1
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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 PMCID: PMC11228483 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, CA94305
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA94305
- Department of Structural Biology, Stanford University, Stanford, CA94305
- Department of Photon Science, Stanford University, Stanford, CA94305
- HHMI, Stanford University, Stanford, CA94305
| | - Jiahao Liang
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA94305
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA94305
- Department of Structural Biology, Stanford University, Stanford, CA94305
- Department of Photon Science, Stanford University, Stanford, CA94305
- HHMI, Stanford University, Stanford, CA94305
| | - Axel T. Brunger
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA94305
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA94305
- Department of Structural Biology, Stanford University, Stanford, CA94305
- Department of Photon Science, Stanford University, Stanford, CA94305
- HHMI, Stanford University, Stanford, CA94305
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2
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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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3
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Ruedas R, Vuillemot R, Tubiana T, Winter JM, Pieri L, Arteni AA, Samson C, Jonic S, Mathieu M, Bressanelli S. Structure and conformational variability of the HER2-trastuzumab-pertuzumab complex. J Struct Biol 2024; 216:108095. [PMID: 38723875 DOI: 10.1016/j.jsb.2024.108095] [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: 12/02/2023] [Revised: 03/11/2024] [Accepted: 04/24/2024] [Indexed: 05/13/2024]
Abstract
Single particle analysis from cryogenic transmission electron microscopy (cryo-EM) is particularly attractive for complexes for which structure prediction remains intractable, such as antibody-antigen complexes. Here we obtain the detailed structure of a particularly difficult complex between human epidermal growth factor receptor 2 (HER2) and the antigen-binding fragments from two distinct therapeutic antibodies binding to distant parts of the flexible HER2, pertuzumab and trastuzumab (HTP). We highlight the strengths and limitations of current data processing software in dealing with various kinds of heterogeneities, particularly continuous conformational heterogeneity, and in describing the motions that can be extracted from our dataset. Our HTP structure provides a more detailed view than the one previously available for this ternary complex. This allowed us to pinpoint a previously overlooked loop in domain IV that may be involved both in binding of trastuzumab and in HER2 dimerization. This finding may contribute to explain the synergistic anticancer effect of the two antibodies. We further propose that the flexibility of the HTP complex, beyond the difficulties it causes for cryo-EM analysis, actually reflects regulation of HER2 signaling and its inhibition by therapeutic antibodies. Notably we obtain our best data with ultra-thin continuous carbon grids, showing that with current cameras their use to alleviate particle misdistribution is compatible with a protein complex of only 162 kDa. Perhaps most importantly, we provide here a dataset for such a smallish protein complex for further development of software accounting for continuous conformational heterogeneity in cryo-EM images.
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Affiliation(s)
- Rémi Ruedas
- Université Paris-Saclay, CEA, CNRS - Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France; Sanofi, Integrated Drug Discovery, 13, quai Jules Guesde 94403, Vitry-sur-Seine, France
| | - Rémi Vuillemot
- IMPMC-UMR 7590 CNRS, Sorbonne Université, Muséum National d'Histoire Naturelle, 75005, Paris, France
| | - Thibault Tubiana
- Université Paris-Saclay, CEA, CNRS - Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Jean-Marie Winter
- NanoImaging Core Facility, Centre de Ressources et Recherches Technologiques (C2RT), Institut Pasteur, 75015, Paris, France
| | - Laura Pieri
- Université Paris-Saclay, CEA, CNRS - Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Ana-Andreea Arteni
- Université Paris-Saclay, CEA, CNRS - Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Camille Samson
- Sanofi, Integrated Drug Discovery, 13, quai Jules Guesde 94403, Vitry-sur-Seine, France
| | - Slavica Jonic
- IMPMC-UMR 7590 CNRS, Sorbonne Université, Muséum National d'Histoire Naturelle, 75005, Paris, France
| | - Magali Mathieu
- Sanofi, Integrated Drug Discovery, 13, quai Jules Guesde 94403, Vitry-sur-Seine, France
| | - Stéphane Bressanelli
- Université Paris-Saclay, CEA, CNRS - Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France.
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4
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Xu D, Ando N. Miffi: Improving the accuracy of CNN-based cryo-EM micrograph filtering with fine-tuning and Fourier space information. J Struct Biol 2024; 216:108072. [PMID: 38431179 PMCID: PMC11162944 DOI: 10.1016/j.jsb.2024.108072] [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: 12/11/2023] [Revised: 02/11/2024] [Accepted: 02/25/2024] [Indexed: 03/05/2024]
Abstract
Efficient and high-accuracy filtering of cryo-electron microscopy (cryo-EM) micrographs is an emerging challenge with the growing speed of data collection and sizes of datasets. Convolutional neural networks (CNNs) are machine learning models that have been proven successful in many computer vision tasks, and have been previously applied to cryo-EM micrograph filtering. In this work, we demonstrate that two strategies, fine-tuning models from pretrained weights and including the power spectrum of micrographs as input, can greatly improve the attainable prediction accuracy of CNN models. The resulting software package, Miffi, is open-source and freely available for public use (https://github.com/ando-lab/miffi).
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Affiliation(s)
- Da Xu
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA
| | - Nozomi Ando
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA.
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5
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Maso L, Rajak E, Bang I, Koide A, Hattori T, Neel BG, Koide S. Molecular basis for antibody recognition of multiple drug-peptide/MHC complexes. Proc Natl Acad Sci U S A 2024; 121:e2319029121. [PMID: 38781214 PMCID: PMC11145297 DOI: 10.1073/pnas.2319029121] [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: 10/30/2023] [Accepted: 02/14/2024] [Indexed: 05/25/2024] Open
Abstract
The HapImmuneTM platform exploits covalent inhibitors as haptens for creating major histocompatibility complex (MHC)-presented tumor-specific neoantigens by design, combining targeted therapies with immunotherapy for the treatment of drug-resistant cancers. A HapImmune antibody, R023, recognizes multiple sotorasib-conjugated KRAS(G12C) peptides presented by different human leukocyte antigens (HLAs). This high specificity to sotorasib, coupled with broad HLA-binding capability, enables such antibodies, when reformatted as T cell engagers, to potently and selectively kill sotorasib-resistant KRAS(G12C) cancer cells expressing different HLAs upon sotorasib treatment. The loosening of HLA restriction could increase the patient population that can benefit from this therapeutic approach. To understand the molecular basis for its unconventional binding capability, we used single-particle cryogenic electron microscopy to determine the structures of R023 bound to multiple sotorasib-peptide conjugates presented by different HLAs. R023 forms a pocket for sotorasib between the VH and VL domains, binds HLAs in an unconventional, angled way, with VL making most contacts with them, and makes few contacts with the peptide moieties. This binding mode enables the antibody to accommodate different hapten-peptide conjugates and to adjust its conformation to different HLAs presenting hapten-peptides. Deep mutational scanning validated the structures and revealed distinct levels of mutation tolerance by sotorasib- and HLA-binding residues. Together, our structural information and sequence landscape analysis reveal key features for achieving MHC-restricted recognition of multiple hapten-peptide antigens, which will inform the development of next-generation therapeutic antibodies.
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Affiliation(s)
- Lorenzo Maso
- Laura and Isaac Perlmutter Cancer Center, New York University Langone Health, New York, NY10016
| | - Epsa Rajak
- Laura and Isaac Perlmutter Cancer Center, New York University Langone Health, New York, NY10016
| | - Injin Bang
- Laura and Isaac Perlmutter Cancer Center, New York University Langone Health, New York, NY10016
| | - Akiko Koide
- Laura and Isaac Perlmutter Cancer Center, New York University Langone Health, New York, NY10016
- Department of Medicine, New York University School of Medicine, New York, NY10016
| | - Takamitsu Hattori
- Laura and Isaac Perlmutter Cancer Center, New York University Langone Health, New York, NY10016
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY10016
| | - Benjamin G. Neel
- Laura and Isaac Perlmutter Cancer Center, New York University Langone Health, New York, NY10016
- Department of Medicine, New York University School of Medicine, New York, NY10016
| | - Shohei Koide
- Laura and Isaac Perlmutter Cancer Center, New York University Langone Health, New York, NY10016
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY10016
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6
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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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7
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de Sautu M, Herrmann T, Scanavachi G, Jenni S, Harrison SC. The rotavirus VP5*/VP8* conformational transition permeabilizes membranes to Ca2. PLoS Pathog 2024; 20:e1011750. [PMID: 38574119 PMCID: PMC11020617 DOI: 10.1371/journal.ppat.1011750] [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: 10/16/2023] [Revised: 04/16/2024] [Accepted: 03/04/2024] [Indexed: 04/06/2024] Open
Abstract
Rotaviruses infect cells by delivering into the cytosol a transcriptionally active inner capsid particle (a "double-layer particle": DLP). Delivery is the function of a third, outer layer, which drives uptake from the cell surface into small vesicles from which the DLPs escape. In published work, we followed stages of rhesus rotavirus (RRV) entry by live-cell imaging and correlated them with structures from cryogenic electron microscopy and tomography (cryo-EM and cryo-ET). The virus appears to wrap itself in membrane, leading to complete engulfment and loss of Ca2+ from the vesicle produced by the wrapping. One of the outer-layer proteins, VP7, is a Ca2+-stabilized trimer; loss of Ca2+ releases both VP7 and the other outer-layer protein, VP4, from the particle. VP4, activated by cleavage into VP8* and VP5*, is a trimer that undergoes a large-scale conformational rearrangement, reminiscent of the transition that viral fusion proteins undergo to penetrate a membrane. The rearrangement of VP5* thrusts a 250-residue, C-terminal segment of each of the three subunits outward, while allowing the protein to remain attached to the virus particle and to the cell being infected. We proposed that this segment inserts into the membrane of the target cell, enabling Ca2+ to cross. In the work reported here, we show the validity of key aspects of this proposed sequence. By cryo-EM studies of liposome-attached virions ("triple-layer particles": TLPs) and single-particle fluorescence imaging of liposome-attached TLPs, we confirm insertion of the VP4 C-terminal segment into the membrane and ensuing generation of a Ca2+ "leak". The results allow us to formulate a molecular description of early events in entry. We also discuss our observations in the context of other work on double-strand RNA virus entry.
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Affiliation(s)
- Marilina de Sautu
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, United States of America
- Laboratory of Molecular Medicine, Boston Children’s Hospital, Boston, Massachusetts, United States of America
| | - Tobias Herrmann
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Gustavo Scanavachi
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts, United States of America
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Boston, Massachusetts, United States of America
| | - Simon Jenni
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Stephen C. Harrison
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, United States of America
- Laboratory of Molecular Medicine, Boston Children’s Hospital, Boston, Massachusetts, United States of America
- Howard Hughes Medical Institute, Harvard Medical School, Boston, Massachusetts, United States of America
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8
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Xu D, Ando N. Miffi: Improving the accuracy of CNN-based cryo-EM micrograph filtering with fine-tuning and Fourier space information. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.12.08.570849. [PMID: 38405773 PMCID: PMC10888874 DOI: 10.1101/2023.12.08.570849] [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: 02/27/2024]
Abstract
Efficient and high-accuracy filtering of cryo-electron microscopy (cryo-EM) micrographs is an emerging challenge with the growing speed of data collection and sizes of datasets. Convolutional neural networks (CNNs) are machine learning models that have been proven successful in many computer vision tasks, and have been previously applied to cryo-EM micrograph filtering. In this work, we demonstrate that two strategies, fine-tuning models from pretrained weights and including the power spectrum of micrographs as input, can greatly improve the attainable prediction accuracy of CNN models. The resulting software package, Miffi, is open-source and freely available for public use (https://github.com/ando-lab/miffi).
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Affiliation(s)
- Da Xu
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14850, USA
| | - Nozomi Ando
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14850, USA
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9
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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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10
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Xu J, Gao X, Zheng L, Jia X, Xu K, Ma Y, Wei X, Liu N, Peng H, Wang HW. Graphene sandwich-based biological specimen preparation for cryo-EM analysis. Proc Natl Acad Sci U S A 2024; 121:e2309384121. [PMID: 38252835 PMCID: PMC10835136 DOI: 10.1073/pnas.2309384121] [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: 06/11/2023] [Accepted: 12/20/2023] [Indexed: 01/24/2024] Open
Abstract
High-quality specimen preparation plays a crucial role in cryo-electron microscopy (cryo-EM) structural analysis. In this study, we have developed a reliable and convenient technique called the graphene sandwich method for preparing cryo-EM specimens. This method involves using two layers of graphene films that enclose macromolecules on both sides, allowing for an appropriate ice thickness for cryo-EM analysis. The graphene sandwich helps to mitigate beam-induced charging effect and reduce particle motion compared to specimens prepared using the traditional method with graphene support on only one side, therefore improving the cryo-EM data quality. These advancements may open new opportunities to expand the use of graphene in the field of biological electron microscopy.
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Affiliation(s)
- Jie Xu
- Ministry of Education Key Laboratory of Protein Sciences, Beijing Frontier Research Center for Biological Structure, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing100084, China
- Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing100084, China
| | - Xiaoyin Gao
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing100871, China
| | - Liming Zheng
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing100871, China
| | - Xia Jia
- Ministry of Education Key Laboratory of Protein Sciences, Beijing Frontier Research Center for Biological Structure, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing100084, China
- Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing100084, China
| | - Kui Xu
- Ministry of Education Key Laboratory of Protein Sciences, Beijing Frontier Research Center for Biological Structure, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing100084, China
- Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing100084, China
| | - Yuwei Ma
- State Key Laboratory for Turbulence and Complex System, Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing100871, China
| | - Xiaoding Wei
- State Key Laboratory for Turbulence and Complex System, Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing100871, China
| | - Nan Liu
- Ministry of Education Key Laboratory of Protein Sciences, Beijing Frontier Research Center for Biological Structure, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing100084, China
| | - Hailin Peng
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing100871, China
- Beijing Graphene Institute, Beijing100095, China
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing100871, China
| | - Hong-Wei Wang
- Ministry of Education Key Laboratory of Protein Sciences, Beijing Frontier Research Center for Biological Structure, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing100084, China
- Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing100084, China
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11
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Aiyer S, Baldwin PR, Tan SM, Shan Z, Oh J, Mehrani A, Bowman ME, Louie G, Passos DO, Đorđević-Marquardt S, Mietzsch M, Hull JA, Hoshika S, Barad BA, Grotjahn DA, McKenna R, Agbandje-McKenna M, Benner SA, Noel JAP, Wang D, Tan YZ, Lyumkis D. Overcoming resolution attenuation during tilted cryo-EM data collection. Nat Commun 2024; 15:389. [PMID: 38195598 PMCID: PMC10776679 DOI: 10.1038/s41467-023-44555-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 12/15/2023] [Indexed: 01/11/2024] Open
Abstract
Structural biology efforts using cryogenic electron microscopy are frequently stifled by specimens adopting "preferred orientations" on grids, leading to anisotropic map resolution and impeding structure determination. Tilting the specimen stage during data collection is a generalizable solution but has historically led to substantial resolution attenuation. Here, we develop updated data collection and image processing workflows and demonstrate, using multiple specimens, that resolution attenuation is negligible or significantly reduced across tilt angles. Reconstructions with and without the stage tilted as high as 60° are virtually indistinguishable. These strategies allowed the reconstruction to 3 Å resolution of a bacterial RNA polymerase with preferred orientation, containing an unnatural nucleotide for studying novel base pair recognition. Furthermore, we present a quantitative framework that allows cryo-EM practitioners to define an optimal tilt angle during data acquisition. These results reinforce the utility of employing stage tilt for data collection and provide quantitative metrics to obtain isotropic maps.
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Affiliation(s)
- Sriram Aiyer
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, CA, 92037, USA
| | - Philip R Baldwin
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, CA, 92037, USA
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Shi Min Tan
- Department of Biological Sciences, National University of Singapore, 16 Science Drive 4, Singapore, 117558, Singapore
| | - Zelin Shan
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, CA, 92037, USA
| | - Juntaek Oh
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, 92093, USA
- College of Pharmacy, Kyung Hee University, Seoul, 02247, Republic of Korea
| | - Atousa Mehrani
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, CA, 92037, USA
| | - Marianne E Bowman
- Jack H. Skirball Center for Chemical Biology and Proteomics, The Salk Institute for Biological Studies, La Jolla, CA, 92037, USA
| | - Gordon Louie
- Jack H. Skirball Center for Chemical Biology and Proteomics, The Salk Institute for Biological Studies, La Jolla, CA, 92037, USA
| | - Dario Oliveira Passos
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, CA, 92037, USA
| | | | - Mario Mietzsch
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, FL, 32610, USA
| | - Joshua A Hull
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, FL, 32610, USA
| | - Shuichi Hoshika
- Foundation for Applied Molecular Evolution, 13709 Progress Blvd Box 7, Alachua, FL, 32615, USA
| | - Benjamin A Barad
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Danielle A Grotjahn
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Robert McKenna
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, FL, 32610, USA
| | - Mavis Agbandje-McKenna
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, FL, 32610, USA
| | - Steven A Benner
- Foundation for Applied Molecular Evolution, 13709 Progress Blvd Box 7, Alachua, FL, 32615, USA
| | - Joseph A P Noel
- Jack H. Skirball Center for Chemical Biology and Proteomics, The Salk Institute for Biological Studies, La Jolla, CA, 92037, USA
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA, 92093, USA
| | - Dong Wang
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, 92093, USA
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA, 92093, USA
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Yong Zi Tan
- Department of Biological Sciences, National University of Singapore, 16 Science Drive 4, Singapore, 117558, Singapore.
- Disease Intervention Technology Laboratory (DITL), Agency for Science, Technology and Research (A*STAR), 8A Biomedical Grove, Singapore, 138648, Singapore.
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), 61 Biopolis Drive, Proteos, Singapore, 138673, Republic of Singapore.
| | - Dmitry Lyumkis
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, CA, 92037, USA.
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA.
- Graduate School of Biological Sciences, Section of Molecular Biology, University of California San Diego, La Jolla, CA, 92093, USA.
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12
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Mendez JH, Chua EYD, Paraan M, Potter CS, Carragher B. Automated pipelines for rapid evaluation during cryoEM data acquisition. Curr Opin Struct Biol 2023; 83:102729. [PMID: 37988815 DOI: 10.1016/j.sbi.2023.102729] [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: 01/24/2023] [Revised: 10/14/2023] [Accepted: 10/16/2023] [Indexed: 11/23/2023]
Abstract
Cryo-electron microscopy (cryoEM) has become a popular method for determining high-resolution structures of biomolecules. However, data processing can be time-consuming, particularly for new researchers entering the field. To improve data quality and increase data collection efficiency, several software packages have been developed for on-the-fly data processing with various degrees of automation. These software packages allow researchers to perform tasks such as motion correction, CTF estimation, 2D classification, and 3D reconstruction in real-time, with minimal human input. On-the-fly data processing can not only improve data collection efficiency but also increase the productivity of instrumentation in high demand. However, the various software packages available differ in their performance, computational requirements, and levels of automation. In this review, we describe the minimal metrics used to assess data quality during data collection, outline the features of an ideal on-the-fly data processing software systems, and provide results from using three of these systems.
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Affiliation(s)
- Joshua H Mendez
- Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, USA
| | - Eugene Y D Chua
- Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, USA
| | - Mohammadreza Paraan
- Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, USA
| | - Clinton S Potter
- Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, USA; Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Bridget Carragher
- Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, USA; Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA.
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13
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Yang Q, Wu C, Zhu D, Li J, Cheng J, Zhang X. The reduction of FIB damage on cryo-lamella by lowering energy of ion beam revealed by a quantitative analysis. Structure 2023; 31:1275-1281.e4. [PMID: 37527655 DOI: 10.1016/j.str.2023.07.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 06/08/2023] [Accepted: 07/05/2023] [Indexed: 08/03/2023]
Abstract
Focused ion beam (FIB) is widely used for thinning frozen cells to produce lamellae for cryo-electron microscopy imaging and for protein structures study in vivo. However, FIB damages the lamellae and a quantitative experimental analysis of the damage is lacking. We used a 30-keV gallium FIB to prepare lamellae of a highly concentrated icosahedral virus sample. The viruses were grouped according to their distance from the surface of lamellae and reconstructed. Damage to the approximately 20-nm-thick outermost lamella surface was similar to that from exposure to 16 e-/Å2 in a 300-kV cryo-electron microscope at high-resolution range. The damage was negligible at a depth beyond 50 nm, which was reduced to 30 nm if 8-keV Ga+ was used during polishing. We designed extra steps in the reconstruction refinement to maximize undamaged signals and increase the resolution. The results demonstrated that low-energy beam polishing was essential for high-quality thinner lamellae.
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Affiliation(s)
- Qi Yang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences (CAS), Beijing 100101, P.R. China; University of Chinese Academy of Sciences, Beijing 100049, P.R. China
| | - Chunling Wu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences (CAS), Beijing 100101, P.R. China
| | - Dongjie Zhu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences (CAS), Beijing 100101, P.R. China
| | - Junxi Li
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences (CAS), Beijing 100101, P.R. China; University of Chinese Academy of Sciences, Beijing 100049, P.R. China
| | - Jing Cheng
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences (CAS), Beijing 100101, P.R. China
| | - Xinzheng Zhang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences (CAS), Beijing 100101, P.R. China.
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14
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Skoupý R, Boltje DB, Slouf M, Mrázová K, Láznička T, Taisne CM, Krzyžánek V, Hoogenboom JP, Jakobi AJ. Robust Local Thickness Estimation of Sub-Micrometer Specimen by 4D-STEM. SMALL METHODS 2023; 7:e2300258. [PMID: 37248805 DOI: 10.1002/smtd.202300258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 04/21/2023] [Indexed: 05/31/2023]
Abstract
A quantitative four-dimensional scanning transmission electron microscopy (4D-STEM) imaging technique (q4STEM) for local thickness estimation across amorphous specimen such as obtained by focused ion beam (FIB)-milling of lamellae for (cryo-)TEM analysis is presented. This study is based on measuring spatially resolved diffraction patterns to obtain the angular distribution of electron scattering, or the ratio of integrated virtual dark and bright field STEM signals, and their quantitative evaluation using Monte Carlo simulations. The method is independent of signal intensity calibrations and only requires knowledge of the detector geometry, which is invariant for a given instrument. This study demonstrates that the method yields robust thickness estimates for sub-micrometer amorphous specimen using both direct detection and light conversion 2D-STEM detectors in a coincident FIB-SEM and a conventional SEM. Due to its facile implementation and minimal dose reauirements, it is anticipated that this method will find applications for in situ thickness monitoring during lamella fabrication of beam-sensitive materials.
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Affiliation(s)
- Radim Skoupý
- Institute of Scientific Instruments, Czech Academy of Sciences, Brno, 61264, CZ
- Department of Bionanoscience, Delft University of Technology, Delft, 2628 CD, NL
- Kavli Institute of Nanoscience, Delft University of Technology, Delft, 2628 CJ, NL
- Department of Imaging Physics, Delft University of Technology, Delft, 2628 CJ, NL
| | - Daan B Boltje
- Department of Imaging Physics, Delft University of Technology, Delft, 2628 CJ, NL
| | - Miroslav Slouf
- Institute of Macromolecular Chemistry, Czech Academy of Sciences, Prague, 162 00, CZ
| | - Kateřina Mrázová
- Institute of Scientific Instruments, Czech Academy of Sciences, Brno, 61264, CZ
| | - Tomáš Láznička
- Institute of Scientific Instruments, Czech Academy of Sciences, Brno, 61264, CZ
| | - Clémence M Taisne
- Department of Bionanoscience, Delft University of Technology, Delft, 2628 CD, NL
| | - Vladislav Krzyžánek
- Institute of Scientific Instruments, Czech Academy of Sciences, Brno, 61264, CZ
| | - Jacob P Hoogenboom
- Department of Imaging Physics, Delft University of Technology, Delft, 2628 CJ, NL
| | - Arjen J Jakobi
- Department of Bionanoscience, Delft University of Technology, Delft, 2628 CD, NL
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15
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Wu Y, Qin C, Du W, Guo Z, Chen L, Guo Q. A practical multicellular sample preparation pipeline broadens the application of in situ cryo-electron tomography. J Struct Biol 2023; 215:107971. [PMID: 37201639 DOI: 10.1016/j.jsb.2023.107971] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 04/28/2023] [Accepted: 05/11/2023] [Indexed: 05/20/2023]
Abstract
The structural studies of macromolecules in their physiological context, particularly in tissue, is constrained by the bottleneck of sample preparation. In this study, we present a practical pipeline for preparing multicellular samples for cryo-electron tomography. The pipeline comprises sample isolation, vitrification, and lift-out-based lamella preparation using commercially available instruments. We demonstrate the efficacy of our pipeline by visualizing pancreatic β cells from mouse islets at the molecular level. This pipeline enables the determination of the properties of insulin crystals in situ for the first time, using unperturbed samples.
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Affiliation(s)
- Yichun Wu
- State Key Laboratory of Protein and Plant Gene Research, Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, School of Life Sciences, Peking University, Beijing 100871, China
| | - Changdong Qin
- School of Life Sciences, Peking University, Beijing 100871, China
| | - Wenjing Du
- State Key Laboratory of Protein and Plant Gene Research, Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, School of Life Sciences, Peking University, Beijing 100871, China; Changping Laboratory, Beijing 102206, China
| | - Zhenxi Guo
- School of Life Sciences, Peking University, Beijing 100871, China; Changping Laboratory, Beijing 102206, China
| | - Liangyi Chen
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Center for Life Sciences, College of Future Technology, Peking University, Beijing 100871, China
| | - Qiang Guo
- State Key Laboratory of Protein and Plant Gene Research, Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, School of Life Sciences, Peking University, Beijing 100871, China; Changping Laboratory, Beijing 102206, China.
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16
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Han BG, Avila-Sakar A, Remis J, Glaeser RM. Challenges in making ideal cryo-EM samples. Curr Opin Struct Biol 2023; 81:102646. [PMID: 37392555 DOI: 10.1016/j.sbi.2023.102646] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 06/02/2023] [Accepted: 06/02/2023] [Indexed: 07/03/2023]
Abstract
Recognizing that interaction with the air-water interface (AWI) is a major challenge for cryo-EM, we first review current approaches designed to avoid it. Of these, immobilizing particles on affinity grids is arguably the most promising. In addition, we review efforts to gain more reliable control of the sample thicknesses, not the least important reason being to prevent immobilized particles from coming in contact with the AWI of the remaining buffer. It is emphasized that avoiding such a contact is as important for cryo-ET as for single-particle cryo-EM. Finally, looking to the future, it is proposed that immobilized samples might be used to perform time-resolved biochemical experiments directly on EM grids rather than just in test tubes or cuvettes.
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Affiliation(s)
- Bong-Gyoon Han
- Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720, USA
| | - Agustin Avila-Sakar
- Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720, USA
| | - Jonathan Remis
- Department of Physics, University of California, Berkeley, CA 94720, USA
| | - Robert M Glaeser
- Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720, USA.
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17
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Ishemgulova A, Wang J, Neselu K, Maruthi K, Zimanyi C, Aragon M, Kopylov E, Mendez J, Dubbeldam C, Eng ET. Microscope Operations at the National Center for CryoEM Access and Training (NCCAT). MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2023; 29:1041. [PMID: 37613267 DOI: 10.1093/micmic/ozad067.532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Affiliation(s)
- Aygul Ishemgulova
- National Center for CryoEM Access and Training, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NYUnited States
| | - Jing Wang
- National Center for CryoEM Access and Training, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NYUnited States
| | - Kasahun Neselu
- National Center for CryoEM Access and Training, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NYUnited States
| | - Kashyap Maruthi
- National Center for CryoEM Access and Training, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NYUnited States
| | - Christina Zimanyi
- National Center for CryoEM Access and Training, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NYUnited States
| | - Mahira Aragon
- National Center for CryoEM Access and Training, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NYUnited States
| | - Elina Kopylov
- National Center for CryoEM Access and Training, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NYUnited States
| | - Joshua Mendez
- National Center for CryoEM Access and Training, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NYUnited States
| | - Charlie Dubbeldam
- National Center for CryoEM Access and Training, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NYUnited States
| | - Edward T Eng
- National Center for CryoEM Access and Training, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NYUnited States
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18
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Aiyer S, Baldwin PR, Tan SM, Shan Z, Oh J, Mehrani A, Bowman ME, Louie G, Passos DO, Đorđević-Marquardt S, Mietzsch M, Hull JA, Hoshika S, Barad BA, Grotjahn DA, McKenna R, Agbandje-McKenna M, Benner SA, Noel JAP, Wang D, Tan YZ, Lyumkis D. Overcoming Resolution Attenuation During Tilted Cryo-EM Data Collection. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.14.548955. [PMID: 37503021 PMCID: PMC10369999 DOI: 10.1101/2023.07.14.548955] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Structural biology efforts using cryogenic electron microscopy are frequently stifled by specimens adopting "preferred orientations" on grids, leading to anisotropic map resolution and impeding structure determination. Tilting the specimen stage during data collection is a generalizable solution but has historically led to substantial resolution attenuation. Here, we develop updated data collection and image processing workflows and demonstrate, using multiple specimens, that resolution attenuation is negligible or significantly reduced across tilt angles. Reconstructions with and without the stage tilted as high as 60° are virtually indistinguishable. These strategies allowed the reconstruction to 3 Å resolution of a bacterial RNA polymerase with preferred orientation. Furthermore, we present a quantitative framework that allows cryo-EM practitioners to define an optimal tilt angle for dataset acquisition. These data reinforce the utility of employing stage tilt for data collection and provide quantitative metrics to obtain isotropic maps.
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19
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Michon B, López-Sánchez U, Degrouard J, Nury H, Leforestier A, Rio E, Salonen A, Zoonens M. Role of surfactants in electron cryo-microscopy film preparation. Biophys J 2023; 122:1846-1857. [PMID: 37077048 PMCID: PMC10209149 DOI: 10.1016/j.bpj.2023.04.016] [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: 09/30/2022] [Revised: 01/01/2023] [Accepted: 04/13/2023] [Indexed: 04/21/2023] Open
Abstract
Single-particle electron cryo-microscopy (cryo-EM) has become an effective and straightforward approach to determine the structure of membrane proteins. However, obtaining cryo-EM grids of sufficient quality for high-resolution structural analysis remains a major bottleneck. One of the difficulties arises from the presence of detergents, which often leads to a lack of control of the ice thickness. Amphipathic polymers such as amphipols (APols) are detergent substitutes, which have proven to be valuable tools for cryo-EM studies. In this work, we investigate the physico-chemical behavior of APol- and detergent-containing solutions and show a correlation with the properties of vitreous thin films in cryo-EM grids. This study provides new insight on the potential of APols, allowing a better control of ice thickness while limiting protein adsorption at the air-water interface, as shown with the full-length mouse serotonin 5-HT3A receptor whose structure has been solved in APol. These findings may speed up the process of grid optimization to obtain high-resolution structures of membrane proteins.
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Affiliation(s)
- Baptiste Michon
- Université Paris Cité, Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, CNRS, UMR 7099, Paris, France; Institut de Biologie Physico-Chimique, Fondation Edmond de Rothschild pour le développement de la recherche scientifique, Paris, France
| | | | - Jéril Degrouard
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, Orsay, France
| | - Hugues Nury
- University Grenoble Alpes, CNRS, CEA, IBS, Grenoble, France
| | - Amélie Leforestier
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, Orsay, France.
| | - Emmanuelle Rio
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, Orsay, France
| | - Anniina Salonen
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, Orsay, France
| | - Manuela Zoonens
- Université Paris Cité, Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, CNRS, UMR 7099, Paris, France; Institut de Biologie Physico-Chimique, Fondation Edmond de Rothschild pour le développement de la recherche scientifique, Paris, France.
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20
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Abstract
Recent advances in cryo-electron microscopy have marked only the beginning of the potential of this technique. To bring structure into cell biology, the modality of cryo-electron tomography has fast developed into a bona fide in situ structural biology technique where structures are determined in their native environment, the cell. Nearly every step of the cryo-focused ion beam-assisted electron tomography (cryo-FIB-ET) workflow has been improved upon in the past decade, since the first windows were carved into cells, unveiling macromolecular networks in near-native conditions. By bridging structural and cell biology, cryo-FIB-ET is advancing our understanding of structure-function relationships in their native environment and becoming a tool for discovering new biology.
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Affiliation(s)
- Lindsey N Young
- Department of Molecular Biology, University of California, San Diego, La Jolla, California, USA;
| | - Elizabeth Villa
- Department of Molecular Biology, University of California, San Diego, La Jolla, California, USA;
- Howard Hughes Medical Institute, University of California, San Diego, La Jolla, California, USA
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21
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Weaver JW, Proshkin S, Duan W, Epshtein V, Gowder M, Bharati BK, Afanaseva E, Mironov A, Serganov A, Nudler E. Control of transcription elongation and DNA repair by alarmone ppGpp. Nat Struct Mol Biol 2023; 30:600-607. [PMID: 36997761 PMCID: PMC10191844 DOI: 10.1038/s41594-023-00948-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 02/27/2023] [Indexed: 04/01/2023]
Abstract
Second messenger (p)ppGpp (collectively guanosine tetraphosphate and guanosine pentaphosphate) mediates bacterial adaptation to nutritional stress by modulating transcription initiation. More recently, ppGpp has been implicated in coupling transcription and DNA repair; however, the mechanism of ppGpp engagement remained elusive. Here we present structural, biochemical and genetic evidence that ppGpp controls Escherichia coli RNA polymerase (RNAP) during elongation via a specific site that is nonfunctional during initiation. Structure-guided mutagenesis renders the elongation (but not initiation) complex unresponsive to ppGpp and increases bacterial sensitivity to genotoxic agents and ultraviolet radiation. Thus, ppGpp binds RNAP at sites with distinct functions in initiation and elongation, with the latter being important for promoting DNA repair. Our data provide insights on the molecular mechanism of ppGpp-mediated adaptation during stress, and further highlight the intricate relationships between genome stability, stress responses and transcription.
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Affiliation(s)
- Jacob W Weaver
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY, USA
| | - Sergey Proshkin
- Engelhardt Institute of Molecular Biology, Russian Academy of Science, Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Moscow, Russia
| | - Wenqian Duan
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY, USA
| | - Vitaly Epshtein
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY, USA
| | - Manjunath Gowder
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY, USA
- Howard Hughes Medical Institute, New York University School of Medicine, New York, NY, USA
| | - Binod K Bharati
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY, USA
- Howard Hughes Medical Institute, New York University School of Medicine, New York, NY, USA
| | - Elena Afanaseva
- Engelhardt Institute of Molecular Biology, Russian Academy of Science, Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Moscow, Russia
| | - Alexander Mironov
- Engelhardt Institute of Molecular Biology, Russian Academy of Science, Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Moscow, Russia
| | - Alexander Serganov
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY, USA.
| | - Evgeny Nudler
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY, USA.
- Howard Hughes Medical Institute, New York University School of Medicine, New York, NY, USA.
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22
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Ahn E, Kim B, Park S, Erwin AL, Sung SH, Hovden R, Mosalaganti S, Cho US. Batch Production of High-Quality Graphene Grids for Cryo-EM: Cryo-EM Structure of Methylococcus capsulatus Soluble Methane Monooxygenase Hydroxylase. ACS NANO 2023; 17:6011-6022. [PMID: 36926824 PMCID: PMC10062032 DOI: 10.1021/acsnano.3c00463] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 03/13/2023] [Indexed: 06/18/2023]
Abstract
Cryogenic electron microscopy (cryo-EM) has become a widely used tool for determining the protein structure. Despite recent technical advances, sample preparation remains a major bottleneck for several reasons, including protein denaturation at the air-water interface, the presence of preferred orientations, nonuniform ice layers, etc. Graphene, a two-dimensional allotrope of carbon consisting of a single atomic layer, has recently gained attention as a near-ideal support film for cryo-EM that can overcome these challenges because of its superior properties, including mechanical strength and electrical conductivity. Here, we introduce a reliable, easily implemented, and reproducible method to produce 36 graphene-coated grids within 1.5 days. To demonstrate their practical application, we determined the cryo-EM structure of Methylococcus capsulatus soluble methane monooxygenase hydroxylase (sMMOH) at resolutions of 2.9 and 2.5 Å using Quantifoil and graphene-coated grids, respectively. We found that the graphene-coated grid has several advantages, including a smaller amount of protein required and avoiding protein denaturation at the air-water interface. By comparing the cryo-EM structure of sMMOH with its crystal structure, we identified subtle yet significant geometrical changes at the nonheme diiron center, which may better indicate the active site configuration of sMMOH in the resting/oxidized state.
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Affiliation(s)
- Eungjin Ahn
- Department
of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Byungchul Kim
- Department
of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Soyoung Park
- Department
of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department
of Fine Chemistry, Seoul National University
of Science and Technology, Seoul 139-743, Korea
| | - Amanda L. Erwin
- Department
of Cell and Developmental Biology, University
of Michigan, Ann Arbor, Michigan 48109, United
States
- Life
Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Suk Hyun Sung
- Department
of Materials Science and Engineering, University
of Michigan, Ann Arbor, Michigan 48105, United
States
| | - Robert Hovden
- Department
of Materials Science and Engineering, University
of Michigan, Ann Arbor, Michigan 48105, United
States
- Applied
Physics Program, University of Michigan, Ann Arbor, Michigan 48105, United States
| | - Shyamal Mosalaganti
- Department
of Cell and Developmental Biology, University
of Michigan, Ann Arbor, Michigan 48109, United
States
- Life
Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Uhn-Soo Cho
- Department
of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
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23
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Aluru NR, Aydin F, Bazant MZ, Blankschtein D, Brozena AH, de Souza JP, Elimelech M, Faucher S, Fourkas JT, Koman VB, Kuehne M, Kulik HJ, Li HK, Li Y, Li Z, Majumdar A, Martis J, Misra RP, Noy A, Pham TA, Qu H, Rayabharam A, Reed MA, Ritt CL, Schwegler E, Siwy Z, Strano MS, Wang Y, Yao YC, Zhan C, Zhang Z. Fluids and Electrolytes under Confinement in Single-Digit Nanopores. Chem Rev 2023; 123:2737-2831. [PMID: 36898130 PMCID: PMC10037271 DOI: 10.1021/acs.chemrev.2c00155] [Citation(s) in RCA: 28] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/12/2023]
Abstract
Confined fluids and electrolyte solutions in nanopores exhibit rich and surprising physics and chemistry that impact the mass transport and energy efficiency in many important natural systems and industrial applications. Existing theories often fail to predict the exotic effects observed in the narrowest of such pores, called single-digit nanopores (SDNs), which have diameters or conduit widths of less than 10 nm, and have only recently become accessible for experimental measurements. What SDNs reveal has been surprising, including a rapidly increasing number of examples such as extraordinarily fast water transport, distorted fluid-phase boundaries, strong ion-correlation and quantum effects, and dielectric anomalies that are not observed in larger pores. Exploiting these effects presents myriad opportunities in both basic and applied research that stand to impact a host of new technologies at the water-energy nexus, from new membranes for precise separations and water purification to new gas permeable materials for water electrolyzers and energy-storage devices. SDNs also present unique opportunities to achieve ultrasensitive and selective chemical sensing at the single-ion and single-molecule limit. In this review article, we summarize the progress on nanofluidics of SDNs, with a focus on the confinement effects that arise in these extremely narrow nanopores. The recent development of precision model systems, transformative experimental tools, and multiscale theories that have played enabling roles in advancing this frontier are reviewed. We also identify new knowledge gaps in our understanding of nanofluidic transport and provide an outlook for the future challenges and opportunities at this rapidly advancing frontier.
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Affiliation(s)
- Narayana R Aluru
- Oden Institute for Computational Engineering and Sciences, Walker Department of Mechanical Engineering, The University of Texas at Austin, Austin, 78712TexasUnited States
| | - Fikret Aydin
- Materials Science Division, Physical and Life Science Directorate, Lawrence Livermore National Laboratory, Livermore, California94550, United States
| | - Martin Z Bazant
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts02139, United States
- Department of Mathematics, Massachusetts Institute of Technology, Cambridge, Massachusetts02139, United States
| | - Daniel Blankschtein
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts02139, United States
| | - Alexandra H Brozena
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland20742, United States
| | - J Pedro de Souza
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts02139, United States
| | - Menachem Elimelech
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut06520-8286, United States
| | - Samuel Faucher
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts02139, United States
| | - John T Fourkas
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland20742, United States
- Institute for Physical Science and Technology, University of Maryland, College Park, Maryland20742, United States
- Maryland NanoCenter, University of Maryland, College Park, Maryland20742, United States
| | - Volodymyr B Koman
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts02139, United States
| | - Matthias Kuehne
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts02139, United States
| | - Heather J Kulik
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts02139, United States
| | - Hao-Kun Li
- Department of Mechanical Engineering, Stanford University, Stanford, California94305, United States
| | - Yuhao Li
- Materials Science Division, Physical and Life Science Directorate, Lawrence Livermore National Laboratory, Livermore, California94550, United States
| | - Zhongwu Li
- Materials Science Division, Physical and Life Science Directorate, Lawrence Livermore National Laboratory, Livermore, California94550, United States
| | - Arun Majumdar
- Department of Mechanical Engineering, Stanford University, Stanford, California94305, United States
| | - Joel Martis
- Department of Mechanical Engineering, Stanford University, Stanford, California94305, United States
| | - Rahul Prasanna Misra
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts02139, United States
| | - Aleksandr Noy
- Materials Science Division, Physical and Life Science Directorate, Lawrence Livermore National Laboratory, Livermore, California94550, United States
- School of Natural Sciences, University of California Merced, Merced, California95344, United States
| | - Tuan Anh Pham
- Materials Science Division, Physical and Life Science Directorate, Lawrence Livermore National Laboratory, Livermore, California94550, United States
| | - Haoran Qu
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland20742, United States
| | - Archith Rayabharam
- Oden Institute for Computational Engineering and Sciences, Walker Department of Mechanical Engineering, The University of Texas at Austin, Austin, 78712TexasUnited States
| | - Mark A Reed
- Department of Electrical Engineering, Yale University, 15 Prospect Street, New Haven, Connecticut06520, United States
| | - Cody L Ritt
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut06520-8286, United States
| | - Eric Schwegler
- Materials Science Division, Physical and Life Science Directorate, Lawrence Livermore National Laboratory, Livermore, California94550, United States
| | - Zuzanna Siwy
- Department of Physics and Astronomy, Department of Chemistry, Department of Biomedical Engineering, University of California, Irvine, Irvine92697, United States
| | - Michael S Strano
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts02139, United States
| | - YuHuang Wang
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland20742, United States
- Maryland NanoCenter, University of Maryland, College Park, Maryland20742, United States
| | - Yun-Chiao Yao
- Materials Science Division, Physical and Life Science Directorate, Lawrence Livermore National Laboratory, Livermore, California94550, United States
- School of Natural Sciences, University of California Merced, Merced, California95344, United States
| | - Cheng Zhan
- Materials Science Division, Physical and Life Science Directorate, Lawrence Livermore National Laboratory, Livermore, California94550, United States
| | - Ze Zhang
- Department of Mechanical Engineering, Stanford University, Stanford, California94305, United States
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24
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Cheng J, Liu T, You X, Zhang F, Sui SF, Wan X, Zhang X. Determining protein structures in cellular lamella at pseudo-atomic resolution by GisSPA. Nat Commun 2023; 14:1282. [PMID: 36922493 PMCID: PMC10017804 DOI: 10.1038/s41467-023-36175-y] [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: 07/14/2022] [Accepted: 01/18/2023] [Indexed: 03/17/2023] Open
Abstract
Cryo-electron tomography is a major tool used to study the structure of protein complexes in situ. However, the throughput of tilt-series image data collection is still quite low. Here, we show that GisSPA, a GPU accelerated program, can translationally and rotationally localize the target protein complex in cellular lamellae, as prepared with a focused ion beam, using single cryo-electron microscopy images without tilt-series, and reconstruct the protein complex at near-atomic resolution. GisSPA allows high-throughput data collection without the acquisition of tilt-series images and reconstruction of the tomogram, which is essential for high-resolution reconstruction of asymmetric or low-symmetry protein complexes. We demonstrate the power of GisSPA with 3.4-Å and 3.9-Å resolutions of resolving phycobilisome and tetrameric photosystem II complex structures in cellular lamellae, respectively. In this work, we present GisSPA as a practical tool that facilitates high-resolution in situ protein structure determination.
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Affiliation(s)
- Jing Cheng
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Tong Liu
- High Performance Computer Research Center, Institute of Computing Technology, Chinese Academy of Sciences, Beijing, 100190, China
| | - Xin You
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Fa Zhang
- Beijing Institute of Technology, Beijing, 100081, China
| | - Sen-Fang Sui
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Xiaohua Wan
- Beijing Institute of Technology, Beijing, 100081, China.
| | - Xinzheng Zhang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.
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25
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Harrison PJ, Vecerkova T, Clare DK, Quigley A. A review of the approaches used to solve sub-100 kDa membrane proteins by cryo-electron microscopy. J Struct Biol 2023; 215:107959. [PMID: 37004781 DOI: 10.1016/j.jsb.2023.107959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 03/07/2023] [Accepted: 03/28/2023] [Indexed: 04/03/2023]
Abstract
Membrane proteins (MPs) are essential components of all biological membranes, contributing to key cellular functions that include signalling, molecular transport and energy metabolism. Consequently, MPs are important biomedical targets for therapeutics discovery. Despite hardware and software developments in cryo-electron microscopy, as well as MP sample preparation, MPs smaller than 100 kDa remain difficult to study structurally. Significant investment is required to overcome low levels of naturally abundant protein, MP hydrophobicity as well as conformational and compositional instability. Here we have reviewed the sample preparation approaches that have been taken to successfully express, purify and prepare small MPs for analysis by cryo-EM (those with a total solved molecular weight of under 100 kDa), as well as examining the differing approaches towards data processing and ultimately obtaining a structural solution. We highlight common challenges at each stage in the process as well as strategies that have been developed to overcome these issues. Finally, we discuss future directions and opportunities for the study of sub-100 kDa membrane proteins by cryo-EM.
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26
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Berger C, Dumoux M, Glen T, Yee NBY, Mitchels JM, Patáková Z, Darrow MC, Naismith JH, Grange M. Plasma FIB milling for the determination of structures in situ. Nat Commun 2023; 14:629. [PMID: 36746945 PMCID: PMC9902539 DOI: 10.1038/s41467-023-36372-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Accepted: 01/26/2023] [Indexed: 02/08/2023] Open
Abstract
Structural biology studies inside cells and tissues require methods to thin vitrified specimens to electron transparency. Until now, focused ion beams based on gallium have been used. However, ion implantation, changes to surface chemistry and an inability to access high currents limit gallium application. Here, we show that plasma-coupled ion sources can produce cryogenic lamellae of vitrified human cells in a robust and automated manner, with quality sufficient for pseudo-atomic structure determination. Lamellae were produced in a prototype microscope equipped for long cryogenic run times (> 1 week) and with multi-specimen support fully compatible with modern-day transmission electron microscopes. We demonstrate that plasma ion sources can be used for structural biology within cells, determining a structure in situ to 4.9 Å, and characterise the resolution dependence on particle distance from the lamella edge. We describe a workflow upon which different plasmas can be examined to further streamline lamella fabrication.
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Affiliation(s)
- Casper Berger
- Structural Biology, The Rosalind Franklin Institute, Harwell Science & Innovation Campus, Didcot, OX11 0QS, United Kingdom.,Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, OX3 7BN, Oxford, United Kingdom
| | - Maud Dumoux
- Structural Biology, The Rosalind Franklin Institute, Harwell Science & Innovation Campus, Didcot, OX11 0QS, United Kingdom
| | - Thomas Glen
- Structural Biology, The Rosalind Franklin Institute, Harwell Science & Innovation Campus, Didcot, OX11 0QS, United Kingdom
| | - Neville B-Y Yee
- Artificial Intelligence & Informatics, The Rosalind Franklin Institute, Harwell Science & Innovation Campus, Didcot, OX11 0QS, United Kingdom
| | - John M Mitchels
- Thermo Fisher Scientific Brno s.r.o, Brno, 627 00, Czech Republic
| | - Zuzana Patáková
- Thermo Fisher Scientific Brno s.r.o, Brno, 627 00, Czech Republic
| | - Michele C Darrow
- Artificial Intelligence & Informatics, The Rosalind Franklin Institute, Harwell Science & Innovation Campus, Didcot, OX11 0QS, United Kingdom
| | - James H Naismith
- Structural Biology, The Rosalind Franklin Institute, Harwell Science & Innovation Campus, Didcot, OX11 0QS, United Kingdom.,Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, OX3 7BN, Oxford, United Kingdom
| | - Michael Grange
- Structural Biology, The Rosalind Franklin Institute, Harwell Science & Innovation Campus, Didcot, OX11 0QS, United Kingdom. .,Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, OX3 7BN, Oxford, United Kingdom.
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27
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Neselu K, Wang B, Rice WJ, Potter CS, Carragher B, Chua EY. Measuring the effects of ice thickness on resolution in single particle cryo-EM. J Struct Biol X 2023; 7:100085. [PMID: 36742017 PMCID: PMC9894782 DOI: 10.1016/j.yjsbx.2023.100085] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 01/10/2023] [Accepted: 01/23/2023] [Indexed: 01/25/2023] Open
Abstract
Ice thickness is a critical parameter in single particle cryo-EM - too thin ice can break during imaging or exclude the sample of interest, while ice that is too thick contributes to more inelastic scattering that precludes obtaining high resolution reconstructions. Here we present the practical effects of ice thickness on resolution, and the influence of energy filters, accelerating voltage, or detector mode. We collected apoferritin data with a wide range of ice thicknesses on three microscopes with different instrumentation and settings. We show that on a 300 kV microscope, using a 20 eV energy filter slit has a greater effect on improving resolution in thicker ice; that operating at 300 kV instead of 200 kV accelerating voltage provides significant resolution improvements at an ice thickness above 150 nm; and that on a 200 kV microscope using a detector operating in super resolution mode enables good reconstructions for up to 200 nm ice thickness, while collecting in counting instead of linear mode leads to improvements in resolution for ice of 50-150 nm thickness. Our findings can serve as a guide for users seeking to optimize data collection or sample preparation routines for both single particle and in situ cryo-EM. We note that most in situ data collection is done on samples in a range of ice thickness above 150 nm so these results may be especially relevant to that community.
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Affiliation(s)
- Kasahun Neselu
- Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, USA
| | - Bing Wang
- Cryo-Electron Microscopy Core, New York University Grossman School of Medicine, New York, NY, USA
| | - William J. Rice
- Cryo-Electron Microscopy Core, New York University Grossman School of Medicine, New York, NY, USA,Department of Cell Biology, New York University Grossman School of Medicine, New York, NY, USA
| | - Clinton S. Potter
- Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, USA
| | - Bridget Carragher
- Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, USA,Corresponding authors.
| | - Eugene Y.D. Chua
- Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, USA,Corresponding authors.
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28
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Cheng A, Kim PT, Kuang H, Mendez JH, Chua EYD, Maruthi K, Wei H, Sawh A, Aragon MF, Serbynovskyi V, Neselu K, Eng ET, Potter CS, Carragher B, Bepler T, Noble AJ. Fully automated multi-grid cryoEM screening using Smart Leginon. IUCRJ 2023; 10:77-89. [PMID: 36598504 PMCID: PMC9812217 DOI: 10.1107/s2052252522010624] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 11/03/2022] [Indexed: 06/17/2023]
Abstract
Single-particle cryo-electron microscopy (cryoEM) is a swiftly growing method for understanding protein structure. With increasing demand for high-throughput, high-resolution cryoEM services comes greater demand for rapid and automated cryoEM grid and sample screening. During screening, optimal grids and sample conditions are identified for subsequent high-resolution data collection. Screening is a major bottleneck for new cryoEM projects because grids must be optimized for several factors, including grid type, grid hole size, sample concentration, buffer conditions, ice thickness and particle behavior. Even for mature projects, multiple grids are commonly screened to select a subset for high-resolution data collection. Here, machine learning and novel purpose-built image-processing and microscope-handling algorithms are incorporated into the automated data-collection software Leginon, to provide an open-source solution for fully automated high-throughput grid screening. This new version, broadly called Smart Leginon, emulates the actions of an operator in identifying areas on the grid to explore as potentially useful for data collection. Smart Leginon Autoscreen sequentially loads and examines grids from an automated specimen-exchange system to provide completely unattended grid screening across a set of grids. Comparisons between a multi-grid autoscreen session and conventional manual screening by 5 expert microscope operators are presented. On average, Autoscreen reduces operator time from ∼6 h to <10 min and provides a percentage of suitable images for evaluation comparable to the best operator. The ability of Smart Leginon to target holes that are particularly difficult to identify is analyzed. Finally, the utility of Smart Leginon is illustrated with three real-world multi-grid user screening/collection sessions, demonstrating the efficiency and flexibility of the software package. The fully automated functionality of Smart Leginon significantly reduces the burden on operator screening time, improves the throughput of screening and recovers idle microscope time, thereby improving availability of cryoEM services.
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Affiliation(s)
- Anchi Cheng
- Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, USA
| | - Paul T. Kim
- Simons Machine Learning Center, New York Structural Biology Center, New York, NY, USA
| | - Huihui Kuang
- Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, USA
| | - Joshua H. Mendez
- Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, USA
| | - Eugene Y. D. Chua
- Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, USA
| | - Kashyap Maruthi
- Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, USA
| | - Hui Wei
- Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, USA
| | - Anjelique Sawh
- Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, USA
| | - Mahira F. Aragon
- Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, USA
| | | | - Kasahun Neselu
- Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, USA
| | - Edward T. Eng
- Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, USA
| | - Clinton S. Potter
- Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, USA
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Bridget Carragher
- Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, USA
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Tristan Bepler
- Simons Machine Learning Center, New York Structural Biology Center, New York, NY, USA
| | - Alex J. Noble
- Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, USA
- Simons Machine Learning Center, New York Structural Biology Center, New York, NY, USA
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29
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Bhattacharjee B, Rahman MM, Hibbs RE, Stowell MHB. A simple flash and freeze system for cryogenic time-resolved electron microscopy. Front Mol Biosci 2023; 10:1129225. [PMID: 36959978 PMCID: PMC10028177 DOI: 10.3389/fmolb.2023.1129225] [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: 12/21/2022] [Accepted: 02/16/2023] [Indexed: 03/09/2023] Open
Abstract
As the resolution revolution in CryoEM expands to encompass all manner of macromolecular complexes, an important new frontier is the implementation of cryogenic time resolved EM (cryoTREM). Biological macromolecular complexes are dynamic systems that undergo conformational changes on timescales from microseconds to minutes. Understanding the dynamic nature of biological changes is critical to understanding function. To realize the full potential of CryoEM, time resolved methods will be integral in coupling static structures to dynamic functions. Here, we present an LED-based photo-flash system as a core part of the sample preparation phase in CryoTREM. The plug-and-play system has a wide range of operational parameters, is low cost and ensures uniform irradiation and minimal heating of the sample prior to plunge freezing. The complete design including electronics and optics, manufacturing, control strategies and operating procedures are discussed for the Thermo Scientific™ Vitrobot and Leica™ EM GP2 plunge freezers. Possible adverse heating effects on the biological sample are also addressed through theoretical as well as experimental studies.
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Affiliation(s)
- Biddut Bhattacharjee
- University of Colorado Boulder, Boulder, United States
- *Correspondence: Biddut Bhattacharjee, ; Michael H. B. Stowell,
| | | | - Ryan E. Hibbs
- University of Texas Southwestern Medical Center, Dallas, United States
| | - Michael H. B. Stowell
- University of Colorado Boulder, Boulder, United States
- *Correspondence: Biddut Bhattacharjee, ; Michael H. B. Stowell,
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30
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Zheng L, Liu N, Gao X, Zhu W, Liu K, Wu C, Yan R, Zhang J, Gao X, Yao Y, Deng B, Xu J, Lu Y, Liu Z, Li M, Wei X, Wang HW, Peng H. Uniform thin ice on ultraflat graphene for high-resolution cryo-EM. Nat Methods 2023; 20:123-130. [PMID: 36522503 PMCID: PMC9834055 DOI: 10.1038/s41592-022-01693-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 10/20/2022] [Indexed: 12/23/2022]
Abstract
Cryo-electron microscopy (cryo-EM) visualizes the atomic structure of macromolecules that are embedded in vitrified thin ice at their close-to-native state. However, the homogeneity of ice thickness, a key factor to ensure high image quality, is poorly controlled during specimen preparation and has become one of the main challenges for high-resolution cryo-EM. Here we found that the uniformity of thin ice relies on the surface flatness of the supporting film, and developed a method to use ultraflat graphene (UFG) as the support for cryo-EM specimen preparation to achieve better control of vitreous ice thickness. We show that the uniform thin ice on UFG improves the image quality of vitrified specimens. Using such a method we successfully determined the three-dimensional structures of hemoglobin (64 kDa), α-fetoprotein (67 kDa) with no symmetry, and streptavidin (52 kDa) at a resolution of 3.5 Å, 2.6 Å and 2.2 Å, respectively. Furthermore, our results demonstrate the potential of UFG for the fields of cryo-electron tomography and structure-based drug discovery.
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Affiliation(s)
- Liming Zheng
- Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
- Beijing Graphene Institute (BGI), Beijing, China
| | - Nan Liu
- Ministry of Education Key Laboratory of Protein Sciences, Beijing Frontier Research Center for Biological Structures, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China.
| | - Xiaoyin Gao
- Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | - Wenqing Zhu
- State Key Laboratory for Turbulence and Complex System, Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing, China
| | - Kun Liu
- Hainan Provincial Key Laboratory of Carcinogenesis and Intervention, Hainan Medical College, Haikou, China
- Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
| | - Cang Wu
- Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
| | - Rui Yan
- Beijing Graphene Institute (BGI), Beijing, China
| | - Jincan Zhang
- Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Xin Gao
- Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Yating Yao
- Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | - Bing Deng
- Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | - Jie Xu
- Ministry of Education Key Laboratory of Protein Sciences, Beijing Frontier Research Center for Biological Structures, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
- Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing, China
| | - Ye Lu
- Ministry of Education Key Laboratory of Protein Sciences, Beijing Frontier Research Center for Biological Structures, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
- Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing, China
| | - Zhongmin Liu
- Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
| | - Mengsen Li
- Hainan Provincial Key Laboratory of Carcinogenesis and Intervention, Hainan Medical College, Haikou, China
| | - Xiaoding Wei
- State Key Laboratory for Turbulence and Complex System, Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing, China.
- Beijing Innovation Center for Engineering Science and Advanced Technology, Peking University, Beijing, China.
- Peking University Nanchang Innovation Institute, Nanchang, China.
| | - Hong-Wei Wang
- Ministry of Education Key Laboratory of Protein Sciences, Beijing Frontier Research Center for Biological Structures, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China.
- Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing, China.
| | - Hailin Peng
- Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, China.
- Beijing Graphene Institute (BGI), Beijing, China.
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.
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31
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Guaita M, Watters SC, Loerch S. Recent advances and current trends in cryo-electron microscopy. Curr Opin Struct Biol 2022; 77:102484. [PMID: 36323134 DOI: 10.1016/j.sbi.2022.102484] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 08/13/2022] [Accepted: 09/21/2022] [Indexed: 12/14/2022]
Abstract
All steps of cryogenic electron-microscopy (cryo-EM) workflows have rapidly evolved over the last decade. Advances in both single-particle analysis (SPA) cryo-EM and cryo-electron tomography (cryo-ET) have facilitated the determination of high-resolution biomolecular structures that are not tractable with other methods. However, challenges remain. For SPA, these include improved resolution in an additional dimension: time. For cryo-ET, these include accessing difficult-to-image areas of a cell and finding rare molecules. Finally, there is a need for automated and faster workflows, as many projects are limited by throughput. Here, we review current developments in SPA cryo-EM and cryo-ET that push these boundaries. Collectively, these advances are poised to propel our spatial and temporal understanding of macromolecular processes.
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Affiliation(s)
- Margherita Guaita
- University of California, Santa Cruz, Department of Chemistry and Biochemistry, Santa Cruz, CA, USA
| | - Scott C Watters
- University of California, Santa Cruz, Department of Chemistry and Biochemistry, Santa Cruz, CA, USA
| | - Sarah Loerch
- University of California, Santa Cruz, Department of Chemistry and Biochemistry, Santa Cruz, CA, USA.
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32
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Elferich J, Schiroli G, Scadden DT, Grigorieff N. Defocus Corrected Large Area Cryo-EM (DeCo-LACE) for label-free detection of molecules across entire cell sections. eLife 2022; 11:e80980. [PMID: 36382886 PMCID: PMC9711527 DOI: 10.7554/elife.80980] [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: 06/10/2022] [Accepted: 11/15/2022] [Indexed: 11/17/2022] Open
Abstract
A major goal of biological imaging is localization of biomolecules inside a cell. Fluorescence microscopy can localize biomolecules inside whole cells and tissues, but its ability to count biomolecules and accuracy of the spatial coordinates is limited by the wavelength of visible light. Cryo-electron microscopy (cryo-EM) provides highly accurate position and orientation information of biomolecules but is often confined to small fields of view inside a cell, limiting biological context. In this study, we use a new data-acquisition scheme called Defocus-Corrected Large-Area cryo-EM (DeCo-LACE) to collect high-resolution images of entire sections (100- to 250-nm-thick lamellae) of neutrophil-like mouse cells, representing 1-2% of the total cellular volume. We use 2D template matching (2DTM) to determine localization and orientation of the large ribosomal subunit in these sections. These data provide maps of ribosomes across entire sections of mammalian cells. This high-throughput cryo-EM data collection approach together with 2DTM will advance visual proteomics and provide biological insight that cannot be obtained by other methods.
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Affiliation(s)
- Johannes Elferich
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Howard Hughes Medical InstituteWorcesterUnited States
| | - Giulia Schiroli
- Department of Stem Cell and Regenerative Biology, Harvard UniversityCambridgeUnited States
- Harvard Stem Cell InstituteCambridgeUnited States
- Center for Regenerative Medicine, Massachusetts General HospitalBostonUnited States
| | - David T Scadden
- Department of Stem Cell and Regenerative Biology, Harvard UniversityCambridgeUnited States
- Harvard Stem Cell InstituteCambridgeUnited States
- Center for Regenerative Medicine, Massachusetts General HospitalBostonUnited States
| | - Nikolaus Grigorieff
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Howard Hughes Medical InstituteWorcesterUnited States
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33
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Kreutzberger MAB, Sonani RR, Liu J, Chatterjee S, Wang F, Sebastian AL, Biswas P, Ewing C, Zheng W, Poly F, Frankel G, Luisi BF, Calladine CR, Krupovic M, Scharf BE, Egelman EH. Convergent evolution in the supercoiling of prokaryotic flagellar filaments. Cell 2022; 185:3487-3500.e14. [PMID: 36057255 PMCID: PMC9500442 DOI: 10.1016/j.cell.2022.08.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 07/04/2022] [Accepted: 08/04/2022] [Indexed: 02/02/2023]
Abstract
The supercoiling of bacterial and archaeal flagellar filaments is required for motility. Archaeal flagellar filaments have no homology to their bacterial counterparts and are instead homologs of bacterial type IV pili. How these prokaryotic flagellar filaments, each composed of thousands of copies of identical subunits, can form stable supercoils under torsional stress is a fascinating puzzle for which structural insights have been elusive. Advances in cryoelectron microscopy (cryo-EM) make it now possible to directly visualize the basis for supercoiling, and here, we show the atomic structures of supercoiled bacterial and archaeal flagellar filaments. For the bacterial flagellar filament, we identify 11 distinct protofilament conformations with three broad classes of inter-protomer interface. For the archaeal flagellar filament, 10 protofilaments form a supercoil geometry supported by 10 distinct conformations, with one inter-protomer discontinuity creating a seam inside of the curve. Our results suggest that convergent evolution has yielded stable superhelical geometries that enable microbial locomotion.
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Affiliation(s)
- Mark A B Kreutzberger
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA 22903, USA
| | - Ravi R Sonani
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA 22903, USA
| | - Junfeng Liu
- Institut Pasteur, Université Paris Cité, CNRS UMR 6047, Archaeal Virology Unit, 75015 Paris, France
| | - Sharanya Chatterjee
- Centre for Molecular Microbiology and Infection, Department of Life Sciences, Imperial College London, London, UK
| | - Fengbin Wang
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA 22903, USA
| | - Amanda L Sebastian
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, USA
| | - Priyanka Biswas
- Centre for Molecular Microbiology and Infection, Department of Life Sciences, Imperial College London, London, UK
| | - Cheryl Ewing
- Enteric Diseases Department, Naval Medical Research Center, Silver Spring, MD 20910, USA
| | - Weili Zheng
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA 22903, USA
| | - Frédéric Poly
- Enteric Diseases Department, Naval Medical Research Center, Silver Spring, MD 20910, USA
| | - Gad Frankel
- Centre for Molecular Microbiology and Infection, Department of Life Sciences, Imperial College London, London, UK
| | - B F Luisi
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1GA, UK
| | - Chris R Calladine
- Department of Engineering, University of Cambridge, Trumpington Street, Cambridge CB2 1PZ, UK
| | - Mart Krupovic
- Institut Pasteur, Université Paris Cité, CNRS UMR 6047, Archaeal Virology Unit, 75015 Paris, France
| | - Birgit E Scharf
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, USA
| | - Edward H Egelman
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA 22903, USA.
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34
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Hohle MM, Lammens K, Gut F, Wang B, Kahler S, Kugler K, Till M, Beckmann R, Hopfner KP, Jung C. Ice thickness monitoring for cryo-EM grids by interferometry imaging. Sci Rep 2022; 12:15330. [PMID: 36097274 PMCID: PMC9468024 DOI: 10.1038/s41598-022-16978-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 07/19/2022] [Indexed: 11/16/2022] Open
Abstract
While recent technological developments contributed to breakthrough advances in single particle cryo-electron microscopy (cryo-EM), sample preparation remains a significant bottleneck for the structure determination of macromolecular complexes. A critical time factor is sample optimization that requires the use of an electron microscope to screen grids prepared under different conditions to achieve the ideal vitreous ice thickness containing the particles. Evaluating sample quality requires access to cryo-electron microscopes and a strong expertise in EM. To facilitate and accelerate the selection procedure of probes suitable for high-resolution cryo-EM, we devised a method to assess the vitreous ice layer thickness of sample coated grids. The experimental setup comprises an optical interferometric microscope equipped with a cryogenic stage and image analysis software based on artificial neural networks (ANN) for an unbiased sample selection. We present and validate this approach for different protein complexes and grid types, and demonstrate its performance for the assessment of ice quality. This technique is moderate in cost and can be easily performed on a laboratory bench. We expect that its throughput and its versatility will contribute to facilitate the sample optimization process for structural biologists.
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Affiliation(s)
- Markus Matthias Hohle
- Gene Center and Department of Biochemistry, (CIPSM), Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, 81377, München, Germany
| | - Katja Lammens
- Gene Center and Department of Biochemistry, (CIPSM), Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, 81377, München, Germany
| | - Fabian Gut
- Gene Center and Department of Biochemistry, (CIPSM), Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, 81377, München, Germany
| | - Bingzhi Wang
- Gene Center and Department of Biochemistry, (CIPSM), Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, 81377, München, Germany
| | - Sophia Kahler
- Gene Center and Department of Biochemistry, (CIPSM), Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, 81377, München, Germany
| | | | - Michael Till
- Gene Center and Department of Biochemistry, (CIPSM), Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, 81377, München, Germany
| | - Roland Beckmann
- Gene Center and Department of Biochemistry, (CIPSM), Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, 81377, München, Germany
| | - Karl-Peter Hopfner
- Gene Center and Department of Biochemistry, (CIPSM), Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, 81377, München, Germany
| | - Christophe Jung
- Gene Center and Department of Biochemistry, (CIPSM), Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, 81377, München, Germany.
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35
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Brown HG, Hanssen E. MeasureIce: accessible on-the-fly measurement of ice thickness in cryo-electron microscopy. Commun Biol 2022; 5:817. [PMID: 35965271 PMCID: PMC9376182 DOI: 10.1038/s42003-022-03698-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 07/11/2022] [Indexed: 11/12/2022] Open
Abstract
Ice thickness is arguably one of the most important factors limiting the resolution of protein structures determined by cryo-electron microscopy (cryo-EM). The amorphous atomic structure of the ice that stabilizes and protects biological samples in cryo-EM grids also imprints some additional noise in cryo-EM images. Ice that is too thick jeopardizes the success of particle picking and reconstruction of the biomolecule in the worst case and, at best, deteriorates eventual map resolution. Minimizing the thickness of the ice layer and thus the magnitude of its noise contribution is thus imperative in cryo-EM grid preparation. In this paper we introduce MeasureIce, a simple, easy to use ice thickness measurement tool for screening and selecting acquisition areas of cryo-EM grids. We show that it is possible to simulate thickness-image intensity look-up tables, also usable in SerialEM and Leginon, using elementary scattering physics and thereby adapt the tool to any microscope without time consuming experimental calibration. We benchmark our approach using two alternative techniques: the “ice channel” technique and tilt-series tomography. We also demonstrate the utility of ice thickness measurement for selecting holes in gold grids containing an Equine apoferritin sample, achieving a 1.88 Ångstrom resolution in subsequent refinement of the atomic map. MeasureIce is an ice thickness measurement tool for screening and selecting acquisition areas of cryo-EM grids.
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Affiliation(s)
- Hamish G Brown
- Ian Holmes Imaging Center, Bio21 Molecular Science & Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia.
| | - Eric Hanssen
- Ian Holmes Imaging Center, Bio21 Molecular Science & Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia.,Department of Biochemistry and Pharmacology and ARC Industrial Transformation Training Center for Cryo-electron Microscopy of Membrane Proteins, The University of Melbourne, Parkville, Victoria, Australia
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36
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Owji AP, Wang J, Kittredge A, Clark Z, Zhang Y, Hendrickson WA, Yang T. Structures and gating mechanisms of human bestrophin anion channels. Nat Commun 2022; 13:3836. [PMID: 35789156 PMCID: PMC9253114 DOI: 10.1038/s41467-022-31437-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 06/17/2022] [Indexed: 01/16/2023] Open
Abstract
Bestrophin-1 (Best1) and bestrophin-2 (Best2) are two members of the bestrophin family of calcium (Ca2+)-activated chloride (Cl−) channels with critical involvement in ocular physiology and direct pathological relevance. Here, we report cryo-EM structures of wild-type human Best1 and Best2 in various states at up to 1.8 Å resolution. Ca2+-bound Best1 structures illustrate partially open conformations at the two Ca2+-dependent gates of the channels, in contrast to the fully open conformations observed in Ca2+-bound Best2, which is in accord with the significantly smaller currents conducted by Best1 in electrophysiological recordings. Comparison of the closed and open states reveals a C-terminal auto-inhibitory segment (AS), which constricts the channel concentrically by wrapping around the channel periphery in an inter-protomer manner and must be released to allow channel opening. Our results demonstrate that removing the AS from Best1 and Best2 results in truncation mutants with similar activities, while swapping the AS between Best1 and Best2 results in chimeric mutants with swapped activities, underlying a key role of the AS in determining paralog specificity among bestrophins. Bestrophin channels are critical for physiology of the eye. Here, authors report cryo-EM structures of human bestrophins in various states at up to 1.8 Å resolution, revealing paralog-specific features that underlie molecular mechanisms of permeation.
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Affiliation(s)
- Aaron P Owji
- Department of Ophthalmology, Columbia University, New York, NY, USA.,Department of Pharmacology, Columbia University, New York, NY, USA
| | - Jiali Wang
- Department of Ophthalmology, Columbia University, New York, NY, USA
| | - Alec Kittredge
- Department of Ophthalmology, Columbia University, New York, NY, USA.,Department of Pharmacology, Columbia University, New York, NY, USA
| | - Zada Clark
- Department of Ophthalmology, Columbia University, New York, NY, USA
| | - Yu Zhang
- Department of Ophthalmology, Columbia University, New York, NY, USA.
| | - Wayne A Hendrickson
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA. .,Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA. .,New York Structural Biology Center, New York, NY, USA.
| | - Tingting Yang
- Department of Ophthalmology, Columbia University, New York, NY, USA.
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37
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Huntington B, Zhao L, Bron P, Shahul Hameed UF, Arold ST, Qureshi BM. Thicker Ice Improves the Integrity and Angular Distribution of CDC48A Hexamers on Cryo-EM Grids. Front Mol Biosci 2022; 9:890390. [PMID: 35782862 PMCID: PMC9247313 DOI: 10.3389/fmolb.2022.890390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Accepted: 05/26/2022] [Indexed: 11/21/2022] Open
Abstract
Many cryogenic electron microscopy (cryo-EM) single particle analyses are constrained by the sample preparation step upon which aggregation, dissociation, and/or preferential orientation of particles can be introduced. Here, we report how we solved these problems in the case of CDC48A, a hexameric AAA ATPase from Arabidopsis thaliana. CDC48A hexamers are well preserved under negative staining conditions but disassemble during grid freezing using the classical blotting method. Vitrification of grids using the blot-free Chameleon method preserved the integrity of particles but resulted in their strong preferential orientation. We then used a strategy where we improved in parallel the purification of CDC48A and the conditions for cryo-EM data acquisition. Indeed, we noted that images taken from thicker ice presented an even distribution of intact particles with random orientations, but resulted in a lower image resolution. Consequently, in our case, distribution, orientation, image resolution, and the integrity of particles were tightly correlated with ice thickness. By combining the more homogeneous and stable CDC48A hexamers resulting from our improved purification protocol with an iterative search across different ice thicknesses, we identified an intermediate thickness that retained sufficiently high-resolution structural information while maintaining a complete distribution of particle orientations. Our approach may provide a simple, fast, and generally applicable strategy to record data of sufficient quality under standard laboratory and microscope settings. This method may be of particular value when time and resources are limited.
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Affiliation(s)
- Brandon Huntington
- Bioscience Program, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
- Computational Biology Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Lingyun Zhao
- Imaging and Characterization Core Lab, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Patrick Bron
- Centre de Biologie Structurale (CBS), INSERM, CNRS, Université de Montpellier, Montpellier, France
| | - Umar F. Shahul Hameed
- Bioscience Program, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
- Computational Biology Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
- *Correspondence: Umar F. Shahul Hameed, ; Stefan T. Arold, ; Bilal M. Qureshi,
| | - Stefan T. Arold
- Bioscience Program, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
- Computational Biology Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
- Centre de Biologie Structurale (CBS), INSERM, CNRS, Université de Montpellier, Montpellier, France
- *Correspondence: Umar F. Shahul Hameed, ; Stefan T. Arold, ; Bilal M. Qureshi,
| | - Bilal M. Qureshi
- Bioscience Program, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
- Computational Biology Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
- Division of Structural Biology (Strubi), University of Oxford, Oxford, United Kingdom
- Scientific Center of Optical and Electron Microscopy (ScopeM), ETH Zurich, Zurich, Switzerland
- *Correspondence: Umar F. Shahul Hameed, ; Stefan T. Arold, ; Bilal M. Qureshi,
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38
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Hagen WJH. Light ‘Em up: Efficient Screening of Gold Foil Grids in Cryo-EM. Front Mol Biosci 2022; 9:912363. [PMID: 35693551 PMCID: PMC9184724 DOI: 10.3389/fmolb.2022.912363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 05/11/2022] [Indexed: 11/13/2022] Open
Abstract
Transmission electron cryo-microscopy (cryo-EM) allows for obtaining 3D structural information by imaging macromolecules embedded in thin layers of amorphous ice. To obtain high-resolution structural information, samples need to be thin to minimize inelastic scattering which blurs images. During data collection sessions, time spent on finding areas on the cryo-EM grid with optimal ice thickness should be minimized as imaging time on high-end Transmission Electron Microscope TEM systems is costly. Recently, grids covered with thin gold films have become popular due to their stability and reduced beam-induced motion of the sample. Gold foil grids have substantially different densities between the gold foil and ice, effectively resulting in the loss of dynamic range between thin and thick regions of ice, making it challenging to find areas with suitable ice thickness efficiently during grid screening and thus increase expensive imaging time. Here, an energy filter-based plasmon imaging is presented as a fast and easy method for grid screening of the gold foil grids.
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39
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Han BG, Armstrong M, Fletcher DA, Glaeser RM. Perspective: Biochemical and Physical Constraints Associated With Preparing Thin Specimens for Single-Particle Cryo-EM. Front Mol Biosci 2022; 9:864829. [PMID: 35573724 PMCID: PMC9100935 DOI: 10.3389/fmolb.2022.864829] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 03/25/2022] [Indexed: 11/13/2022] Open
Abstract
While many aspects of single-particle electron cryo-microscopy (cryo-EM) of biological macromolecules have reached a sophisticated level of development, this is not yet the case when it comes to preparing thin samples on specimen grids. As a result, there currently is considerable interest in achieving better control of both the sample thickness and the amount of area that is useful, but this is only one aspect in which improvement is needed. This Perspective addresses the further need to prevent the macromolecular particles from making contact with the air-water interface, something that can result in preferential orientation and even structural disruption of macromolecular particles. This unwanted contact can occur either as the result of free diffusion of particles during the interval between application, thinning and vitrification of the remaining buffer, or-when particles have been immobilized-by the film of buffer becoming too thin prior to vitrification. An opportunity now exists to apply theoretical and practical insights from the fields of thin-film physical chemistry and interfacial science, in an effort to bring cryo-EM sample preparation to a level of sophistication that is comparable to that of current data collection and analysis.
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Affiliation(s)
- Bong-Gyoon Han
- Lawrence Berkeley National Laboratory, University of California, Berkeley, Berkeley, CA, United States
| | - Max Armstrong
- Lawrence Berkeley National Laboratory, University of California, Berkeley, Berkeley, CA, United States,Department of Bioengineering, University of California, Berkeley, Berkeley, CA, United States
| | - Daniel A. Fletcher
- Department of Bioengineering, University of California, Berkeley, Berkeley, CA, United States,Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, Berkeley, CA, United States,Chan Zuckerberg Biohub, San Francisco, CA, United States
| | - Robert M. Glaeser
- Lawrence Berkeley National Laboratory, University of California, Berkeley, Berkeley, CA, United States,*Correspondence: Robert M. Glaeser,
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40
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Olek M, Cowtan K, Webb D, Chaban Y, Zhang P. IceBreaker: Software for high-resolution single-particle cryo-EM with non-uniform ice. Structure 2022; 30:522-531.e4. [PMID: 35150604 PMCID: PMC9033277 DOI: 10.1016/j.str.2022.01.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 12/01/2021] [Accepted: 01/18/2022] [Indexed: 12/23/2022]
Abstract
Despite the abundance of available software tools, optimal particle selection is still a vital issue in single-particle cryoelectron microscopy (cryo-EM). Regardless of the method used, most pickers struggle when ice thickness varies on a micrograph. IceBreaker allows users to estimate the relative ice gradient and flatten it by equalizing the local contrast. It allows the differentiation of particles from the background and improves overall particle picking performance. Furthermore, we introduce an additional parameter corresponding to local ice thickness for each particle. Particles with a defined ice thickness can be grouped and filtered based on this parameter during processing. These functionalities are especially valuable for on-the-fly processing to automatically pick as many particles as possible from each micrograph and to select optimal regions for data collection. Finally, estimated ice gradient distributions can be stored separately and used to inspect the quality of prepared samples.
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Affiliation(s)
- Mateusz Olek
- Electron Bio-Imaging Centre, Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, UK; Department of Chemistry, University of York, York, UK
| | - Kevin Cowtan
- Department of Chemistry, University of York, York, UK
| | - Donovan Webb
- Electron Bio-Imaging Centre, Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, UK
| | - Yuriy Chaban
- Electron Bio-Imaging Centre, Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, UK.
| | - Peijun Zhang
- Electron Bio-Imaging Centre, Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, UK; Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK; Chinese Academy of Medical Sciences Oxford Institute, University of Oxford, Oxford OX3 7BN, UK.
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41
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Bock LV, Grubmüller H. Effects of cryo-EM cooling on structural ensembles. Nat Commun 2022; 13:1709. [PMID: 35361752 PMCID: PMC8971465 DOI: 10.1038/s41467-022-29332-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 03/10/2022] [Indexed: 01/01/2023] Open
Abstract
Structure determination by cryo electron microscopy (cryo-EM) provides information on structural heterogeneity and ensembles at atomic resolution. To obtain cryo-EM images of macromolecules, the samples are first rapidly cooled down to cryogenic temperatures. To what extent the structural ensemble is perturbed during cooling is currently unknown. Here, to quantify the effects of cooling, we combined continuum model calculations of the temperature drop, molecular dynamics simulations of a ribosome complex before and during cooling with kinetic models. Our results suggest that three effects markedly contribute to the narrowing of the structural ensembles: thermal contraction, reduced thermal motion within local potential wells, and the equilibration into lower free-energy conformations by overcoming separating free-energy barriers. During cooling, barrier heights below 10 kJ/mol were found to be overcome, which is expected to reduce B-factors in ensembles imaged by cryo-EM. Our approach now enables the quantification of the heterogeneity of room-temperature ensembles from cryo-EM structures. The rapid temperature drop during plunge-freezing affects the structural ensembles obtained by cryo-EM. To quantify the extent of perturbation, Bock and Grubmüller combined continuum calculations, MD simulations, and kinetic models.
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Affiliation(s)
- Lars V Bock
- Theoretical and Computational Biophysics Department, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.
| | - Helmut Grubmüller
- Theoretical and Computational Biophysics Department, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
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42
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Budiardjo SJ, Stevens JJ, Calkins AL, Ikujuni AP, Wimalasena VK, Firlar E, Case DA, Biteen JS, Kaelber JT, Slusky JSG. Colicin E1 opens its hinge to plug TolC. eLife 2022; 11:73297. [PMID: 35199644 PMCID: PMC9020818 DOI: 10.7554/elife.73297] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 02/21/2022] [Indexed: 12/02/2022] Open
Abstract
The double membrane architecture of Gram-negative bacteria forms a barrier that is impermeable to most extracellular threats. Bacteriocin proteins evolved to exploit the accessible, surface-exposed proteins embedded in the outer membrane to deliver cytotoxic cargo. Colicin E1 is a bacteriocin produced by, and lethal to, Escherichia coli that hijacks the outer membrane proteins (OMPs) TolC and BtuB to enter the cell. Here, we capture the colicin E1 translocation domain inside its membrane receptor, TolC, by high-resolution cryo-electron microscopy to obtain the first reported structure of a bacteriocin bound to TolC. Colicin E1 binds stably to TolC as an open hinge through the TolC pore—an architectural rearrangement from colicin E1’s unbound conformation. This binding is stable in live E. coli cells as indicated by single-molecule fluorescence microscopy. Finally, colicin E1 fragments binding to TolC plug the channel, inhibiting its native efflux function as an antibiotic efflux pump, and heightening susceptibility to three antibiotic classes. In addition to demonstrating that these protein fragments are useful starting points for developing novel antibiotic potentiators, this method could be expanded to other colicins to inhibit other OMP functions. Bacteria are constantly warring with each other for space and resources. As a result, they have developed a range of molecular weapons to poison, damage or disable other cells. For instance, bacteriocins are proteins that can latch onto structures at the surface of enemy bacteria and push toxins through their outer membrane. Bacteria are increasingly resistant to antibiotics, representing a growing concern for modern healthcare. One way that they are able to survive is by using ‘efflux pumps’ studded through their external membranes to expel harmful drugs before these can cause damage. Budiardjo et al. wanted to test whether bacteriocins could interfere with this defence mechanism by blocking efflux pumps. Bacteriocins are usually formed of binding elements (which recognise specific target proteins) and of a ‘killer tail’ that can stab the cell. Experiments showed that the binding parts of a bacteriocin could effectively ‘plug’ efflux pumps in Escherichia coli bacteria: high-resolution molecular microscopy revealed how the bacteriocin fragment binds to the pump, while fluorescent markers showed that it attached to the surface of E. coli and stopped the efflux pumps from working. As a result, lower amounts of antibiotics were necessary to kill the bacteria when bacteriocins were present. The work by Budiardjo et al. could lead to new ways to combat bacteria that will reduce the need for current antibiotics. In the future, bacteriocins could also be harnessed to target other proteins than efflux pumps, allowing scientists to manipulate a range of bacterial processes.
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Affiliation(s)
- S Jimmy Budiardjo
- Center for Computational Biology, University of Kansas, Lawrence, United States
| | - Jacqueline J Stevens
- Department of Molecular Biosciences, University of Kansas, Lawrence, United States
| | - Anna L Calkins
- Department of Chemistry, University of Michigan, Ann Arbor, United States
| | - Ayotunde P Ikujuni
- Department of Molecular Biosciences, University of Kansas, Lawrence, United States
| | | | - Emre Firlar
- Institute for Quantitative Biomedicine, Rutgers University, Piscataway, United States
| | - David A Case
- Institute for Quantitative Biomedicine, Rutgers University, Piscataway, United States
| | - Julie S Biteen
- Department of Chemistry, University of Michigan, Ann Arbor, United States
| | - Jason T Kaelber
- Institute for Quantitative Biomedicine, Rutgers, The State University of New Jersey, Piscataway, United States
| | - Joanna S G Slusky
- Center for Computational Biology, University of Kansas, Lawrence, United States
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43
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Foster HE, Ventura Santos C, Carter AP. A cryo-ET survey of microtubules and intracellular compartments in mammalian axons. J Cell Biol 2022; 221:e202103154. [PMID: 34878519 PMCID: PMC7612188 DOI: 10.1083/jcb.202103154] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 09/28/2021] [Accepted: 11/16/2021] [Indexed: 12/16/2022] Open
Abstract
The neuronal axon is packed with cytoskeletal filaments, membranes, and organelles, many of which move between the cell body and axon tip. Here, we used cryo-electron tomography to survey the internal components of mammalian sensory axons. We determined the polarity of the axonal microtubules (MTs) by combining subtomogram classification and visual inspection, finding MT plus and minus ends are structurally similar. Subtomogram averaging of globular densities in the MT lumen suggests they have a defined structure, which is surprising given they likely contain the disordered protein MAP6. We found the endoplasmic reticulum in axons is tethered to MTs through multiple short linkers. We surveyed membrane-bound cargos and describe unexpected internal features such as granules and broken membranes. In addition, we detected proteinaceous compartments, including numerous virus-like capsid particles. Our observations outline novel features of axonal cargos and MTs, providing a platform for identification of their constituents.
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44
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Zimanyi CM, Kopylov M, Potter CS, Carragher B, Eng ET. Broadening access to cryoEM through centralized facilities. Trends Biochem Sci 2022; 47:106-116. [PMID: 34823974 PMCID: PMC8760164 DOI: 10.1016/j.tibs.2021.10.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 10/22/2021] [Accepted: 10/26/2021] [Indexed: 02/03/2023]
Abstract
Cryogenic electron microscopy (cryoEM) uses images of frozen hydrated biological specimens to produce macromolecular structures, opening up previously inaccessible levels of biological organization to high-resolution structural analysis. CryoEM has the potential for broad impact in biomedical research, including basic cell, molecular, and structural biology, and increasingly in drug discovery and vaccine development. Recent advances have led to the expansion of molecular and cellular structure determination at an exponential rate. National and regional centers have emerged to support this growth by increasing the accessibility of cryoEM throughout the biomedical research community. Through cooperation and synergy, these centers form a network of resources that accelerate the adoption of best practices for access and training and establish sustainable workflows to build future research capacity.
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Affiliation(s)
- Christina M. Zimanyi
- Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, USA
| | - Mykhailo Kopylov
- Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, USA
| | - Clinton S. Potter
- Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, USA,Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Bridget Carragher
- Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, USA,Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Edward T. Eng
- Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, USA,Correspondence: (E.T. Eng)
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45
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Klumpe S, Fung HKH, Goetz SK, Zagoriy I, Hampoelz B, Zhang X, Erdmann PS, Baumbach J, Müller CW, Beck M, Plitzko JM, Mahamid J. A modular platform for automated cryo-FIB workflows. eLife 2021; 10:e70506. [PMID: 34951584 PMCID: PMC8769651 DOI: 10.7554/elife.70506] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 12/23/2021] [Indexed: 11/22/2022] Open
Abstract
Lamella micromachining by focused ion beam milling at cryogenic temperature (cryo-FIB) has matured into a preparation method widely used for cellular cryo-electron tomography. Due to the limited ablation rates of low Ga+ ion beam currents required to maintain the structural integrity of vitreous specimens, common preparation protocols are time-consuming and labor intensive. The improved stability of new-generation cryo-FIB instruments now enables automated operations. Here, we present an open-source software tool, SerialFIB, for creating automated and customizable cryo-FIB preparation protocols. The software encompasses a graphical user interface for easy execution of routine lamellae preparations, a scripting module compatible with available Python packages, and interfaces with three-dimensional correlative light and electron microscopy (CLEM) tools. SerialFIB enables the streamlining of advanced cryo-FIB protocols such as multi-modal imaging, CLEM-guided lamella preparation and in situ lamella lift-out procedures. Our software therefore provides a foundation for further development of advanced cryogenic imaging and sample preparation protocols.
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Affiliation(s)
- Sven Klumpe
- Department Molecular Structural Biology, Max Planck Institute of BiochemistryMartinsriedGermany
| | - Herman KH Fung
- Structural and Computational Biology Unit, European Molecular Biology LaboratoryHeidelbergGermany
| | - Sara K Goetz
- Structural and Computational Biology Unit, European Molecular Biology LaboratoryHeidelbergGermany
- Collaboration for joint PhD degree between EMBL and Heidelberg University, Faculty of BiosciencesHeidelbergGermany
| | - Ievgeniia Zagoriy
- Structural and Computational Biology Unit, European Molecular Biology LaboratoryHeidelbergGermany
| | - Bernhard Hampoelz
- Structural and Computational Biology Unit, European Molecular Biology LaboratoryHeidelbergGermany
| | - Xiaojie Zhang
- Structural and Computational Biology Unit, European Molecular Biology LaboratoryHeidelbergGermany
| | - Philipp S Erdmann
- Department Molecular Structural Biology, Max Planck Institute of BiochemistryMartinsriedGermany
| | - Janina Baumbach
- Structural and Computational Biology Unit, European Molecular Biology LaboratoryHeidelbergGermany
| | - Christoph W Müller
- Structural and Computational Biology Unit, European Molecular Biology LaboratoryHeidelbergGermany
| | - Martin Beck
- Structural and Computational Biology Unit, European Molecular Biology LaboratoryHeidelbergGermany
- Cell Biology and Biophysics Unit, European Molecular Biology LaboratoryHeidelbergGermany
| | - Jürgen M Plitzko
- Department Molecular Structural Biology, Max Planck Institute of BiochemistryMartinsriedGermany
| | - Julia Mahamid
- Structural and Computational Biology Unit, European Molecular Biology LaboratoryHeidelbergGermany
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46
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A cryo-TSEM with temperature cycling capability allows deep sublimation of ice to uncover fine structures in thick cells. Sci Rep 2021; 11:21406. [PMID: 34725450 PMCID: PMC8560947 DOI: 10.1038/s41598-021-00979-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 10/18/2021] [Indexed: 11/08/2022] Open
Abstract
The scanning electron microscope (SEM) has been reassembled into a new type of cryo-electron microscope (cryo-TSEM) by installing a new cryo-transfer holder and anti-contamination trap, which allowed simultaneous acquisition of both transmission images (STEM images) and surface images (SEM images) in the frozen state. The ultimate temperatures of the holder and the trap reached − 190 °C and − 210 °C, respectively, by applying a liquid nitrogen slush. The STEM images at 30 kV were comparable to, or superior to, the images acquired with conventional transmission electron microscope (100 kV TEM) in contrast and sharpness. The unroofing method was used to observe membrane cytoskeletons instead of the frozen section and the FIB methods. Deep sublimation of ice surrounding unroofed cells by regulating temperature enabled to emerge intracellular fine structures in thick frozen cells. Hence, fine structures in the vicinity of the cell membrane such as the cytoskeleton, polyribosome chains and endoplasmic reticulum (ER) became visible. The ER was distributed as a wide, flat structure beneath the cell membrane, forming a large spatial network with tubular ER.
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47
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Engstrom T, Clinger JA, Spoth KA, Clarke OB, Closs DS, Jayne R, Apker BA, Thorne RE. High-resolution single-particle cryo-EM of samples vitrified in boiling nitro-gen. IUCRJ 2021; 8:867-877. [PMID: 34804541 PMCID: PMC8562666 DOI: 10.1107/s2052252521008095] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 08/05/2021] [Indexed: 05/24/2023]
Abstract
Based on work by Dubochet and others in the 1980s and 1990s, samples for single-particle cryo-electron microscopy (cryo-EM) have been vitrified using ethane, propane or ethane/propane mixtures. These liquid cryogens have a large difference between their melting and boiling temperatures and so can absorb substantial heat without formation of an insulating vapor layer adjacent to a cooling sample. However, ethane and propane are flammable, they must be liquified in liquid nitro-gen immediately before cryo-EM sample preparation, and cryocooled samples must be transferred to liquid nitro-gen for storage, complicating workflows and increasing the chance of sample damage during handling. Experiments over the last 15 years have shown that cooling rates required to vitrify pure water are only ∼250 000 K s-1, at the low end of earlier estimates, and that the dominant factor that has limited cooling rates of small samples in liquid nitro-gen is sample precooling in cold gas present above the liquid cryogen surface, not the Leidenfrost effect. Using an automated cryocooling instrument developed for cryocrystallography that combines high plunge speeds with efficient removal of cold gas, we show that single-particle cryo-EM samples on commercial grids can be routinely vitrified using only boiling nitro-gen and obtain apoferritin datasets and refined structures with 2.65 Å resolution. The use of liquid nitro-gen as the primary coolant may allow manual and automated workflows to be simplified and may reduce sample stresses that contribute to beam-induced motion.
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Affiliation(s)
| | | | - Katherine A. Spoth
- Cornell Center for Materials Research, Cornell University, Ithaca, NY 14853, USA
| | - Oliver B. Clarke
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY 10032, USA
- Department of Anesthesiology, Columbia University, New York, NY 10032, USA
| | | | - Richard Jayne
- MiTeGen, LLC, PO Box 3867, Ithaca, NY 14850-3867, USA
| | | | - Robert E. Thorne
- MiTeGen, LLC, PO Box 3867, Ithaca, NY 14850-3867, USA
- Physics Department, Cornell University, Ithaca, NY 14853, USA
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48
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Kang MH, Park J, Kang S, Jeon S, Lee M, Shim JY, Lee J, Jeon TJ, Ahn MK, Lee SM, Kwon O, Kim BH, Meyerson JR, Lee MJ, Lim KI, Roh SH, Lee WC, Park J. Graphene Oxide-Supported Microwell Grids for Preparing Cryo-EM Samples with Controlled Ice Thickness. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2102991. [PMID: 34510585 DOI: 10.1002/adma.202102991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 08/11/2021] [Indexed: 06/13/2023]
Abstract
Cryogenic-electron microscopy (cryo-EM) is the preferred method to determine 3D structures of proteins and to study diverse material systems that intrinsically have radiation or air sensitivity. Current cryo-EM sample preparation methods provide limited control over the sample quality, which limits the efficiency and high throughput of 3D structure analysis. This is partly because it is difficult to control the thickness of the vitreous ice that embeds specimens, in the range of nanoscale, depending on the size and type of materials of interest. Thus, there is a need for fine regulation of the thickness of vitreous ice to deliver consistent high signal-to-noise ratios for low-contrast biological specimens. Herein, an advanced silicon-chip-based device is developed which has a regular array of micropatterned holes with a graphene oxide (GO) window on freestanding silicon nitride (Six Ny ). Accurately regulated depths of micropatterned holes enable precise control of vitreous ice thickness. Furthermore, GO window with affinity for biomolecules can facilitate concentration of the sample molecules at a higher level. Incorporation of micropatterned chips with a GO window enhances cryo-EM imaging for various nanoscale biological samples including human immunodeficiency viral particles, groEL tetradecamers, apoferritin octahedral, aldolase homotetramer complexes, and tau filaments, as well as inorganic materials.
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Affiliation(s)
- Min-Ho Kang
- School of Chemical and Biological Engineering, and Institute of Chemical Processes (ICP), Seoul National University, Seoul, 08826, Republic of Korea
- Center for Nanoparticle Research, Institute of Basic Science (IBS), Seoul, 08826, Republic of Korea
| | - Junsun Park
- School of Biological Sciences, Seoul National University, Seoul, 08826, Republic of Korea
| | - Sungsu Kang
- School of Chemical and Biological Engineering, and Institute of Chemical Processes (ICP), Seoul National University, Seoul, 08826, Republic of Korea
- Center for Nanoparticle Research, Institute of Basic Science (IBS), Seoul, 08826, Republic of Korea
| | - Sungho Jeon
- Department of Mechanical Engineering, BK21FOUR ERICA-ACE Center, Hanyang University, Ansan, Gyeonggi, 15588, Republic of Korea
| | - Minyoung Lee
- School of Chemical and Biological Engineering, and Institute of Chemical Processes (ICP), Seoul National University, Seoul, 08826, Republic of Korea
- Center for Nanoparticle Research, Institute of Basic Science (IBS), Seoul, 08826, Republic of Korea
| | - Ji-Yeon Shim
- Department of Chemical and Biological Engineering, Sookmyung Women's University, Seoul, 04310, Republic of Korea
| | - Jeeyoung Lee
- Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul, 03080, Republic of Korea
| | - Tae Jin Jeon
- National Instrumentation Center for Environmental Management, Seoul National University, Seoul, 08826, Republic of Korea
| | - Min Kyung Ahn
- Department of Materials Science and Engineering, Seoul National University, Seoul, 08826, Republic of Korea
- Biomedical Implant Convergence Research Lab, Advanced Institutes of Convergence Technology, Suwon, 16229, Republic of Korea
| | - Sung Mi Lee
- Department of Materials Science and Engineering, Seoul National University, Seoul, 08826, Republic of Korea
- Biomedical Implant Convergence Research Lab, Advanced Institutes of Convergence Technology, Suwon, 16229, Republic of Korea
| | - Ohkyung Kwon
- National Instrumentation Center for Environmental Management, Seoul National University, Seoul, 08826, Republic of Korea
| | - Byung Hyo Kim
- Department of Organic Materials and Fiber Engineering, Soongsil University, Seoul, 06978, Republic of Korea
| | - Joel R Meyerson
- Department of Physiology and Biophysics, Weill Cornell Medical College of Cornell University, New York, NY, 10065, USA
| | - Min Jae Lee
- Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul, 03080, Republic of Korea
| | - Kwang-Il Lim
- Department of Chemical and Biological Engineering, Sookmyung Women's University, Seoul, 04310, Republic of Korea
| | - Soung-Hun Roh
- School of Biological Sciences, Seoul National University, Seoul, 08826, Republic of Korea
| | - Won Chul Lee
- Department of Mechanical Engineering, BK21FOUR ERICA-ACE Center, Hanyang University, Ansan, Gyeonggi, 15588, Republic of Korea
| | - Jungwon Park
- School of Chemical and Biological Engineering, and Institute of Chemical Processes (ICP), Seoul National University, Seoul, 08826, Republic of Korea
- Center for Nanoparticle Research, Institute of Basic Science (IBS), Seoul, 08826, Republic of Korea
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49
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Danev R, Belousoff M, Liang YL, Zhang X, Eisenstein F, Wootten D, Sexton PM. Routine sub-2.5 Å cryo-EM structure determination of GPCRs. Nat Commun 2021; 12:4333. [PMID: 34267200 PMCID: PMC8282782 DOI: 10.1038/s41467-021-24650-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 06/29/2021] [Indexed: 11/24/2022] Open
Abstract
Cryo-electron microscopy (cryo-EM) of small membrane proteins, such as G protein-coupled receptors (GPCRs), remains challenging. Pushing the performance boundaries of the technique requires quantitative knowledge about the contribution of multiple factors. Here, we present an in-depth analysis and optimization of the main experimental parameters in cryo-EM. We combined actual structural studies with methods development to quantify the effects of the Volta phase plate, zero-loss energy filtering, objective lens aperture, defocus magnitude, total exposure, and grid type. By using this information to carefully maximize the experimental performance, it is now possible to routinely determine GPCR structures at resolutions better than 2.5 Å. The improved fidelity of such maps enables the building of better atomic models and will be crucial for the future expansion of cryo-EM into the structure-based drug design domain. The optimization guidelines given here are not limited to GPCRs and can be applied directly to other small proteins.
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Affiliation(s)
- Radostin Danev
- Graduate School of Medicine, University of Tokyo, Tokyo, Japan.
| | - Matthew Belousoff
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
- ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Yi-Lynn Liang
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
- Confo Therapeutics, Ghent (Zwijnaarde), Belgium
| | - Xin Zhang
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
- ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | | | - Denise Wootten
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
- ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Patrick M Sexton
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
- ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
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50
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Cater RJ, Chua GL, Erramilli SK, Keener JE, Choy BC, Tokarz P, Chin CF, Quek DQY, Kloss B, Pepe JG, Parisi G, Wong BH, Clarke OB, Marty MT, Kossiakoff AA, Khelashvili G, Silver DL, Mancia F. Structural basis of omega-3 fatty acid transport across the blood-brain barrier. Nature 2021; 595:315-319. [PMID: 34135507 PMCID: PMC8266758 DOI: 10.1038/s41586-021-03650-9] [Citation(s) in RCA: 57] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Accepted: 05/17/2021] [Indexed: 02/05/2023]
Abstract
Docosahexaenoic acid is an omega-3 fatty acid that is essential for neurological development and function, and it is supplied to the brain and eyes predominantly from dietary sources1-6. This nutrient is transported across the blood-brain and blood-retina barriers in the form of lysophosphatidylcholine by major facilitator superfamily domain containing 2A (MFSD2A) in a Na+-dependent manner7,8. Here we present the structure of MFSD2A determined using single-particle cryo-electron microscopy, which reveals twelve transmembrane helices that are separated into two pseudosymmetric domains. The transporter is in an inward-facing conformation and features a large amphipathic cavity that contains the Na+-binding site and a bound lysolipid substrate, which we confirmed using native mass spectrometry. Together with our functional analyses and molecular dynamics simulations, this structure reveals details of how MFSD2A interacts with substrates and how Na+-dependent conformational changes allow for the release of these substrates into the membrane through a lateral gate. Our work provides insights into the molecular mechanism by which this atypical major facility superfamily transporter mediates the uptake of lysolipids into the brain, and has the potential to aid in the delivery of neurotherapeutic agents.
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Affiliation(s)
- Rosemary J Cater
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA
| | - Geok Lin Chua
- Signature Research Program in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore, Singapore
| | - Satchal K Erramilli
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL, USA
| | - James E Keener
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, USA
| | - Brendon C Choy
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA
| | - Piotr Tokarz
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL, USA
| | - Cheen Fei Chin
- Signature Research Program in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore, Singapore
| | - Debra Q Y Quek
- Signature Research Program in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore, Singapore
| | - Brian Kloss
- Center on Membrane Protein Production and Analysis, New York Structural Biology Center, New York, NY, USA
| | - Joseph G Pepe
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA
| | - Giacomo Parisi
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA
| | - Bernice H Wong
- Signature Research Program in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore, Singapore
| | - Oliver B Clarke
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA
- Department of Anesthesiology, Columbia University Irving Medical Center, New York, NY, USA
| | - Michael T Marty
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, USA
| | - Anthony A Kossiakoff
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL, USA
| | - George Khelashvili
- Department of Physiology and Biophysics, Weill Cornell Medical College, Cornell University, New York, NY, USA.
- Institute for Computational Biomedicine, Weill Cornell Medical College, Cornell University, New York, NY, USA.
| | - David L Silver
- Signature Research Program in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore, Singapore.
| | - Filippo Mancia
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA.
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