhao Zhou
- School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China.
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13
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Kyrilis FL, Low JKK, Mackay JP, Kastritis PL. Structural biology in cellulo: Minding the gap between conceptualization and realization. Curr Opin Struct Biol 2024; 87:102843. [PMID: 38788606 DOI: 10.1016/j.sbi.2024.102843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Revised: 04/30/2024] [Accepted: 05/01/2024] [Indexed: 05/26/2024]
Abstract
Recent technological advances have deepened our perception of cellular structure. However, most structural data doesn't originate from intact cells, limiting our understanding of cellular processes. Here, we discuss current and future developments that will bring us towards a structural picture of the cell. Electron cryotomography is the standard bearer, with its ability to provide in cellulo snapshots. Single-particle electron microscopy (of purified biomolecules and of complex mixtures) and covalent crosslinking combined with mass spectrometry also have significant roles to play, as do artificial intelligence algorithms in their many guises. To integrate these multiple approaches, data curation and standardisation will be critical - as is the need to expand efforts beyond our current protein-centric view to the other (macro)molecules that sustain life.
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Affiliation(s)
- Fotis L Kyrilis
- Institute of Chemical Biology, National Hellenic Research Foundation, Athens, Greece. https://twitter.com/Fotansky_16
| | - Jason K K Low
- School of Life and Environmental Sciences, University of Sydney, Sydney, NSW 2006, Australia
| | - Joel P Mackay
- School of Life and Environmental Sciences, University of Sydney, Sydney, NSW 2006, Australia.
| | - Panagiotis L Kastritis
- Institute of Chemical Biology, National Hellenic Research Foundation, Athens, Greece; Interdisciplinary Research Center HALOmem, Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Straße 3a, Halle/Saale, Germany; Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Straße 3, Halle/Saale, Germany; Biozentrum, Martin Luther University Halle-Wittenberg, Weinbergweg 22, Halle/Saale, Germany.
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14
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Van Veen D, Galaz-Montoya JG, Shen L, Baldwin P, Chaudhari AS, Lyumkis D, Schmid MF, Chiu W, Pauly J. Missing Wedge Completion via Unsupervised Learning with Coordinate Networks. Int J Mol Sci 2024; 25:5473. [PMID: 38791508 PMCID: PMC11121946 DOI: 10.3390/ijms25105473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Revised: 04/29/2024] [Accepted: 04/30/2024] [Indexed: 05/26/2024] Open
Abstract
Cryogenic electron tomography (cryoET) is a powerful tool in structural biology, enabling detailed 3D imaging of biological specimens at a resolution of nanometers. Despite its potential, cryoET faces challenges such as the missing wedge problem, which limits reconstruction quality due to incomplete data collection angles. Recently, supervised deep learning methods leveraging convolutional neural networks (CNNs) have considerably addressed this issue; however, their pretraining requirements render them susceptible to inaccuracies and artifacts, particularly when representative training data is scarce. To overcome these limitations, we introduce a proof-of-concept unsupervised learning approach using coordinate networks (CNs) that optimizes network weights directly against input projections. This eliminates the need for pretraining, reducing reconstruction runtime by 3-20× compared to supervised methods. Our in silico results show improved shape completion and reduction of missing wedge artifacts, assessed through several voxel-based image quality metrics in real space and a novel directional Fourier Shell Correlation (FSC) metric. Our study illuminates benefits and considerations of both supervised and unsupervised approaches, guiding the development of improved reconstruction strategies.
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Affiliation(s)
- Dave Van Veen
- Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA;
| | - Jesús G. Galaz-Montoya
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA; (J.G.G.-M.); (W.C.)
| | - Liyue Shen
- Department of Electrical and Computer Engineering, University of Michigan, Ann Arbor, MI 48109, USA;
| | - Philip Baldwin
- Department of Biochemistry and Molecular Pharmacology, Baylor College of Medicine, Houston, TX 77030, USA;
- Department of Genetics, The Salk Institute of Biological Sciences, La Jolla, CA 92037, USA;
| | | | - Dmitry Lyumkis
- Department of Genetics, The Salk Institute of Biological Sciences, La Jolla, CA 92037, USA;
- Graduate School of Biological Sciences, University of California San Diego, La Jolla, CA 92037, USA
| | - Michael F. Schmid
- Division of CryoEM and Bioimaging, SSRL, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA;
| | - Wah Chiu
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA; (J.G.G.-M.); (W.C.)
- Division of CryoEM and Bioimaging, SSRL, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA;
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - John Pauly
- Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA;
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15
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Wang H, Liao S, Yu X, Zhang J, Zhou ZH. TomoNet: A streamlined cryogenic electron tomography software pipeline with automatic particle picking on flexible lattices. BIOLOGICAL IMAGING 2024; 4:e7. [PMID: 38828212 PMCID: PMC11140495 DOI: 10.1017/s2633903x24000060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 03/04/2024] [Accepted: 03/25/2024] [Indexed: 06/05/2024]
Abstract
Cryogenic electron tomography (cryoET) is capable of determining in situ biological structures of molecular complexes at near-atomic resolution by averaging half a million subtomograms. While abundant complexes/particles are often clustered in arrays, precisely locating and seamlessly averaging such particles across many tomograms present major challenges. Here, we developed TomoNet, a software package with a modern graphical user interface to carry out the entire pipeline of cryoET and subtomogram averaging to achieve high resolution. TomoNet features built-in automatic particle picking and three-dimensional (3D) classification functions and integrates commonly used packages to streamline high-resolution subtomogram averaging for structures in 1D, 2D, or 3D arrays. Automatic particle picking is accomplished in two complementary ways: one based on template matching and the other using deep learning. TomoNet's hierarchical file organization and visual display facilitate efficient data management as required for large cryoET datasets. Applications of TomoNet to three types of datasets demonstrate its capability of efficient and accurate particle picking on flexible and imperfect lattices to obtain high-resolution 3D biological structures: virus-like particles, bacterial surface layers within cellular lamellae, and membranes decorated with nuclear egress protein complexes. These results demonstrate TomoNet's potential for broad applications to various cryoET projects targeting high-resolution in situ structures.
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Affiliation(s)
- Hui Wang
- Department of Bioengineering, University of California, Los Angeles (UCLA), Los Angeles, CA, USA
- California NanoSystems Institute, UCLA, Los Angeles, CA, USA
- Department of Microbiology, Immunology, and Molecular Genetics, UCLA, Los Angeles, CA, USA
| | - Shiqing Liao
- California NanoSystems Institute, UCLA, Los Angeles, CA, USA
- Department of Microbiology, Immunology, and Molecular Genetics, UCLA, Los Angeles, CA, USA
| | - Xinye Yu
- Department of Microbiology, Immunology, and Molecular Genetics, UCLA, Los Angeles, CA, USA
| | - Jiayan Zhang
- California NanoSystems Institute, UCLA, Los Angeles, CA, USA
- Department of Microbiology, Immunology, and Molecular Genetics, UCLA, Los Angeles, CA, USA
| | - Z. Hong Zhou
- Department of Bioengineering, University of California, Los Angeles (UCLA), Los Angeles, CA, USA
- California NanoSystems Institute, UCLA, Los Angeles, CA, USA
- Department of Microbiology, Immunology, and Molecular Genetics, UCLA, Los Angeles, CA, USA
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16
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Gao J, Tong M, Lee C, Gaertig J, Legal T, Bui KH. DomainFit: Identification of protein domains in cryo-EM maps at intermediate resolution using AlphaFold2-predicted models. Structure 2024:S0969-2126(24)00143-6. [PMID: 38754431 DOI: 10.1016/j.str.2024.04.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 03/18/2024] [Accepted: 04/19/2024] [Indexed: 05/18/2024]
Abstract
Cryoelectron microscopy (cryo-EM) has revolutionized the structural determination of macromolecular complexes. With the paradigm shift to structure determination of highly complex endogenous macromolecular complexes ex vivo and in situ structural biology, there are an increasing number of structures of native complexes. These complexes often contain unidentified proteins, related to different cellular states or processes. Identifying proteins at resolutions lower than 4 Å remains challenging because side chains cannot be visualized reliably. Here, we present DomainFit, a program for semi-automated domain-level protein identification from cryo-EM maps, particularly at resolutions lower than 4 Å. By fitting domains from AlphaFold2-predicted models into cryo-EM maps, the program performs statistical analyses and attempts to identify the domains and protein candidates forming the density. Using DomainFit, we identified two microtubule inner proteins, one of which contains a CCDC81 domain and is exclusively localized in the proximal region of the doublet microtubule in Tetrahymena thermophila.
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Affiliation(s)
- Jerry Gao
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, McGill University, Montréal, QC H3A 0C7, Canada; Centre de recherche en biologie structurale, McGill University, Montréal, QC H3G 0B1, Canada
| | - Maxwell Tong
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, McGill University, Montréal, QC H3A 0C7, Canada; Centre de recherche en biologie structurale, McGill University, Montréal, QC H3G 0B1, Canada
| | - Chinkyu Lee
- Department of Cellular Biology, University of Georgia, Athens 30602-2607, GA, USA
| | - Jacek Gaertig
- Department of Cellular Biology, University of Georgia, Athens 30602-2607, GA, USA
| | - Thibault Legal
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, McGill University, Montréal, QC H3A 0C7, Canada; Centre de recherche en biologie structurale, McGill University, Montréal, QC H3G 0B1, Canada.
| | - Khanh Huy Bui
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, McGill University, Montréal, QC H3A 0C7, Canada; Centre de recherche en biologie structurale, McGill University, Montréal, QC H3G 0B1, Canada.
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17
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Khavnekar S, Wan W. TOMOMAN: a software package for large scale cryo-electron tomography data preprocessing, community data sharing, and collaborative computing. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.02.589639. [PMID: 38746401 PMCID: PMC11092592 DOI: 10.1101/2024.05.02.589639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Cryo-electron tomography (cryo-ET) and subtomogram averaging (STA) are becoming the preferred methodologies for investigating subcellular and macromolecular structures in native or near-native environments. While cryo-ET is amenable to a wide range of biological problems, these problems often have data processing requirements that need to be individually optimized, precluding the notion of a one-size-fits-all processing pipeline. Cryo-ET data processing is also becoming progressively more complex due to an increasing number of packages for each processing step. Though each package has its own strengths and weaknesses, independent development and different data formats makes them difficult to interface with one another. TOMOMAN (TOMOgram MANager) is an extensible package for streamlining the interoperability of packages, enabling users to develop project-specific processing workflows. TOMOMAN does this by maintaining an internal metadata format and wrapping external packages to manage and perform preprocessing, from raw tilt-series data to reconstructed tomograms. TOMOMAN can also export this metadata between various STA packages. TOMOMAN also includes tools for archiving projects to data repositories; allowing subsequent users to download TOMOMAN projects and directly resume processing where it was previously left off. By tracking essential metadata, TOMOMAN streamlines data sharing, which improves reproducibility of published results, reduces computational costs by minimizing reprocessing, and enables distributed cryo-ET projects between multiple groups and institutions. TOMOMAN provides a way for users to test different software packages to develop processing workflows that meet the specific needs of their biological questions and to distribute their results with the broader scientific community.
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18
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Wan W, Khavnekar S, Wagner J. STOPGAP: an open-source package for template matching, subtomogram alignment and classification. Acta Crystallogr D Struct Biol 2024; 80:336-349. [PMID: 38606666 PMCID: PMC11066880 DOI: 10.1107/s205979832400295x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Accepted: 04/05/2024] [Indexed: 04/13/2024] Open
Abstract
Cryo-electron tomography (cryo-ET) enables molecular-resolution 3D imaging of complex biological specimens such as viral particles, cellular sections and, in some cases, whole cells. This enables the structural characterization of molecules in their near-native environments, without the need for purification or separation, thereby preserving biological information such as conformational states and spatial relationships between different molecular species. Subtomogram averaging is an image-processing workflow that allows users to leverage cryo-ET data to identify and localize target molecules, determine high-resolution structures of repeating molecular species and classify different conformational states. Here, STOPGAP, an open-source package for subtomogram averaging that is designed to provide users with fine control over each of these steps, is described. In providing detailed descriptions of the image-processing algorithms that STOPGAP uses, this manuscript is also intended to serve as a technical resource to users as well as for further community-driven software development.
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Affiliation(s)
- William Wan
- Department of Biochemistry and Center for Structural Biology, Vanderbilt University, Nashville, TN 37240, USA
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19
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Gaifas L, Kirchner MA, Timmins J, Gutsche I. Blik is an extensible 3D visualisation tool for the annotation and analysis of cryo-electron tomography data. PLoS Biol 2024; 22:e3002447. [PMID: 38687779 DOI: 10.1371/journal.pbio.3002447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 04/02/2024] [Indexed: 05/02/2024] Open
Abstract
Powerful, workflow-agnostic and interactive visualisation is essential for the ad hoc, human-in-the-loop workflows typical of cryo-electron tomography (cryo-ET). While several tools exist for visualisation and annotation of cryo-ET data, they are often integrated as part of monolithic processing pipelines, or focused on a specific task and offering limited reusability and extensibility. With each software suite presenting its own pros and cons and tools tailored to address specific challenges, seamless integration between available pipelines is often a difficult task. As part of the effort to enable such flexibility and move the software ecosystem towards a more collaborative and modular approach, we developed blik, an open-source napari plugin for visualisation and annotation of cryo-ET data (source code: https://github.com/brisvag/blik). blik offers fast, interactive, and user-friendly 3D visualisation thanks to napari, and is built with extensibility and modularity at the core. Data is handled and exposed through well-established scientific Python libraries such as numpy arrays and pandas dataframes. Reusable components (such as data structures, file read/write, and annotation tools) are developed as independent Python libraries to encourage reuse and community contribution. By easily integrating with established image analysis tools-even outside of the cryo-ET world-blik provides a versatile platform for interacting with cryo-ET data. On top of core visualisation features-interactive and simultaneous visualisation of tomograms, particle picks, and segmentations-blik provides an interface for interactive tools such as manual, surface-based and filament-based particle picking, and image segmentation, as well as simple filtering tools. Additional self-contained napari plugins developed as part of this work also implement interactive plotting and selection based on particle features, and label interpolation for easier segmentation. Finally, we highlight the differences with existing software and showcase blik's applicability in biological research.
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Affiliation(s)
- Lorenzo Gaifas
- Institut de Biologie Structurale, Université Grenoble Alpes, CEA, CNRS, IBS, Grenoble, France
| | - Moritz A Kirchner
- Institut de Biologie Structurale, Université Grenoble Alpes, CEA, CNRS, IBS, Grenoble, France
| | - Joanna Timmins
- Institut de Biologie Structurale, Université Grenoble Alpes, CEA, CNRS, IBS, Grenoble, France
| | - Irina Gutsche
- Institut de Biologie Structurale, Université Grenoble Alpes, CEA, CNRS, IBS, Grenoble, France
- Department of Chemistry, Umeå University, Umeå, Sweden
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20
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Sharma KD, Doktorova M, Waxham MN, Heberle FA. Cryo-EM images of phase-separated lipid bilayer vesicles analyzed with a machine-learning approach. Biophys J 2024:S0006-3495(24)00291-1. [PMID: 38689500 DOI: 10.1016/j.bpj.2024.04.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 03/08/2024] [Accepted: 04/26/2024] [Indexed: 05/02/2024] Open
Abstract
Lateral lipid heterogeneity (i.e., raft formation) in biomembranes plays a functional role in living cells. Three-component mixtures of low- and high-melting lipids plus cholesterol offer a simplified experimental model for raft domains in which a liquid-disordered (Ld) phase coexists with a liquid-ordered (Lo) phase. Using such models, we recently showed that cryogenic electron microscopy (cryo-EM) can detect phase separation in lipid vesicles based on differences in bilayer thickness. However, the considerable noise within cryo-EM data poses a significant challenge for accurately determining the membrane phase state at high spatial resolution. To this end, we have developed an image-processing pipeline that utilizes machine learning (ML) to predict the bilayer phase in projection images of lipid vesicles. Importantly, the ML method exploits differences in both the thickness and molecular density of Lo compared to Ld, which leads to improved phase identification. To assess accuracy, we used artificial images of phase-separated lipid vesicles generated from all-atom molecular dynamics simulations of Lo and Ld phases. Synthetic ground-truth data sets mimicking a series of compositions along a tieline of Ld + Lo coexistence were created and then analyzed with various ML models. For all tieline compositions, we find that the ML approach can correctly identify the bilayer phase with >90% accuracy, thus providing a means to isolate the intensity profiles of coexisting Ld and Lo phases, as well as accurately determine domain-size distributions, number of domains, and phase-area fractions. The method described here provides a framework for characterizing nanoscopic lateral heterogeneities in membranes and paves the way for a more detailed understanding of raft properties in biological contexts.
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Affiliation(s)
- Karan D Sharma
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee
| | - Milka Doktorova
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia
| | - M Neal Waxham
- Department of Neurobiology and Anatomy, University of Texas Health Science Center, Houston, Texas
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21
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Van Veen D, Galaz-Montoya JG, Shen L, Baldwin P, Chaudhari AS, Lyumkis D, Schmid MF, Chiu W, Pauly J. Missing Wedge Completion via Unsupervised Learning with Coordinate Networks. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.12.589090. [PMID: 38712113 PMCID: PMC11071277 DOI: 10.1101/2024.04.12.589090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Cryogenic electron tomography (cryoET) is a powerful tool in structural biology, enabling detailed 3D imaging of biological specimens at a resolution of nanometers. Despite its potential, cryoET faces challenges such as the missing wedge problem, which limits reconstruction quality due to incomplete data collection angles. Recently, supervised deep learning methods leveraging convolutional neural networks (CNNs) have considerably addressed this issue; however, their pretraining requirements render them susceptible to inaccuracies and artifacts, particularly when representative training data is scarce. To overcome these limitations, we introduce a proof-of-concept unsupervised learning approach using coordinate networks (CNs) that optimizes network weights directly against input projections. This eliminates the need for pretraining, reducing reconstruction runtime by 3 - 20× compared to supervised methods. Our in silico results show improved shape completion and reduction of missing wedge artifacts, assessed through several voxel-based image quality metrics in real space and a novel directional Fourier Shell Correlation (FSC) metric. Our study illuminates benefits and considerations of both supervised and unsupervised approaches, guiding the development of improved reconstruction strategies.
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Affiliation(s)
- Dave Van Veen
- Dept. of Electrical Engineering, Stanford University
| | | | - Liyue Shen
- Dept. of Electrical and Computer Engineering, University of Michigan
| | - Philip Baldwin
- Dept. of Biochemistry and Molecular Pharmacology, Baylor College of Medicine
- Dept. of Genetics, The Salk Institute for Biological Sciences
| | | | - Dmitry Lyumkis
- Dept. of Genetics, The Salk Institute for Biological Sciences
- Graduate School of Biological Sciences, University of California San Diego
| | - Michael F. Schmid
- Division of CryoEM and Bioimaging, SSRL, SLAC National Accelerator Laboratory
| | - Wah Chiu
- Dept. of Bioengineering, Stanford University
- Division of CryoEM and Bioimaging, SSRL, SLAC National Accelerator Laboratory
- Dept. of Microbiology and Immunology, Stanford University
| | - John Pauly
- Dept. of Electrical Engineering, Stanford University
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22
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Tuijtel MW, Cruz-León S, Kreysing JP, Welsch S, Hummer G, Beck M, Turoňová B. Thinner is not always better: Optimizing cryo-lamellae for subtomogram averaging. SCIENCE ADVANCES 2024; 10:eadk6285. [PMID: 38669330 PMCID: PMC11051657 DOI: 10.1126/sciadv.adk6285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 03/26/2024] [Indexed: 04/28/2024]
Abstract
Cryo-electron tomography (cryo-ET) is a powerful method to elucidate subcellular architecture and to structurally analyze biomolecules in situ by subtomogram averaging, yet data quality critically depends on specimen thickness. Cells that are too thick for transmission imaging can be thinned into lamellae by cryo-focused ion beam (cryo-FIB) milling. Despite being a crucial parameter directly affecting attainable resolution, optimal lamella thickness has not been systematically investigated nor the extent of structural damage caused by gallium ions used for FIB milling. We thus systematically determined how resolution is affected by these parameters. We find that ion-induced damage does not affect regions more than 30 nanometers from either lamella surface and that up to ~180-nanometer lamella thickness does not negatively affect resolution. This shows that there is no need to generate very thin lamellae and lamella thickness can be chosen such that it captures cellular features of interest, thereby opening cryo-ET also for studies of large complexes.
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Affiliation(s)
- Maarten W. Tuijtel
- Department of Molecular Sociology, Max Planck Institute of Biophysics, Max-von-Laue-Straße 3, 60438 Frankfurt am Main, Germany
| | - Sergio Cruz-León
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Max-von-Laue-Straße 3, 60438 Frankfurt am Main, Germany
| | - Jan Philipp Kreysing
- Department of Molecular Sociology, Max Planck Institute of Biophysics, Max-von-Laue-Straße 3, 60438 Frankfurt am Main, Germany
- IMPRS on Cellular Biophysics, Max-von-Laue-Straße 3, 60438 Frankfurt am Main, Germany
| | - Sonja Welsch
- Central Electron Microscopy Facility, Max Planck Institute of Biophysics, Max-von-Laue-Straße 3, 60438 Frankfurt am Main, Germany
| | - Gerhard Hummer
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Max-von-Laue-Straße 3, 60438 Frankfurt am Main, Germany
- Institute of Biophysics, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
| | - Martin Beck
- Department of Molecular Sociology, Max Planck Institute of Biophysics, Max-von-Laue-Straße 3, 60438 Frankfurt am Main, Germany
- Institute of Biochemistry, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
| | - Beata Turoňová
- Department of Molecular Sociology, Max Planck Institute of Biophysics, Max-von-Laue-Straße 3, 60438 Frankfurt am Main, Germany
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23
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Liu YT, Fan H, Hu JJ, Zhou ZH. Overcoming the preferred orientation problem in cryoEM with self-supervised deep-learning. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.11.588921. [PMID: 38645074 PMCID: PMC11030451 DOI: 10.1101/2024.04.11.588921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
While advances in single-particle cryoEM have enabled the structural determination of macromolecular complexes at atomic resolution, particle orientation bias (the so-called "preferred" orientation problem) remains a complication for most specimens. Existing solutions have relied on biochemical and physical strategies applied to the specimen and are often complex and challenging. Here, we develop spIsoNet, an end-to-end self-supervised deep-learning-based software to address the preferred orientation problem. Using preferred-orientation views to recover molecular information in under-sampled views, spIsoNet improves both angular isotropy and particle alignment accuracy during 3D reconstruction. We demonstrate spIsoNet's capability of generating near-isotropic reconstructions from representative biological systems with limited views, including ribosomes, β-galactosidases, and a previously intractable hemagglutinin trimer dataset. spIsoNet can also be generalized to improve map isotropy and particle alignment of preferentially oriented molecules in subtomogram averaging. Therefore, without additional specimen-preparation procedures, spIsoNet provides a general computational solution to the preferred orientation problem.
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Affiliation(s)
- Yun-Tao Liu
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, CA, USA
- California NanoSystems Institute, University of California, Los Angeles, CA, USA
| | - Hongcheng Fan
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, CA, USA
- California NanoSystems Institute, University of California, Los Angeles, CA, USA
| | - Jason J. Hu
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, CA, USA
- California NanoSystems Institute, University of California, Los Angeles, CA, USA
- Current address: Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Z. Hong Zhou
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, CA, USA
- California NanoSystems Institute, University of California, Los Angeles, CA, USA
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24
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Homola M, Büttner CR, Füzik T, Křepelka P, Holbová R, Nováček J, Chaillet ML, Žák J, Grybchuk D, Förster F, Wilson WH, Schroeder DC, Plevka P. Structure and replication cycle of a virus infecting climate-modulating alga Emiliania huxleyi. SCIENCE ADVANCES 2024; 10:eadk1954. [PMID: 38598627 PMCID: PMC11006232 DOI: 10.1126/sciadv.adk1954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 03/06/2024] [Indexed: 04/12/2024]
Abstract
The globally distributed marine alga Emiliania huxleyi has cooling effect on the Earth's climate. The population density of E. huxleyi is restricted by Nucleocytoviricota viruses, including E. huxleyi virus 201 (EhV-201). Despite the impact of E. huxleyi viruses on the climate, there is limited information about their structure and replication. Here, we show that the dsDNA genome inside the EhV-201 virion is protected by an inner membrane, capsid, and outer membrane. EhV-201 virions infect E. huxleyi by using fivefold vertices to bind to and fuse the virus' inner membrane with the cell plasma membrane. Progeny virions assemble in the cytoplasm at the surface of endoplasmic reticulum-derived membrane segments. Genome packaging initiates synchronously with the capsid assembly and completes through an aperture in the forming capsid. The genome-filled capsids acquire an outer membrane by budding into intracellular vesicles. EhV-201 infection induces a loss of surface protective layers from E. huxleyi cells, which enables the continuous release of virions by exocytosis.
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Affiliation(s)
- Miroslav Homola
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Carina R. Büttner
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Tibor Füzik
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Pavel Křepelka
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Radka Holbová
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Jiří Nováček
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Marten L. Chaillet
- Bijvoet Centre for Biomolecular Research, Utrecht University, Utrecht, Netherlands
| | - Jakub Žák
- Department of Botany and Zoology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Danyil Grybchuk
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Friedrich Förster
- Bijvoet Centre for Biomolecular Research, Utrecht University, Utrecht, Netherlands
| | - William H. Wilson
- Marine Biological Association, Plymouth, UK
- School of Biological and Marine Sciences, University of Plymouth, Plymouth, UK
| | | | - Pavel Plevka
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
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25
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Dendooven T, Yatskevich S, Burt A, Chen ZA, Bellini D, Rappsilber J, Kilmartin JV, Barford D. Structure of the native γ-tubulin ring complex capping spindle microtubules. Nat Struct Mol Biol 2024:10.1038/s41594-024-01281-y. [PMID: 38609662 DOI: 10.1038/s41594-024-01281-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Accepted: 03/19/2024] [Indexed: 04/14/2024]
Abstract
Microtubule (MT) filaments, composed of α/β-tubulin dimers, are fundamental to cellular architecture, function and organismal development. They are nucleated from MT organizing centers by the evolutionarily conserved γ-tubulin ring complex (γTuRC). However, the molecular mechanism of nucleation remains elusive. Here we used cryo-electron tomography to determine the structure of the native γTuRC capping the minus end of a MT in the context of enriched budding yeast spindles. In our structure, γTuRC presents a ring of γ-tubulin subunits to seed nucleation of exclusively 13-protofilament MTs, adopting an active closed conformation to function as a perfect geometric template for MT nucleation. Our cryo-electron tomography reconstruction revealed that a coiled-coil protein staples the first row of α/β-tubulin of the MT to alternating positions along the γ-tubulin ring of γTuRC. This positioning of α/β-tubulin onto γTuRC suggests a role for the coiled-coil protein in augmenting γTuRC-mediated MT nucleation. Based on our results, we describe a molecular model for budding yeast γTuRC activation and MT nucleation.
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Affiliation(s)
| | - Stanislau Yatskevich
- MRC Laboratory of Molecular Biology, Cambridge, UK.
- Genentech, South San Francisco, CA, USA.
| | - Alister Burt
- MRC Laboratory of Molecular Biology, Cambridge, UK
- Genentech, South San Francisco, CA, USA
| | - Zhuo A Chen
- Technische Universität Berlin, Chair of Bioanalytics, Berlin, Germany
| | - Dom Bellini
- MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Juri Rappsilber
- Technische Universität Berlin, Chair of Bioanalytics, Berlin, Germany
- Si-M/'Der Simulierte Mensch', Technische Universität Berlin and Charité, Universitätsmedizin Berlin, Berlin, Germany
- Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
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26
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Nogales E, Mahamid J. Bridging structural and cell biology with cryo-electron microscopy. Nature 2024; 628:47-56. [PMID: 38570716 PMCID: PMC11211576 DOI: 10.1038/s41586-024-07198-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 02/13/2024] [Indexed: 04/05/2024]
Abstract
Most life scientists would agree that understanding how cellular processes work requires structural knowledge about the macromolecules involved. For example, deciphering the double-helical nature of DNA revealed essential aspects of how genetic information is stored, copied and repaired. Yet, being reductionist in nature, structural biology requires the purification of large amounts of macromolecules, often trimmed off larger functional units. The advent of cryogenic electron microscopy (cryo-EM) greatly facilitated the study of large, functional complexes and generally of samples that are hard to express, purify and/or crystallize. Nevertheless, cryo-EM still requires purification and thus visualization outside of the natural context in which macromolecules operate and coexist. Conversely, cell biologists have been imaging cells using a number of fast-evolving techniques that keep expanding their spatial and temporal reach, but always far from the resolution at which chemistry can be understood. Thus, structural and cell biology provide complementary, yet unconnected visions of the inner workings of cells. Here we discuss how the interplay between cryo-EM and cryo-electron tomography, as a connecting bridge to visualize macromolecules in situ, holds great promise to create comprehensive structural depictions of macromolecules as they interact in complex mixtures or, ultimately, inside the cell itself.
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Affiliation(s)
- Eva Nogales
- Molecular and Cell Biology Department, Institute for Quantitative Biomedicine, University of California, Berkeley, CA, USA.
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
- Howard Hughes Medical Institute, Berkeley, CA, USA.
| | - Julia Mahamid
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany.
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany.
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27
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Singh D, Soni N, Hutchings J, Echeverria I, Shaikh F, Duquette M, Suslov S, Li Z, van Eeuwen T, Molloy K, Shi Y, Wang J, Guo Q, Chait BT, Fernandez-Martinez J, Rout MP, Sali A, Villa E. The Molecular Architecture of the Nuclear Basket. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.27.587068. [PMID: 38586009 PMCID: PMC10996695 DOI: 10.1101/2024.03.27.587068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
The nuclear pore complex (NPC) is the sole mediator of nucleocytoplasmic transport. Despite great advances in understanding its conserved core architecture, the peripheral regions can exhibit considerable variation within and between species. One such structure is the cage-like nuclear basket. Despite its crucial roles in mRNA surveillance and chromatin organization, an architectural understanding has remained elusive. Using in-cell cryo-electron tomography and subtomogram analysis, we explored the NPC's structural variations and the nuclear basket across fungi (yeast; S. cerevisiae), mammals (mouse; M. musculus), and protozoa (T. gondii). Using integrative structural modeling, we computed a model of the basket in yeast and mammals that revealed how a hub of Nups in the nuclear ring binds to basket-forming Mlp/Tpr proteins: the coiled-coil domains of Mlp/Tpr form the struts of the basket, while their unstructured termini constitute the basket distal densities, which potentially serve as a docking site for mRNA preprocessing before nucleocytoplasmic transport.
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Affiliation(s)
- Digvijay Singh
- School of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Neelesh Soni
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA, USA
| | - Joshua Hutchings
- School of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Ignacia Echeverria
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Farhaz Shaikh
- School of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Madeleine Duquette
- School of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Sergey Suslov
- School of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Zhixun Li
- State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, School of Life Sciences, Peking University, Beijing 100871, P. R. China
| | - Trevor van Eeuwen
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, NY 10065, USA
| | - Kelly Molloy
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, NY 10065, USA
| | - Yi Shi
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, NY 10065, USA
| | - Junjie Wang
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, NY 10065, USA
| | - Qiang Guo
- State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, School of Life Sciences, Peking University, Beijing 100871, P. R. China
| | - Brian T Chait
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, NY 10065, USA
| | - Javier Fernandez-Martinez
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, NY 10065, USA
- Ikerbasque, Basque Foundation for Science, 48013 Bilbao, Spain
- Instituto Biofisika (UPV/EHU, CSIC), University of the Basque Country, 48940 Leioa, Spain
| | - Michael P Rout
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, NY 10065, USA
| | - Andrej Sali
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA, USA
- Quantitative Biosciences Institute, University of California, San Francisco, San Francisco, CA 94158, USA
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Elizabeth Villa
- School of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
- Howard Hughes Medical Institute, University of California San Diego, La Jolla, CA 92093, USA
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28
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Powell BM, Brant TS, Davis JH, Mosalaganti S. Rapid structural analysis of bacterial ribosomes in situ. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.22.586148. [PMID: 38585831 PMCID: PMC10996489 DOI: 10.1101/2024.03.22.586148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Rapid structural analysis of purified proteins and their complexes has become increasingly common thanks to key methodological advances in cryo-electron microscopy (cryo-EM) and associated data processing software packages. In contrast, analogous structural analysis in cells via cryo-electron tomography (cryo-ET) remains challenging due to critical technical bottlenecks, including low-throughput sample preparation and imaging, and laborious data processing methods. Here, we describe the development of a rapid in situ cryo-ET sample preparation and data analysis workflow that results in the routine determination of sub-nm resolution ribosomal structures. We apply this workflow to E. coli, producing a 5.8 Å structure of the 70S ribosome from cells in less than 10 days, and we expect this workflow will be widely applicable to related bacterial samples.
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Affiliation(s)
- Barrett M. Powell
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Tyler S. Brant
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, 48109
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan, 48109
| | - Joseph H. Davis
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139
- Program in Computational and Systems Biology, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Shyamal Mosalaganti
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, 48109
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan, 48109
- Department of Biophysics, University of Michigan, Ann Arbor, Michigan, 48109
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29
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Fedry J, Silva J, Vanevic M, Fronik S, Mechulam Y, Schmitt E, des Georges A, Faller WJ, Förster F. Visualization of translation reorganization upon persistent ribosome collision stress in mammalian cells. Mol Cell 2024; 84:1078-1089.e4. [PMID: 38340715 PMCID: PMC7615912 DOI: 10.1016/j.molcel.2024.01.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 11/06/2023] [Accepted: 01/18/2024] [Indexed: 02/12/2024]
Abstract
Aberrantly slow ribosomes incur collisions, a sentinel of stress that triggers quality control, signaling, and translation attenuation. Although each collision response has been studied in isolation, the net consequences of their collective actions in reshaping translation in cells is poorly understood. Here, we apply cryoelectron tomography to visualize the translation machinery in mammalian cells during persistent collision stress. We find that polysomes are compressed, with up to 30% of ribosomes in helical polysomes or collided disomes, some of which are bound to the stress effector GCN1. The native collision interface extends beyond the in vitro-characterized 40S and includes the L1 stalk and eEF2, possibly contributing to translocation inhibition. The accumulation of unresolved tRNA-bound 80S and 60S and aberrant 40S configurations identifies potentially limiting steps in collision responses. Our work provides a global view of the translation machinery in response to persistent collisions and a framework for quantitative analysis of translation dynamics in situ.
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Affiliation(s)
- Juliette Fedry
- Structural Biochemistry, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584 CG Utrecht, the Netherlands; MRC Laboratory of Molecular Biology, Cambridge, CB2 0QH, UK.
| | - Joana Silva
- Division of Oncogenomics, The Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - Mihajlo Vanevic
- Structural Biochemistry, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584 CG Utrecht, the Netherlands
| | - Stanley Fronik
- Structural Biochemistry, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584 CG Utrecht, the Netherlands
| | - Yves Mechulam
- Laboratoire de Biologie Structurale de la Cellule, BIOC, Ecole polytechnique, CNRS, Institut Polytechnique de Paris, 91128 Palaiseau Cedex, France
| | - Emmanuelle Schmitt
- Laboratoire de Biologie Structurale de la Cellule, BIOC, Ecole polytechnique, CNRS, Institut Polytechnique de Paris, 91128 Palaiseau Cedex, France
| | - Amédée des Georges
- Structural Biology Initiative, CUNY Advanced Science Research Center, City University of New York, New York, NY, USA; Department of Chemistry and Biochemistry, The City College of New York, New York, NY, USA; Ph.D. Programs in Chemistry and Biochemistry, The Graduate Center, City University of New York, New York, NY, USA
| | - William James Faller
- Division of Oncogenomics, The Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - Friedrich Förster
- Structural Biochemistry, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584 CG Utrecht, the Netherlands
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30
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Chen M. Rendering protein structures inside cells at the atomic level with Unreal Engine. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.12.08.570879. [PMID: 38496473 PMCID: PMC10942390 DOI: 10.1101/2023.12.08.570879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
While the recent development of cryogenic electron tomography (CryoET) makes it possible to identify various macromolecules inside cells and determine their structure at near-atomic resolution, it remains challenging to visualize the complex cellular environment at the atomic level. One of the main hurdles in cell visualization is to render the millions of molecules in real time computationally. Here, using a video game engine, we demonstrate the capability of rendering massive biological macromolecules at the atomic level within their native environment. To facilitate the visualization, we also provide tools that help the interactive navigation inside the cells, as well as software that converts protein structures identified using CryoET to a scene that can be explored with the game engine.
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Affiliation(s)
- Muyuan Chen
- Division of CryoEM and Bioimaging, SSRL, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, CA 94025, USA
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31
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Powell BM, Davis JH. Learning structural heterogeneity from cryo-electron sub-tomograms with tomoDRGN. Nat Methods 2024:10.1038/s41592-024-02210-z. [PMID: 38459385 DOI: 10.1038/s41592-024-02210-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 02/13/2024] [Indexed: 03/10/2024]
Abstract
Cryo-electron tomography (cryo-ET) enables observation of macromolecular complexes in their native, spatially contextualized cellular environment. Cryo-ET processing software to visualize such complexes at nanometer resolution via iterative alignment and averaging are well developed but rely upon assumptions of structural homogeneity among the complexes of interest. Recently developed tools allow for some assessment of structural diversity but have limited capacity to represent highly heterogeneous structures, including those undergoing continuous conformational changes. Here we extend the highly expressive cryoDRGN (Deep Reconstructing Generative Networks) deep learning architecture, originally created for single-particle cryo-electron microscopy analysis, to cryo-ET. Our new tool, tomoDRGN, learns a continuous low-dimensional representation of structural heterogeneity in cryo-ET datasets while also learning to reconstruct heterogeneous structural ensembles supported by the underlying data. Using simulated and experimental data, we describe and benchmark architectural choices within tomoDRGN that are uniquely necessitated and enabled by cryo-ET. We additionally illustrate tomoDRGN's efficacy in analyzing diverse datasets, using it to reveal high-level organization of human immunodeficiency virus (HIV) capsid complexes assembled in virus-like particles and to resolve extensive structural heterogeneity among ribosomes imaged in situ.
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Affiliation(s)
- Barrett M Powell
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA.
| | - Joseph H Davis
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Program in Computational and Systems Biology, Massachusetts Institute of Technology, Cambridge, MA, USA.
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32
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Mastronarde DN. Accurate, automatic determination of astigmatism and phase with Ctfplotter in IMOD. J Struct Biol 2024; 216:108057. [PMID: 38182035 PMCID: PMC10939802 DOI: 10.1016/j.jsb.2023.108057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 12/22/2023] [Accepted: 12/28/2023] [Indexed: 01/07/2024]
Abstract
Ctfplotter in the IMOD software package is a flexible program for determination of CTF parameters in tilt series images. It uses a novel approach to find astigmatism by measuring defocus in one-dimensional power spectra rotationally averaged over a series of restricted angular ranges. Comparisons with Ctffind, Gctf, and Warp show that Ctfplotter's estimated astigmatism is generally more reliable than that found by these programs that fit CTF parameters to two-dimensional power spectra, especially at higher tilt angles. In addition to that intrinsic advantage, Ctfplotter can reduce the variability in astigmatism estimates further by summing results over multiple tilt angles (typically 5), while still finding defocus for each individual image. Its fitting strategy also produces better phase estimates. The program now includes features for tuning the sampling of the power spectrum so that it is well-represented for analysis, and for determining an appropriate fitting range that can vary with tilt angle. It can thus be used automatically in a variety of situations, not just for fitting tilt series, and has been integrated into the SerialEM acquisition software for real-time determination of focus and astigmatism.
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Affiliation(s)
- David N Mastronarde
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, 347 UCB, Boulder, CO 80309, United States.
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33
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Bialy N, Alber F, Andrews B, Angelo M, Beliveau B, Bintu L, Boettiger A, Boehm U, Brown CM, Maina MB, Chambers JJ, Cimini BA, Eliceiri K, Errington R, Faklaris O, Gaudreault N, Germain RN, Goscinski W, Grunwald D, Halter M, Hanein D, Hickey JW, Lacoste J, Laude A, Lundberg E, Ma J, Malacrida L, Moore J, Nelson G, Neumann EK, Nitschke R, Onami S, Pimentel JA, Plant AL, Radtke AJ, Sabata B, Schapiro D, Schöneberg J, Spraggins JM, Sudar D, Adrien Maria Vierdag WM, Volkmann N, Wählby C, Wang SS, Yaniv Z, Strambio-De-Castillia C. Harmonizing the Generation and Pre-publication Stewardship of FAIR Image data. ARXIV 2024:arXiv:2401.13022v4. [PMID: 38351940 PMCID: PMC10862930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/19/2024]
Abstract
Together with the molecular knowledge of genes and proteins, biological images promise to significantly enhance the scientific understanding of complex cellular systems and to advance predictive and personalized therapeutic products for human health. For this potential to be realized, quality-assured image data must be shared among labs at a global scale to be compared, pooled, and reanalyzed, thus unleashing untold potential beyond the original purpose for which the data was generated. There are two broad sets of requirements to enable image data sharing in the life sciences. One set of requirements is articulated in the companion White Paper entitled "Enabling Global Image Data Sharing in the Life Sciences," which is published in parallel and addresses the need to build the cyberinfrastructure for sharing the digital array data (arXiv:2401.13023 [q-bio.OT], https://doi.org/10.48550/arXiv.2401.13023). In this White Paper, we detail a broad set of requirements, which involves collecting, managing, presenting, and propagating contextual information essential to assess the quality, understand the content, interpret the scientific implications, and reuse image data in the context of the experimental details. We start by providing an overview of the main lessons learned to date through international community activities, which have recently made considerable progress toward generating community standard practices for imaging Quality Control (QC) and metadata. We then provide a clear set of recommendations for amplifying this work. The driving goal is to address remaining challenges, and democratize access to common practices and tools for a spectrum of biomedical researchers, regardless of their expertise, access to resources, and geographical location.
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Affiliation(s)
- Nikki Bialy
- Morgridge Institute for Research, Madison, USA
| | | | | | | | | | | | | | | | | | | | | | - Beth A Cimini
- Broad Institute of MIT and Harvard, Imaging Platform, Cambridge, USA
| | - Kevin Eliceiri
- Morgridge Institute for Research, Madison, USA
- University of Wisconsin-Madison, Madison, USA
| | | | | | | | - Ronald N Germain
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, USA
| | | | | | - Michael Halter
- National Institute of Standards and Technology, Gaithersburg, USA
| | | | | | | | - Alex Laude
- Newcastle University, Newcastle upon Tyne, UK
| | - Emma Lundberg
- Stanford University, Palo Alto, USA
- SciLifeLab, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Jian Ma
- Carnegie Mellon University, Pittsburgh, USA
| | - Leonel Malacrida
- Institut Pasteur de Montevideo, & Universidad de la República, Montevideo, Uruguay
| | - Josh Moore
- German BioImaging-Gesellschaft für Mikroskopie und Bildanalyse e.V., Constance, Germany
| | - Glyn Nelson
- Newcastle University, Newcastle upon Tyne, UK
| | | | | | - Shuichi Onami
- RIKEN Center for Biosystems Dynamics Research, Kobe, Japan
| | | | - Anne L Plant
- National Institute of Standards and Technology, Gaithersburg, USA
| | - Andrea J Radtke
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, USA
| | | | | | | | | | - Damir Sudar
- Quantitative Imaging Systems LLC, Portland, USA
| | | | | | | | | | - Ziv Yaniv
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, USA
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34
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McCafferty CL, Klumpe S, Amaro RE, Kukulski W, Collinson L, Engel BD. Integrating cellular electron microscopy with multimodal data to explore biology across space and time. Cell 2024; 187:563-584. [PMID: 38306982 DOI: 10.1016/j.cell.2024.01.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 01/03/2024] [Accepted: 01/03/2024] [Indexed: 02/04/2024]
Abstract
Biology spans a continuum of length and time scales. Individual experimental methods only glimpse discrete pieces of this spectrum but can be combined to construct a more holistic view. In this Review, we detail the latest advancements in volume electron microscopy (vEM) and cryo-electron tomography (cryo-ET), which together can visualize biological complexity across scales from the organization of cells in large tissues to the molecular details inside native cellular environments. In addition, we discuss emerging methodologies for integrating three-dimensional electron microscopy (3DEM) imaging with multimodal data, including fluorescence microscopy, mass spectrometry, single-particle analysis, and AI-based structure prediction. This multifaceted approach fills gaps in the biological continuum, providing functional context, spatial organization, molecular identity, and native interactions. We conclude with a perspective on incorporating diverse data into computational simulations that further bridge and extend length scales while integrating the dimension of time.
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Affiliation(s)
| | - Sven Klumpe
- Research Group CryoEM Technology, Max-Planck-Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany.
| | - Rommie E Amaro
- Department of Molecular Biology, University of California, San Diego, La Jolla, CA 92093, USA.
| | - Wanda Kukulski
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bühlstrasse 28, 3012 Bern, Switzerland.
| | - Lucy Collinson
- Electron Microscopy Science Technology Platform, Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK.
| | - Benjamin D Engel
- Biozentrum, University of Basel, Spitalstrasse 41, 4056 Basel, Switzerland.
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35
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Gambelli L, McLaren M, Conners R, Sanders K, Gaines MC, Clark L, Gold VAM, Kattnig D, Sikora M, Hanus C, Isupov MN, Daum B. Structure of the two-component S-layer of the archaeon Sulfolobus acidocaldarius. eLife 2024; 13:e84617. [PMID: 38251732 PMCID: PMC10903991 DOI: 10.7554/elife.84617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 01/19/2024] [Indexed: 01/23/2024] Open
Abstract
Surface layers (S-layers) are resilient two-dimensional protein lattices that encapsulate many bacteria and most archaea. In archaea, S-layers usually form the only structural component of the cell wall and thus act as the final frontier between the cell and its environment. Therefore, S-layers are crucial for supporting microbial life. Notwithstanding their importance, little is known about archaeal S-layers at the atomic level. Here, we combined single-particle cryo electron microscopy, cryo electron tomography, and Alphafold2 predictions to generate an atomic model of the two-component S-layer of Sulfolobus acidocaldarius. The outer component of this S-layer (SlaA) is a flexible, highly glycosylated, and stable protein. Together with the inner and membrane-bound component (SlaB), they assemble into a porous and interwoven lattice. We hypothesise that jackknife-like conformational changes in SlaA play important roles in S-layer assembly.
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Affiliation(s)
- Lavinia Gambelli
- Living Systems Institute, University of Exeter, Exeter, United Kingdom
- Faculty of Environment, Science and Economy, University of Exeter, Exeter, United Kingdom
| | - Mathew McLaren
- Living Systems Institute, University of Exeter, Exeter, United Kingdom
- Faculty of Health and Life Sciences, University of Exeter, Exeter, United Kingdom
| | - Rebecca Conners
- Living Systems Institute, University of Exeter, Exeter, United Kingdom
- Faculty of Health and Life Sciences, University of Exeter, Exeter, United Kingdom
| | - Kelly Sanders
- Living Systems Institute, University of Exeter, Exeter, United Kingdom
- Faculty of Health and Life Sciences, University of Exeter, Exeter, United Kingdom
| | - Matthew C Gaines
- Living Systems Institute, University of Exeter, Exeter, United Kingdom
- Faculty of Health and Life Sciences, University of Exeter, Exeter, United Kingdom
| | - Lewis Clark
- Living Systems Institute, University of Exeter, Exeter, United Kingdom
- Faculty of Health and Life Sciences, University of Exeter, Exeter, United Kingdom
| | - Vicki A M Gold
- Living Systems Institute, University of Exeter, Exeter, United Kingdom
- Faculty of Health and Life Sciences, University of Exeter, Exeter, United Kingdom
| | - Daniel Kattnig
- Living Systems Institute, University of Exeter, Exeter, United Kingdom
- Faculty of Environment, Science and Economy, University of Exeter, Exeter, United Kingdom
| | - Mateusz Sikora
- Department of Theoretical Biophysics, Max Planck Institute for Biophysics, Frankfurt, Germany
- Malopolska Centre of Biotechnology, Jagiellonian University, Kraków, Poland
| | - Cyril Hanus
- Institute of Psychiatry and Neurosciences of Paris, Inserm UMR1266 - Université Paris Cité, Paris, France
- GHU Psychiatrie et Neurosciences de Paris, Paris, France
| | - Michail N Isupov
- Henry Wellcome Building for Biocatalysis, Biosciences, Faculty of Health and Life Sciences, University of Exeter, Exeter, United Kingdom
| | - Bertram Daum
- Living Systems Institute, University of Exeter, Exeter, United Kingdom
- Faculty of Health and Life Sciences, University of Exeter, Exeter, United Kingdom
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36
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Asarnow D, Becker VA, Bobe D, Dubbledam C, Johnston JD, Kopylov M, Lavoie NR, Li Q, Mattingly JM, Mendez JH, Paraan M, Turner J, Upadhye V, Walsh RM, Gupta M, Eng ET. Recent advances in infectious disease research using cryo-electron tomography. Front Mol Biosci 2024; 10:1296941. [PMID: 38288336 PMCID: PMC10822977 DOI: 10.3389/fmolb.2023.1296941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 12/07/2023] [Indexed: 01/31/2024] Open
Abstract
With the increasing spread of infectious diseases worldwide, there is an urgent need for novel strategies to combat them. Cryogenic sample electron microscopy (cryo-EM) techniques, particularly electron tomography (cryo-ET), have revolutionized the field of infectious disease research by enabling multiscale observation of biological structures in a near-native state. This review highlights the recent advances in infectious disease research using cryo-ET and discusses the potential of this structural biology technique to help discover mechanisms of infection in native environments and guiding in the right direction for future drug discovery.
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Affiliation(s)
- Daniel Asarnow
- Department of Biochemistry, University of Washington, Seattle, WA, United States
| | - Vada A. Becker
- Department of Medicinal Chemistry, University of Washington, Seattle, WA, United States
| | - Daija Bobe
- Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, United States
| | - Charlie Dubbledam
- Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, United States
| | - Jake D. Johnston
- Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, United States
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, United States
| | - Mykhailo Kopylov
- Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, United States
| | - Nathalie R. Lavoie
- Department of Molecular Biology and Microbiology, School of Medicine, Tufts University, Boston, MA, United States
| | - Qiuye Li
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, United States
| | - Jacob M. Mattingly
- Department of Chemistry, College of Arts and Sciences, Emory University, Atlanta, GA, United States
| | - Joshua H. Mendez
- Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, United States
| | - Mohammadreza Paraan
- Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, United States
| | - Jack Turner
- European Bioinformatics Institute (EMBL-EBI), Cambridge, United Kingdom
| | - Viraj Upadhye
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY, United States
| | - Richard M. Walsh
- Harvard Cryo-Electron Microscopy Center for Structural Biology and Harvard Medical School, Boston, MA, United States
| | - Meghna Gupta
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA, United States
| | - Edward T. Eng
- Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, United States
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37
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Fernández FJ, Querol-García J, Navas-Yuste S, Martino F, Vega MC. X-Ray Crystallography for Macromolecular Complexes. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2024; 3234:125-140. [PMID: 38507204 DOI: 10.1007/978-3-031-52193-5_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/22/2024]
Abstract
X-ray crystallography has for most of the last century been the standard technique to determine the high-resolution structure of biological macromolecules, including multi-subunit protein-protein and protein-nucleic acids as large as the ribosome and viruses. As such, the successful application of X-ray crystallography to many biological problems revolutionized biology and biomedicine by solving the structures of small molecules and vitamins, peptides and proteins, DNA and RNA molecules, and many complexes-affording a detailed knowledge of the structures that clarified biological and chemical mechanisms, conformational changes, interactions, catalysis and the biological processes underlying DNA replication, translation, and protein synthesis. Now reaching well into the first quarter of the twenty-first century, X-ray crystallography shares the structural biology stage with cryo-electron microscopy and other innovative structure determination methods, as relevant and central to our understanding of biological function and structure as ever. In this chapter, we provide an overview of modern X-ray crystallography and how it interfaces with other mainstream structural biology techniques, with an emphasis on macromolecular complexes.
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Affiliation(s)
| | | | - Sergio Navas-Yuste
- Centro de Investigaciones Biológicas Margarita Salas (CIB-CSIC), Madrid, Spain
| | - Fabrizio Martino
- Structural Biology Research Centre, Human Technopole, Milan, Italy
| | - M Cristina Vega
- Centro de Investigaciones Biológicas Margarita Salas (CIB-CSIC), Madrid, Spain.
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38
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Ching C, Maufront J, di Cicco A, Lévy D, Dezi M. C ool-contacts: Cryo-Electron Microscopy of Membrane Contact Sites and Their Components. CONTACT (THOUSAND OAKS (VENTURA COUNTY, CALIF.)) 2024; 7:25152564241231364. [PMID: 38410695 PMCID: PMC10895918 DOI: 10.1177/25152564241231364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 01/23/2024] [Indexed: 02/28/2024]
Abstract
Electron microscopy has played a pivotal role in elucidating the ultrastructure of membrane contact sites between cellular organelles. The advent of cryo-electron microscopy has ushered in the ability to determine atomic models of constituent proteins or protein complexes within sites of membrane contact through single particle analysis. Furthermore, it enables the visualization of the three-dimensional architecture of membrane contact sites, encompassing numerous copies of proteins, whether in vitro reconstituted or directly observed in situ using cryo-electron tomography. Nevertheless, there exists a scarcity of cryo-electron microscopy studies focused on the site of membrane contact and their constitutive proteins. This review provides an overview of the contributions made by cryo-electron microscopy to our understanding of membrane contact sites, outlines the associated limitations, and explores prospects in this field.
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Affiliation(s)
- Cyan Ching
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Laboratoire Physique des Cellules et Cancer, Paris, France
| | - Julien Maufront
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Laboratoire Physique des Cellules et Cancer, Paris, France
| | - Aurélie di Cicco
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Laboratoire Physique des Cellules et Cancer, Paris, France
| | - Daniel Lévy
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Laboratoire Physique des Cellules et Cancer, Paris, France
| | - Manuela Dezi
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Laboratoire Physique des Cellules et Cancer, Paris, France
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39
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Wan W, Khavnekar S, Wagner J. STOPGAP, an open-source package for template matching, subtomogram alignment, and classification. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.20.572665. [PMID: 38187721 PMCID: PMC10769363 DOI: 10.1101/2023.12.20.572665] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
Cryo-electron tomography (cryo-ET) enables molecular-resolution 3D imaging of complex biological specimens such as viral particles, cellular sections, and in some cases, whole cells. This enables the structural characterization of molecules in their near-native environments, without the need for purification or separation, thereby preserving biological information such as conformational states and spatial relationships between different molecular species. Subtomogram averaging is an image processing workflow that allows users to leverage cryo-ET data to identify and localize target molecules, determine high-resolution structures of repeating molecular species, and classifying different conformational states. Here we describe STOPGAP, an open-source package for subtomogram averaging designed to provide users with fine control over each of these steps. In providing detailed descriptions of the image processing algorithms that STOPGAP uses, we intend for this manuscript to also serve as a technical resource to users as well as further community-driven software development.
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Affiliation(s)
- William Wan
- Department of Biochemistry and Center for Structural Biology, Vanderbilt University, Nashville TN, USA
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40
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Schiøtz OH, Kaiser CJO, Klumpe S, Morado DR, Poege M, Schneider J, Beck F, Klebl DP, Thompson C, Plitzko JM. Serial Lift-Out: sampling the molecular anatomy of whole organisms. Nat Methods 2023:10.1038/s41592-023-02113-5. [PMID: 38110637 DOI: 10.1038/s41592-023-02113-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 10/25/2023] [Indexed: 12/20/2023]
Abstract
Cryo-focused ion beam milling of frozen-hydrated cells and subsequent cryo-electron tomography (cryo-ET) has enabled the structural elucidation of macromolecular complexes directly inside cells. Application of the technique to multicellular organisms and tissues, however, is still limited by sample preparation. While high-pressure freezing enables the vitrification of thicker samples, it prolongs subsequent preparation due to increased thinning times and the need for extraction procedures. Additionally, thinning removes large portions of the specimen, restricting the imageable volume to the thickness of the final lamella, typically <300 nm. Here we introduce Serial Lift-Out, an enhanced lift-out technique that increases throughput and obtainable contextual information by preparing multiple sections from single transfers. We apply Serial Lift-Out to Caenorhabditis elegans L1 larvae, yielding a cryo-ET dataset sampling the worm's anterior-posterior axis, and resolve its ribosome structure to 7 Å and a subregion of the 11-protofilament microtubule to 13 Å, illustrating how Serial Lift-Out enables the study of multicellular molecular anatomy.
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Affiliation(s)
- Oda Helene Schiøtz
- Research Group CryoEM Technology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Christoph J O Kaiser
- Research Group CryoEM Technology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Sven Klumpe
- Research Group CryoEM Technology, Max Planck Institute of Biochemistry, Martinsried, Germany.
| | - Dustin R Morado
- Department of Cell and Virus Structure, Max Planck Institute of Biochemistry, Martinsried, Germany
- Department for Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, Stockholm, Sweden
| | - Matthias Poege
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Jonathan Schneider
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Florian Beck
- Research Group CryoEM Technology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - David P Klebl
- Department of Cell and Virus Structure, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Christopher Thompson
- Materials and Structural Analysis, Thermo Fisher Scientific, Eindhoven, the Netherlands
| | - Jürgen M Plitzko
- Research Group CryoEM Technology, Max Planck Institute of Biochemistry, Martinsried, Germany.
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41
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Chen M, Sahoo B, Mou Z, Song X, Tsai T, Dai X. Genome organization in double-stranded DNA viruses observed by cryoET. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.15.571939. [PMID: 38168199 PMCID: PMC10760162 DOI: 10.1101/2023.12.15.571939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Double-stranded DNA (dsDNA) viruses package their genetic material into protein cages with diameters usually a few hundred times smaller than the length of their genome. Compressing the relatively stiff and highly negatively charged dsDNA into a small volume is energetically costly and mechanistically enigmatic. Multiple models of dsDNA packaging have been proposed based on various experimental evidence and simulation methods, but direct observation of any viral genome organization is lacking. Here, using cryoET and an improved data processing scheme that utilizes information from the encaging protein shell, we present 3D views of dsDNA genome inside individual viral particles at resolution that densities of neighboring DNA duplexes are readily separable. These cryoET observations reveal a "rod-and-coil" fold of the dsDNA that is conserved among herpes simplex virus type 1 (HSV-1) with a spherical capsid, bacteriophage T4 with a prolate capsid, and bacteriophage T7 with a proteinaceous core inside the capsid. Finally, inspired by the genome arrangement in partially packaged T4 particles, we propose a mechanism for the genome packaging process in dsDNA viruses.
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Affiliation(s)
- Muyuan Chen
- Division of CryoEM and Bioimaging, SSRL, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, CA 94025, USA
| | - Bibekananda Sahoo
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Zongjun Mou
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Xiyong Song
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Tiffany Tsai
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Xinghong Dai
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106, USA
- Lead contact
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42
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Markert JW, Vos SM, Farnung L. Structure of the complete Saccharomyces cerevisiae Rpd3S-nucleosome complex. Nat Commun 2023; 14:8128. [PMID: 38065958 PMCID: PMC10709384 DOI: 10.1038/s41467-023-43968-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Accepted: 11/24/2023] [Indexed: 12/18/2023] Open
Abstract
Acetylation of histones is a key post-translational modification that guides gene expression regulation. In yeast, the class I histone deacetylase containing Rpd3S complex plays a critical role in the suppression of spurious transcription by removing histone acetylation from actively transcribed genes. The S. cerevisiae Rpd3S complex has five subunits (Rpd3, Sin3, Rco1, Eaf3, and Ume1) but its subunit stoichiometry and how the complex engages nucleosomes to achieve substrate specificity remains elusive. Here we report the cryo-EM structure of the complete Rpd3S complex bound to a nucleosome. Sin3 and two copies of subunits Rco1 and Eaf3 encircle the deacetylase subunit Rpd3 and coordinate the positioning of Ume1. The Rpd3S complex binds both trimethylated H3 tails at position lysine 36 and makes multiple additional contacts with the nucleosomal DNA and the H2A-H2B acidic patch. Direct regulation via the Sin3 subunit coordinates binding of the acetylated histone substrate to achieve substrate specificity.
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Affiliation(s)
- Jonathan W Markert
- Department of Cell Biology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Seychelle M Vos
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA.
| | - Lucas Farnung
- Department of Cell Biology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA.
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43
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de la Cruz MJ, Eng ET. Scaling up cryo-EM for biology and chemistry: The journey from niche technology to mainstream method. Structure 2023; 31:1487-1498. [PMID: 37820731 PMCID: PMC10841453 DOI: 10.1016/j.str.2023.09.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Revised: 08/31/2023] [Accepted: 09/14/2023] [Indexed: 10/13/2023]
Abstract
Cryoelectron microscopy (cryo-EM) methods have made meaningful contributions in a wide variety of scientific research fields. In structural biology, cryo-EM routinely elucidates molecular structure from isolated biological macromolecular complexes or in a cellular context by harnessing the high-resolution power of the electron in order to image samples in a frozen, hydrated environment. For structural chemistry, the cryo-EM method popularly known as microcrystal electron diffraction (MicroED) has facilitated atomic structure generation of peptides and small molecules from their three-dimensional crystal forms. As cryo-EM has grown from an emerging technology, it has undergone modernization to enable multimodal transmission electron microscopy (TEM) techniques becoming more routine, reproducible, and accessible to accelerate research across multiple disciplines. We review recent advances in modern cryo-EM and assess how they are contributing to the future of the field with an eye to the past.
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Affiliation(s)
- M Jason de la Cruz
- Structural Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA.
| | - Edward T Eng
- Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY 10027, USA.
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44
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Klebl DP, Aspinall L, Muench SP. Time resolved applications for Cryo-EM; approaches, challenges and future directions. Curr Opin Struct Biol 2023; 83:102696. [PMID: 37716094 DOI: 10.1016/j.sbi.2023.102696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 06/14/2023] [Accepted: 08/14/2023] [Indexed: 09/18/2023]
Abstract
Developments within the cryo-EM field have allowed us to generate higher-resolution "static" structures and pull out different conformational states which exist at equilibrium within the sample. Moreover, to trap non-equilibrium states and determine conformations that are present after a defined period of time (typically in the ms time frame) new approaches have been developed for the application of time-resolved cryo-EM. Here we give an overview of these different approaches and the limitations and strengths of each whilst identifying some of the current challenges to achieve higher resolutions and trap states within faster time frames. Time-resolved applications may play an important role in the ever-expanding toolkit of cryo-EM and open up new possibilities in both single particle and tomographic studies.
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Affiliation(s)
- David P Klebl
- School of Biomedical Sciences, Astbury Centre for Structural Molecular Biology, University of Leeds, UK
| | - Louie Aspinall
- School of Molecular and Cellular Biology, University of Leeds, UK
| | - Stephen P Muench
- School of Biomedical Sciences, Astbury Centre for Structural Molecular Biology, University of Leeds, UK.
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45
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Fung HKH, Hayashi Y, Salo VT, Babenko A, Zagoriy I, Brunner A, Ellenberg J, Müller CW, Cuylen-Haering S, Mahamid J. Genetically encoded multimeric tags for subcellular protein localization in cryo-EM. Nat Methods 2023; 20:1900-1908. [PMID: 37932397 PMCID: PMC10703698 DOI: 10.1038/s41592-023-02053-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Accepted: 09/19/2023] [Indexed: 11/08/2023]
Abstract
Cryo-electron tomography (cryo-ET) allows for label-free high-resolution imaging of macromolecular assemblies in their native cellular context. However, the localization of macromolecules of interest in tomographic volumes can be challenging. Here we present a ligand-inducible labeling strategy for intracellular proteins based on fluorescent, 25-nm-sized, genetically encoded multimeric particles (GEMs). The particles exhibit recognizable structural signatures, enabling their automated detection in cryo-ET data by convolutional neural networks. The coupling of GEMs to green fluorescent protein-tagged macromolecules of interest is triggered by addition of a small-molecule ligand, allowing for time-controlled labeling to minimize disturbance to native protein function. We demonstrate the applicability of GEMs for subcellular-level localization of endogenous and overexpressed proteins across different organelles in human cells using cryo-correlative fluorescence and cryo-ET imaging. We describe means for quantifying labeling specificity and efficiency, and for systematic optimization for rare and abundant protein targets, with emphasis on assessing the potential effects of labeling on protein function.
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Affiliation(s)
- Herman K H Fung
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Yuki Hayashi
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Veijo T Salo
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Anastasiia Babenko
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
- University of Heidelberg, Heidelberg, Germany
| | - Ievgeniia Zagoriy
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Andreas Brunner
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- Faculty of Biosciences, Collaboration for Joint PhD Degree between EMBL and Heidelberg University, Heidelberg, Germany
| | - Jan Ellenberg
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Christoph W Müller
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Sara Cuylen-Haering
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany.
| | - Julia Mahamid
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany.
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany.
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46
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Liu HF, Zhou Y, Huang Q, Piland J, Jin W, Mandel J, Du X, Martin J, Bartesaghi A. nextPYP: a comprehensive and scalable platform for characterizing protein variability in situ using single-particle cryo-electron tomography. Nat Methods 2023; 20:1909-1919. [PMID: 37884796 PMCID: PMC10703682 DOI: 10.1038/s41592-023-02045-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 09/12/2023] [Indexed: 10/28/2023]
Abstract
Single-particle cryo-electron tomography is an emerging technique capable of determining the structure of proteins imaged within the native context of cells at molecular resolution. While high-throughput techniques for sample preparation and tilt-series acquisition are beginning to provide sufficient data to allow structural studies of proteins at physiological concentrations, the complex data analysis pipeline and the demanding storage and computational requirements pose major barriers for the development and broader adoption of this technology. Here, we present a scalable, end-to-end framework for single-particle cryo-electron tomography data analysis from on-the-fly pre-processing of tilt series to high-resolution refinement and classification, which allows efficient analysis and visualization of datasets with hundreds of tilt series and hundreds of thousands of particles. We validate our approach using in vitro and cellular datasets, demonstrating its effectiveness at achieving high-resolution and revealing conformational heterogeneity in situ. The framework is made available through an intuitive and easy-to-use computer application, nextPYP ( http://nextpyp.app ).
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Affiliation(s)
- Hsuan-Fu Liu
- Department of Biochemistry, Duke University, Durham, NC, USA
| | - Ye Zhou
- Department of Computer Science, Duke University, Durham, NC, USA
| | - Qinwen Huang
- Department of Computer Science, Duke University, Durham, NC, USA
| | - Jonathan Piland
- Department of Electrical and Computer Engineering, Duke University, Durham, NC, USA
| | - Weisheng Jin
- Department of Computer Science, Duke University, Durham, NC, USA
| | - Justin Mandel
- Department of Computer Science, Duke University, Durham, NC, USA
| | - Xiaochen Du
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Jeffrey Martin
- Department of Computer Science, Duke University, Durham, NC, USA
| | - Alberto Bartesaghi
- Department of Biochemistry, Duke University, Durham, NC, USA.
- Department of Computer Science, Duke University, Durham, NC, USA.
- Department of Electrical and Computer Engineering, Duke University, Durham, NC, USA.
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47
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Gao J, Tong M, Lee C, Gaertig J, Legal T, Bui KH. DomainFit: Identification of Protein Domains in cryo-EM maps at Intermediate Resolution using AlphaFold2-predicted Models. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.28.569001. [PMID: 38077012 PMCID: PMC10705406 DOI: 10.1101/2023.11.28.569001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/20/2023]
Abstract
Cryo-electron microscopy (cryo-EM) has revolutionized our understanding of macromolecular complexes, enabling high-resolution structure determination. With the paradigm shift to in situ structural biology recently driven by the ground-breaking development of cryo-focused ion beam milling and cryo-electron tomography, there are an increasing number of structures at sub-nanometer resolution of complexes solved directly within their cellular environment. These cellular complexes often contain unidentified proteins, related to different cellular states or processes. Identifying proteins at resolutions lower than 4 Å remains challenging because the side chains cannot be visualized reliably. Here, we present DomainFit, a program for automated domain-level protein identification from cryo-EM maps at resolutions lower than 4 Å. By fitting domains from artificial intelligence-predicted models such as AlphaFold2-predicted models into cryo-EM maps, the program performs statistical analyses and attempts to identify the proteins forming the density. Using DomainFit, we identified two microtubule inner proteins, one of them, a CCDC81 domain-containing protein, is exclusively localized in the proximal region of the doublet microtubule from the ciliate Tetrahymena thermophila. The flexibility and capability of DomainFit makes it a valuable tool for analyzing in situ structures.
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Affiliation(s)
- Jerry Gao
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, McGill University, Québec, Canada
- Centre de recherche en biologie structurale, McGill University, Montréal, Quebec, Canada
| | - Max Tong
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, McGill University, Québec, Canada
- Centre de recherche en biologie structurale, McGill University, Montréal, Quebec, Canada
| | - Chinkyu Lee
- Department of Cellular Biology, University of Georgia, Athens, GA, USA
| | - Jacek Gaertig
- Department of Cellular Biology, University of Georgia, Athens, GA, USA
| | - Thibault Legal
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, McGill University, Québec, Canada
- Centre de recherche en biologie structurale, McGill University, Montréal, Quebec, Canada
| | - Khanh Huy Bui
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, McGill University, Québec, Canada
- Centre de recherche en biologie structurale, McGill University, Montréal, Quebec, Canada
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Lucas BA, Himes BA, Grigorieff N. Baited reconstruction with 2D template matching for high-resolution structure determination in vitro and in vivo without template bias. eLife 2023; 12:RP90486. [PMID: 38010355 PMCID: PMC10681363 DOI: 10.7554/elife.90486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2023] Open
Abstract
Previously we showed that 2D template matching (2DTM) can be used to localize macromolecular complexes in images recorded by cryogenic electron microscopy (cryo-EM) with high precision, even in the presence of noise and cellular background (Lucas et al., 2021; Lucas et al., 2022). Here, we show that once localized, these particles may be averaged together to generate high-resolution 3D reconstructions. However, regions included in the template may suffer from template bias, leading to inflated resolution estimates and making the interpretation of high-resolution features unreliable. We evaluate conditions that minimize template bias while retaining the benefits of high-precision localization, and we show that molecular features not present in the template can be reconstructed at high resolution from targets found by 2DTM, extending prior work at low-resolution. Moreover, we present a quantitative metric for template bias to aid the interpretation of 3D reconstructions calculated with particles localized using high-resolution templates and fine angular sampling.
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Affiliation(s)
- Bronwyn A Lucas
- RNA Therapeutics Institute, University of Massachusetts Chan Medical SchoolWorcesterUnited States
- Department of Molecular and Cell Biology, University of California BerkeleyBerkeleyUnited States
- Center for Computational Biology, University of California BerkeleyBerkeleyUnited States
| | - Benjamin A Himes
- RNA Therapeutics Institute, University of Massachusetts Chan Medical SchoolWorcesterUnited States
- Howard Hughes Medical InstituteChevy ChaseUnited States
| | - Nikolaus Grigorieff
- RNA Therapeutics Institute, University of Massachusetts Chan Medical SchoolWorcesterUnited States
- Howard Hughes Medical InstituteChevy ChaseUnited States
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Tai L, Yin G, Huang X, Sun F, Zhu Y. In-cell structural insight into the stability of sperm microtubule doublet. Cell Discov 2023; 9:116. [PMID: 37989994 PMCID: PMC10663601 DOI: 10.1038/s41421-023-00606-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2023] [Accepted: 09/21/2023] [Indexed: 11/23/2023] Open
Abstract
The propulsion for mammalian sperm swimming is generated by flagella beating. Microtubule doublets (DMTs) along with microtubule inner proteins (MIPs) are essential structural blocks of flagella. However, the intricate molecular architecture of intact sperm DMT remains elusive. Here, by in situ cryo-electron tomography, we solved the in-cell structure of mouse sperm DMT at 4.5-7.5 Å resolutions, and built its model with 36 kinds of MIPs in 48 nm periodicity. We identified multiple copies of Tektin5 that reinforce Tektin bundle, and multiple MIPs with different periodicities that anchor the Tektin bundle to tubulin wall. This architecture contributes to a superior stability of A-tubule than B-tubule of DMT, which was revealed by structural comparison of DMTs from the intact and deformed axonemes. Our work provides an overall molecular picture of intact sperm DMT in 48 nm periodicity that is essential to understand the molecular mechanism of sperm motility as well as the related ciliopathies.
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Affiliation(s)
- Linhua Tai
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Guoliang Yin
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Xiaojun Huang
- Center for Biological Imaging, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Fei Sun
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.
- University of Chinese Academy of Sciences, Beijing, China.
- Center for Biological Imaging, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.
- Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, Guangdong, China.
| | - Yun Zhu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.
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Ochner H, Bharat TAM. Charting the molecular landscape of the cell. Structure 2023; 31:1297-1305. [PMID: 37699393 PMCID: PMC7615466 DOI: 10.1016/j.str.2023.08.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 08/15/2023] [Accepted: 08/17/2023] [Indexed: 09/14/2023]
Abstract
Biological function of macromolecules is closely tied to their cellular location, as well as to interactions with other molecules within the native environment of the cell. Therefore, to obtain detailed mechanistic insights into macromolecular functionality, one of the outstanding targets for structural biology is to produce an atomic-level understanding of the cell. One structural biology technique that has already been used to directly derive atomic models of macromolecules from cells, without any additional external information, is electron cryotomography (cryoET). In this perspective article, we discuss possible routes to chart the molecular landscape of the cell by advancing cryoET imaging as well as by embedding cryoET into correlative imaging workflows.
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Affiliation(s)
- Hannah Ochner
- Structural Studies Division, MRC Laboratory of Molecular Biology, CB2 0QH Cambridge, UK
| | - Tanmay A M Bharat
- Structural Studies Division, MRC Laboratory of Molecular Biology, CB2 0QH Cambridge, UK.
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