201
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Gaietta G, Swift MF, Volkmann N, Hanein D. Rapid tool for cell nanoarchitecture integrity assessment. J Struct Biol 2021; 213:107801. [PMID: 34582983 PMCID: PMC8665072 DOI: 10.1016/j.jsb.2021.107801] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 09/12/2021] [Accepted: 09/21/2021] [Indexed: 12/13/2022]
Abstract
With the rapid increase and accessibility of high-resolution imaging technologies of cells, the interpretation of results relies more and more on the assumption that the three-dimensional integrity of the surrounding cellular landscape is not compromised by the experimental setup. However, the only available technology for directly probing the structural integrity of whole-cell preparations at the nanoscale is electron cryo-tomography, which is time-consuming, costly, and complex. We devised an accessible, inexpensive and reliable screening assay to quickly report on the compatibility of experimental protocols with preserving the structural integrity of whole-cell preparations at the nanoscale. Our Rapid Cell Integrity Assessment (RCIA) assay is executed at room temperature and relies solely on light microscopy imaging. Using cellular electron cryo-tomography as a benchmark, we verify that RCIA accurately unveils the adverse impact of reagents and/or protocols such as those used for virus inactivation or to arrest dynamic processes on the cellular nanoarchitecture.
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Affiliation(s)
| | | | - Niels Volkmann
- Scintillon Institute, San Diego CA 92123, USA; Institut Pasteur, Université de Paris, CNRS UMR3528, Structural Image Analysis Unit, F-75015 Paris, France
| | - Dorit Hanein
- Scintillon Institute, San Diego CA 92123, USA; Institut Pasteur, CNRS UMR3528, Structural Studies of Macromolecular Machines in Cellulo Unit, F-75015 Paris, France.
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202
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Harastani M, Eltsov M, Leforestier A, Jonic S. TomoFlow: Analysis of Continuous Conformational Variability of Macromolecules in Cryogenic Subtomograms based on 3D Dense Optical Flow. J Mol Biol 2021; 434:167381. [PMID: 34848215 DOI: 10.1016/j.jmb.2021.167381] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 11/21/2021] [Accepted: 11/22/2021] [Indexed: 01/14/2023]
Abstract
Cryogenic Electron Tomography (cryo-ET) allows structural and dynamics studies of macromolecules in situ. Averaging different copies of imaged macromolecules is commonly used to obtain their structure at higher resolution and discrete classification to analyze their dynamics. Instrumental and data processing developments are progressively equipping cryo-ET studies with the ability to escape the trap of classification into a complete continuous conformational variability analysis. In this work, we propose TomoFlow, a method for analyzing macromolecular continuous conformational variability in cryo-ET subtomograms based on a three-dimensional dense optical flow (OF) approach. The resultant lower-dimensional conformational space allows generating movies of macromolecular motion and obtaining subtomogram averages by grouping conformationally similar subtomograms. The animations and the subtomogram group averages reveal accurate trajectories of macromolecular motion based on a novel mathematical model that makes use of OF properties. This paper describes TomoFlow with tests on simulated datasets generated using different techniques, namely Normal Mode Analysis and Molecular Dynamics Simulation. It also shows an application of TomoFlow on a dataset of nucleosomes in situ, which provided promising results coherent with previous findings using the same dataset but without imposing any prior knowledge on the analysis of the conformational variability. The method is discussed with its potential uses and limitations.
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Affiliation(s)
- Mohamad Harastani
- IMPMC - UMR 7590 CNRS, Sorbonne Université, Muséum National d'Histoire Naturelle, Paris, France; Laboratoire de Physique des Solides (LPS), UMR 8502 CNRS, Université Paris-Saclay, Orsay, France. https://twitter.com/moh_harastani
| | - Mikhail Eltsov
- Department of Integrated Structural Biology, Institute of Genetics and Molecular and Cellular Biology, Illkirch, France. https://twitter.com/EltsovMikhail
| | - Amélie Leforestier
- Laboratoire de Physique des Solides (LPS), UMR 8502 CNRS, Université Paris-Saclay, Orsay, France
| | - Slavica Jonic
- IMPMC - UMR 7590 CNRS, Sorbonne Université, Muséum National d'Histoire Naturelle, Paris, France.
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203
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Frangakis AS. It's noisy out there! A review of denoising techniques in cryo-electron tomography. J Struct Biol 2021; 213:107804. [PMID: 34732363 DOI: 10.1016/j.jsb.2021.107804] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 10/14/2021] [Accepted: 10/19/2021] [Indexed: 11/16/2022]
Abstract
Cryo-electron tomography is the only technique that can provide sub-nanometer resolved images of cell regions or even whole cells, without the need of labeling or staining methods. Technological advances over the past decade in electron microscope stability, cameras, stage precision and software have resulted in faster acquisition speeds and considerably improved resolution. In pursuit of even better image resolution, researchers seek to reduce noise - a crucial factor affecting the reliability of the tomogram interpretation and ultimately limiting the achieved resolution. Sub-tomogram averaging is the method of choice for reducing noise in repetitive objects. However, when averaging is not applicable, a trade-off between reducing noise and conserving genuine image details must be achieved. Thus, denoising is an important process that improves the interpretability of the tomogram not only directly but also by facilitating other downstream tasks, such as segmentation and 3D visualization. Here, I review contemporary denoising techniques for cryo-electron tomography by taking into account noise-specific properties of both reconstruction and detector noise. The outcomes of different techniques are compared, in order to help researchers select the most appropriate for each dataset and to achieve better and more reliable interpretation of the tomograms.
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Affiliation(s)
- Achilleas S Frangakis
- Buchmann Institute for Molecular Life Sciences and Institute for Biophysics, Goethe University Frankfurt Max-von-Laue-Str. 15, Frankfurt am Main, D-60438, Germany.
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204
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Conquer by cryo-EM without physically dividing. Biochem Soc Trans 2021; 49:2287-2298. [PMID: 34709401 DOI: 10.1042/bst20210360] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 09/29/2021] [Accepted: 10/05/2021] [Indexed: 12/15/2022]
Abstract
This mini-review provides an update regarding the substantial progress that has been made in using single-particle cryo-EM to obtain high-resolution structures for proteins and other macromolecules whose particle sizes are smaller than 100 kDa. We point out that establishing the limits of what can be accomplished, both in terms of particle size and attainable resolution, serves as a guide for what might be expected when attempting to improve the resolution of small flexible portions of a larger structure using focused refinement approaches. These approaches, which involve computationally ignoring all but a specific, targeted region of interest on the macromolecules, is known as 'masking and refining,' and it thus is the computational equivalent of the 'divide and conquer' approach that has been used so successfully in X-ray crystallography. The benefit of masked refinement, however, is that one is able to determine structures in their native architectural context, without physically separating them from the biological connections that they require for their function. This mini-review also compares where experimental achievements currently stand relative to various theoretical estimates for the smallest particle size that can be successfully reconstructed to high resolution. Since it is clear that a substantial gap still remains between the two, we briefly recap the areas in which further improvement seems possible, both in equipment and in methods.
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205
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Studying bacterial chemosensory array with CryoEM. Biochem Soc Trans 2021; 49:2081-2089. [PMID: 34495335 PMCID: PMC8589424 DOI: 10.1042/bst20210080] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 08/16/2021] [Accepted: 08/19/2021] [Indexed: 12/30/2022]
Abstract
Bacteria direct their movement in respond to gradients of nutrients and other stimuli in the environment through the chemosensory system. The behavior is mediated by chemosensory arrays that are made up of thousands of proteins to form an organized array near the cell pole. In this review, we briefly introduce the architecture and function of the chemosensory array and its core signaling unit. We describe the in vivo and in vitro systems that have been used for structural studies of chemosensory array by cryoEM, including reconstituted lipid nanodiscs, 2D lipid monolayer arrays, lysed bacterial ghosts, bacterial minicells and native bacteria cells. Lastly, we review recent advances in structural analysis of chemosensory arrays using state-of-the-art cryoEM and cryoET methodologies, focusing on the latest developments and insights with a perspective on current challenges and future directions.
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206
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207
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Hoffmann PC, Giandomenico SL, Ganeva I, Wozny MR, Sutcliffe M, Lancaster MA, Kukulski W. Electron cryo-tomography reveals the subcellular architecture of growing axons in human brain organoids. eLife 2021; 10:e70269. [PMID: 34698018 PMCID: PMC8547956 DOI: 10.7554/elife.70269] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 10/08/2021] [Indexed: 12/17/2022] Open
Abstract
During brain development, axons must extend over great distances in a relatively short amount of time. How the subcellular architecture of the growing axon sustains the requirements for such rapid build-up of cellular constituents has remained elusive. Human axons have been particularly poorly accessible to imaging at high resolution in a near-native context. Here, we present a method that combines cryo-correlative light microscopy and electron tomography with human cerebral organoid technology to visualize growing axon tracts. Our data reveal a wealth of structural details on the arrangement of macromolecules, cytoskeletal components, and organelles in elongating axon shafts. In particular, the intricate shape of the endoplasmic reticulum is consistent with its role in fulfilling the high demand for lipid biosynthesis to support growth. Furthermore, the scarcity of ribosomes within the growing shaft suggests limited translational competence during expansion of this compartment. These findings establish our approach as a powerful resource for investigating the ultrastructure of defined neuronal compartments.
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Affiliation(s)
- Patrick C Hoffmann
- MRC Laboratory of Molecular Biology, Francis Crick AvenueCambridgeUnited Kingdom
| | | | - Iva Ganeva
- MRC Laboratory of Molecular Biology, Francis Crick AvenueCambridgeUnited Kingdom
| | - Michael R Wozny
- MRC Laboratory of Molecular Biology, Francis Crick AvenueCambridgeUnited Kingdom
| | - Magdalena Sutcliffe
- MRC Laboratory of Molecular Biology, Francis Crick AvenueCambridgeUnited Kingdom
| | - Madeline A Lancaster
- MRC Laboratory of Molecular Biology, Francis Crick AvenueCambridgeUnited Kingdom
| | - Wanda Kukulski
- MRC Laboratory of Molecular Biology, Francis Crick AvenueCambridgeUnited Kingdom
- Institute of Biochemistry and Molecular Medicine, University of BernBernSwitzerland
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208
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Hurst PJ, Morris MA, Graham AA, Nowick JS, Patterson JP. Visualizing Teixobactin Supramolecular Assemblies and Cell Wall Damage in B. Subtilis Using CryoEM. ACS OMEGA 2021; 6:27412-27417. [PMID: 34693162 PMCID: PMC8529686 DOI: 10.1021/acsomega.1c04331] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 09/24/2021] [Indexed: 05/04/2023]
Abstract
The antibiotic teixobactin targets bacterial cell walls. Previous research has proposed that the active form of teixobactin is a nano-/micron-sized supramolecular assembly. Here, we use cryogenic transmission electron microscopy to show that at 1 mg/mL, teixobactin forms sheet-like assemblies that selectively act upon the cell wall. At 4 μg/mL, teixobactin is active, and aggregates are formed either transiently or sparingly at the cell surface.
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Affiliation(s)
- Paul Joshua Hurst
- Department
of Chemistry, University of California—Irvine, Irvine, California 92697-2025, United States
| | - Michael A. Morris
- Department
of Chemistry, University of California—Irvine, Irvine, California 92697-2025, United States
| | - Annissa A. Graham
- Department
of Chemistry, University of California—Irvine, Irvine, California 92697-2025, United States
| | - James S. Nowick
- Department
of Chemistry, University of California—Irvine, Irvine, California 92697-2025, United States
| | - Joseph P. Patterson
- Department
of Chemistry, University of California—Irvine, Irvine, California 92697-2025, United States
- Department
of Materials Science and Engineering, University
of California, Irvine, California 92697, United States
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209
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Shepherd DC, Dalvi S, Ghosal D. From cells to atoms: Cryo-EM as an essential tool to investigate pathogen biology, host-pathogen interaction, and drug discovery. Mol Microbiol 2021; 117:610-617. [PMID: 34592048 DOI: 10.1111/mmi.14820] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Accepted: 09/23/2021] [Indexed: 01/18/2023]
Abstract
Electron cryo-microscopy (cryo-EM) has lately emerged as a powerful method in structural biology and cell biology. While cryo-EM single-particle analysis (SPA) is now routinely delivering structures of purified proteins and protein complexes at near-atomic resolution, the use of electron cryo-tomography (cryo-ET), together with subtomogram averaging, is allowing visualization of macromolecular complexes in their native cellular environment, at unprecedented resolution. The unique ability of cryo-EM to provide information at many spatial resolution scales from ångströms to microns makes it an invaluable tool that bridges the classic "resolution-gap" between structural biology and cell biology domains. Like in many other fields of biology, in recent years, cryo-EM has revolutionized our understanding of pathogen biology, host-pathogen interaction and has made significant strides toward structure-based drug discovery. In a very recent example, during the ongoing coronavirus disease (COVID-19) pandemic, the structure of the stabilized severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein was deciphered by SPA. This led to the development of multiple vaccines. Alongside, cryo-ET provided key insights into the structure of the native virion, mechanism of its entry, replication, and budding; demonstrating the unrivaled power of cryo-EM in investigating pathogen biology, host-pathogen interaction, and drug discovery. In this review, we showcase a few examples of how different imaging modalities within cryo-EM have enabled the study of microbiology and host-pathogen interaction.
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Affiliation(s)
- Doulin C Shepherd
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia
| | - Somavally Dalvi
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia
| | - Debnath Ghosal
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia
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210
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Klaholz BP. Studying the Structural Organization of Polyribosomes with Alexander S. Spirin. BIOCHEMISTRY (MOSCOW) 2021; 86:1053-1059. [PMID: 34565311 DOI: 10.1134/s0006297921090030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
"Would it be possible to analyze molecular mechanisms and structural organisation of polyribosome assemblies using cryo electron tomography?" - we asked through a longstanding collaboration between my research group and that of Alexander S. Spirin. Indeed, it was: we found that double-row polyribosomes can have both circular and linear arrangements of their mRNA [Afonina, Z. A., et al. (2013) Biochemistry (Moscow)], we figured out how eukaryotic ribosomes assemble on an mRNA to form supramolecular left-handed helices [Myasnikov, A. G., et al. (2014) Nat. Commun.], that the circularization of polyribosomes is poly-A and cap-independent [Afonina, Z. A., et al. (2014) Nucleic Acids Res.], and that intermediary polyribosomes with open structures exist after a transition from a juvenile phase to strongly translating polysomes of medium size [Afonina, Z. A., et al. (2015) Nucleic Acids Res.] until they form densely packed helical structures with reduced activity. Our joint fruitful exchanges, hence, led to major advances in the field, which are reviewed here from a personal and historical perspective in memory of Alexander S. Spirin.
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Affiliation(s)
- Bruno P Klaholz
- Centre for Integrative Biology (CBI), Department of Integrated Structural Biology, IGBMC (Institute of Genetics and of Molecular and Cellular Biology), Illkirch, 67404, France. .,Centre National de la Recherche Scientifique (CNRS) UMR 7104, Illkirch, 67404, France.,Institut National de la Santé et de la Recherche Médicale (INSERM) U964, Illkirch, 67404, France.,Université de Strasbourg, Strasbourg, 67081, France
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211
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Li S. Cryo-electron tomography of enveloped viruses. Trends Biochem Sci 2021; 47:173-186. [PMID: 34511334 DOI: 10.1016/j.tibs.2021.08.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 08/12/2021] [Accepted: 08/18/2021] [Indexed: 10/20/2022]
Abstract
Viruses are macromolecular machineries that hijack cellular metabolism for replication. Enveloped viruses comprise a large variety of RNA and DNA viruses, many of which are notorious human or animal pathogens. Despite their importance, the presence of lipid bilayers in their assembly has made most enveloped viruses too pleomorphic to be reconstructed as a whole by traditional structural biology methods. Furthermore, structural biology of the viral lifecycle was hindered by the sample thickness. Here, I review the recent advances in the applications of cryo-electron tomography (cryo-ET) on enveloped viral structures and intracellular viral activities.
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Affiliation(s)
- Sai Li
- School of Life Sciences, Tsinghua University, Beijing 100084, China; Beijing Advanced Innovation Center for Structural Biology and Frontier Research Center for Biological Structure, Tsinghua University, Beijing 100084, China; Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing 100084, China.
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212
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Burton-Smith RN, Murata K. Cryo-Electron Microscopy of the Giant Viruses. Microscopy (Oxf) 2021; 70:477-486. [PMID: 34490462 DOI: 10.1093/jmicro/dfab036] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 08/26/2021] [Accepted: 08/30/2021] [Indexed: 11/12/2022] Open
Abstract
High resolution study of the giant viruses presents one of the latest challenges in cryo-electron microscopy of viruses. Too small for light microscopy, but too large for easy study at high resolution by electron microscopy, they range in size from ~0.2-2 μm, from high symmetry icosahedral viruses such as Paramecium burseria Chlorella virus 1 to asymmetric forms like Tupanvirus or Pithovirus. To attain high resolution, two strategies exist to study these large viruses by cryo-EM: firstly, increasing the acceleration voltage of the electron microscope to improve sample penetration and overcome the limitations imposed by electro-optical physics at lower voltages, and secondly the method of "block-based reconstruction" pioneered by Michael G. Rossmann and his collaborators, which resolves the latter limitation through an elegant leveraging of high symmetry, but cannot overcome sample penetration limitations. In addition, more recent advances in both computational capacity and image processing also yield assistance in studying the giant viruses. Especially, the inclusion of Ewald sphere correction can provide large improvements in attainable resolutions for 300 kV electron microscopes. Despite this, the study of giant viruses remains a significant challenge.
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Affiliation(s)
- Raymond N Burton-Smith
- Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, Okazaki, Aichi, Japan.,National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki, Aichi, Japan
| | - Kazuyoshi Murata
- Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, Okazaki, Aichi, Japan.,National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki, Aichi, Japan.,Department of Physiological Sciences, School of Life Science, The Graduate University for Advanced Studies (SOKENDAI), Okazaki, Aichi, Japan
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213
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Scaramuzza S, Castaño-Díez D. Step-by-step guide to efficient subtomogram averaging of virus-like particles with Dynamo. PLoS Biol 2021; 19:e3001318. [PMID: 34437529 PMCID: PMC8389376 DOI: 10.1371/journal.pbio.3001318] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 06/09/2021] [Indexed: 11/19/2022] Open
Abstract
Subtomogram averaging (STA) is a powerful image processing technique in electron tomography used to determine the 3D structure of macromolecular complexes in their native environments. It is a fast growing technique with increasing importance in structural biology. The computational aspect of STA is very complex and depends on a large number of variables. We noticed a lack of detailed guides for STA processing. Also, current publications in this field often lack a documentation that is practical enough to reproduce the results with reasonable effort, which is necessary for the scientific community to grow. We therefore provide a complete, detailed, and fully reproducible processing protocol that covers all aspects of particle picking and particle alignment in STA. The command line-based workflow is fully based on the popular Dynamo software for STA. Within this workflow, we also demonstrate how large parts of the processing pipeline can be streamlined and automatized for increased throughput. This protocol is aimed at users on all levels. It can be used for training purposes, or it can serve as basis to design user-specific projects by taking advantage of the flexibility of Dynamo by modifying and expanding the given pipeline. The protocol is successfully validated using the Electron Microscopy Public Image Archive (EMPIAR) database entry 10164 from immature HIV-1 virus-like particles (VLPs) that describe a geometry often seen in electron tomography.
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214
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Dendooven T, Paris G, Shkumatov AV, Islam MS, Burt A, Kubańska MA, Yang TY, Hardwick SW, Luisi BF. Multi-scale ensemble properties of the Escherichia coli RNA degradosome. Mol Microbiol 2021; 117:102-120. [PMID: 34415624 PMCID: PMC7613265 DOI: 10.1111/mmi.14800] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 08/09/2021] [Accepted: 08/18/2021] [Indexed: 11/30/2022]
Abstract
In organisms from all domains of life, multi-enzyme assemblies play central roles in defining transcript lifetimes and facilitating RNA-mediated regulation of gene expression. An assembly dedicated to such roles, known as the RNA degradosome, is found amongst bacteria from highly diverse lineages. About a fifth of the assembly mass of the degradosome of Escherichia coli and related species is predicted to be intrinsically disordered - a property that has been sustained for over a billion years of bacterial molecular history and stands in marked contrast to the high degree of sequence variation of that same region. Here, we characterize the conformational dynamics of the degradosome using a hybrid structural biology approach that combines solution scattering with ad hoc ensemble modelling, cryo-electron microscopy, and other biophysical methods. The E. coli degradosome can form punctate bodies in vivo that may facilitate its functional activities, and based on our results, we propose an electrostatic switch model to account for the propensity of the degradosome to undergo programmable puncta formation.
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Affiliation(s)
- Tom Dendooven
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Giulia Paris
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Alexander V Shkumatov
- Center for Structural Biology, Vlaams Instituut voor Biotechnologie, Brussels, Belgium.,Structural Biology Brussels, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Md Saiful Islam
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Alister Burt
- Institut de Biologie Structurale, Université Grenoble Alpes, CEA, CNRS, IBS, Grenoble, France
| | - Marta A Kubańska
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Tai Yuchen Yang
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | | | - Ben F Luisi
- Department of Biochemistry, University of Cambridge, Cambridge, UK
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215
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TomoAlign: A novel approach to correcting sample motion and 3D CTF in CryoET. J Struct Biol 2021; 213:107778. [PMID: 34416376 DOI: 10.1016/j.jsb.2021.107778] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 07/16/2021] [Accepted: 08/08/2021] [Indexed: 11/23/2022]
Abstract
TomoAlign is a software package that integrates tools to mitigate two important resolution limiting factors in cryoET, namely the beam-induced sample motion and the contrast transfer function (CTF) of the microscope. The package is especially focused on cryoET of thick specimens where fiducial markers are required for accurate tilt-series alignment and sample motion estimation. TomoAlign models the beam-induced sample motion undergone during the tilt-series acquisition. The motion models are used to produce motion-corrected subtilt-series centered on the particles of interest. In addition, the defocus of each particle at each tilt image is determined and can be corrected, resulting in motion-corrected and CTF-corrected subtilt-series from which the subtomograms can be computed. Alternatively, the CTF information can be passed on so that CTF correction can be carried out entirely within external packages like Relion. TomoAlign serves as a versatile tool that can streamline the cryoET workflow from initial alignment of tilt-series to final subtomogram averaging during in situ structure determination.
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216
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Phillips P, Parkhurst JM, Kounatidis I, Okolo C, Fish TM, Naismith JH, Walsh MA, Harkiolaki M, Dumoux M. Single Cell Cryo-Soft X-ray Tomography Shows That Each Chlamydia Trachomatis Inclusion Is a Unique Community of Bacteria. Life (Basel) 2021; 11:life11080842. [PMID: 34440586 PMCID: PMC8399160 DOI: 10.3390/life11080842] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 08/07/2021] [Accepted: 08/12/2021] [Indexed: 12/24/2022] Open
Abstract
Chlamydiae are strict intracellular pathogens residing within a specialised membrane-bound compartment called the inclusion. Therefore, each infected cell can, be considered as a single entity where bacteria form a community within the inclusion. It remains unclear as to how the population of bacteria within the inclusion influences individual bacterium. The life cycle of Chlamydia involves transitioning between the invasive elementary bodies (EBs) and replicative reticulate bodies (RBs). We have used cryo-soft X-ray tomography to observe individual inclusions, an approach that combines 40 nm spatial resolution and large volume imaging (up to 16 µm). Using semi-automated segmentation pipeline, we considered each inclusion as an individual bacterial niche. Within each inclusion, we identifyed and classified different forms of the bacteria and confirmed the recent finding that RBs have a variety of volumes (small, large and abnormal). We demonstrate that the proportions of these different RB forms depend on the bacterial concentration in the inclusion. We conclude that each inclusion operates as an autonomous community that influences the characteristics of individual bacteria within the inclusion.
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Affiliation(s)
- Patrick Phillips
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, UK; (P.P.); (J.M.P.); (I.K.); (C.O.); (T.M.F.); (M.A.W.); (M.H.)
- Research Complex at Harwell, Harwell Science and Innovation Campus, Didcot OX11 0DE, UK;
- Division of Structural Biology Department, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - James M. Parkhurst
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, UK; (P.P.); (J.M.P.); (I.K.); (C.O.); (T.M.F.); (M.A.W.); (M.H.)
- The Rosalind Franklin Institute, Harwell Science and Innovation Campus, Fermi Road, Didcot OX11 0FA, UK
| | - Ilias Kounatidis
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, UK; (P.P.); (J.M.P.); (I.K.); (C.O.); (T.M.F.); (M.A.W.); (M.H.)
| | - Chidinma Okolo
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, UK; (P.P.); (J.M.P.); (I.K.); (C.O.); (T.M.F.); (M.A.W.); (M.H.)
| | - Thomas M. Fish
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, UK; (P.P.); (J.M.P.); (I.K.); (C.O.); (T.M.F.); (M.A.W.); (M.H.)
| | - James H. Naismith
- Research Complex at Harwell, Harwell Science and Innovation Campus, Didcot OX11 0DE, UK;
- The Rosalind Franklin Institute, Harwell Science and Innovation Campus, Fermi Road, Didcot OX11 0FA, UK
| | - Martin A. Walsh
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, UK; (P.P.); (J.M.P.); (I.K.); (C.O.); (T.M.F.); (M.A.W.); (M.H.)
- Research Complex at Harwell, Harwell Science and Innovation Campus, Didcot OX11 0DE, UK;
| | - Maria Harkiolaki
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, UK; (P.P.); (J.M.P.); (I.K.); (C.O.); (T.M.F.); (M.A.W.); (M.H.)
- Research Complex at Harwell, Harwell Science and Innovation Campus, Didcot OX11 0DE, UK;
| | - Maud Dumoux
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, UK; (P.P.); (J.M.P.); (I.K.); (C.O.); (T.M.F.); (M.A.W.); (M.H.)
- Research Complex at Harwell, Harwell Science and Innovation Campus, Didcot OX11 0DE, UK;
- The Rosalind Franklin Institute, Harwell Science and Innovation Campus, Fermi Road, Didcot OX11 0FA, UK
- Correspondence:
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217
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Affiliation(s)
- Patrick Cramer
- Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany.
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218
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Bäuerlein FJB, Baumeister W. Towards Visual Proteomics at High Resolution. J Mol Biol 2021; 433:167187. [PMID: 34384780 DOI: 10.1016/j.jmb.2021.167187] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 08/02/2021] [Accepted: 08/02/2021] [Indexed: 11/24/2022]
Abstract
Traditionally, structural biologists approach the complexity of cellular proteomes in a reductionist manner. Proteomes are fractionated, their molecular components purified and studied one-by-one using the experimental methods for structure determination at their disposal. Visual proteomics aims at obtaining a holistic picture of cellular proteomes by studying them in situ, ideally in unperturbed cellular environments. The method that enables doing this at highest resolution is cryo-electron tomography. It allows to visualize cellular landscapes with molecular resolution generating maps or atlases revealing the interaction networks which underlie cellular functions in health and in disease states. Current implementations of cryo ET do not yet realize the full potential of the method in terms of resolution and interpretability. To this end, further improvements in technology and methodology are needed. This review describes the state of the art as well as measures which we expect will help overcoming current limitations.
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Affiliation(s)
- Felix J B Bäuerlein
- Max-Planck-Institute of Biochemistry, Department for Molecular Structural Biology, Am Klopferspitz 18, 82152 Planegg, Germany; Georg-August-University, Institute for Neuropathology, Robert-Koch-Strasse 40, 37075 Göttingen, Germany; Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Germany.
| | - Wolfgang Baumeister
- Max-Planck-Institute of Biochemistry, Department for Molecular Structural Biology, Am Klopferspitz 18, 82152 Planegg, Germany.
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219
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Burt A, Gaifas L, Dendooven T, Gutsche I. A flexible framework for multi-particle refinement in cryo-electron tomography. PLoS Biol 2021; 19:e3001319. [PMID: 34437530 PMCID: PMC8389456 DOI: 10.1371/journal.pbio.3001319] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 06/09/2021] [Indexed: 11/19/2022] Open
Abstract
Cryo-electron tomography (cryo-ET) and subtomogram averaging (STA) are increasingly used for macromolecular structure determination in situ. Here, we introduce a set of computational tools and resources designed to enable flexible approaches to STA through increased automation and simplified metadata handling. We create a bidirectional interface between the Dynamo software package and the Warp-Relion-M pipeline, providing a framework for ab initio and geometrical approaches to multiparticle refinement in M. We illustrate the power of working within this framework by applying it to EMPIAR-10164, a publicly available dataset containing immature HIV-1 virus-like particles (VLPs), and a challenging in situ dataset containing chemosensory arrays in bacterial minicells. Additionally, we provide a comprehensive, step-by-step guide to obtaining a 3.4-Å reconstruction from EMPIAR-10164. The guide is hosted on https://teamtomo.org/, a collaborative online platform we establish for sharing knowledge about cryo-ET.
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Affiliation(s)
- Alister Burt
- Institut de Biologie Structurale, Université Grenoble Alpes, CEA, CNRS, IBS, Grenoble, France
| | - Lorenzo Gaifas
- Institut de Biologie Structurale, Université Grenoble Alpes, CEA, CNRS, IBS, Grenoble, France
| | - Tom Dendooven
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Irina Gutsche
- Institut de Biologie Structurale, Université Grenoble Alpes, CEA, CNRS, IBS, Grenoble, France
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220
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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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221
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Masrati G, Landau M, Ben-Tal N, Lupas A, Kosloff M, Kosinski J. Integrative Structural Biology in the Era of Accurate Structure Prediction. J Mol Biol 2021; 433:167127. [PMID: 34224746 DOI: 10.1016/j.jmb.2021.167127] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 06/28/2021] [Accepted: 06/28/2021] [Indexed: 11/16/2022]
Abstract
Characterizing the three-dimensional structure of macromolecules is central to understanding their function. Traditionally, structures of proteins and their complexes have been determined using experimental techniques such as X-ray crystallography, NMR, or cryo-electron microscopy-applied individually or in an integrative manner. Meanwhile, however, computational methods for protein structure prediction have been improving their accuracy, gradually, then suddenly, with the breakthrough advance by AlphaFold2, whose models of monomeric proteins are often as accurate as experimental structures. This breakthrough foreshadows a new era of computational methods that can build accurate models for most monomeric proteins. Here, we envision how such accurate modeling methods can combine with experimental structural biology techniques, enhancing integrative structural biology. We highlight the challenges that arise when considering multiple structural conformations, protein complexes, and polymorphic assemblies. These challenges will motivate further developments, both in modeling programs and in methods to solve experimental structures, towards better and quicker investigation of structure-function relationships.
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Affiliation(s)
- Gal Masrati
- Department of Biochemistry and Molecular Biology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Meytal Landau
- Department of Biology, Technion-Israel Institute of Technology, Haifa 3200003, Israel; European Molecular Biology Laboratory (EMBL), Hamburg 22607, Germany
| | - Nir Ben-Tal
- Department of Biochemistry and Molecular Biology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Andrei Lupas
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany.
| | - Mickey Kosloff
- Department of Human Biology, Faculty of Natural Sciences, University of Haifa, 199 Aba Khoushy Ave., Mt. Carmel, 3498838 Haifa, Israel.
| | - Jan Kosinski
- European Molecular Biology Laboratory (EMBL), Hamburg 22607, Germany; Centre for Structural Systems Biology (CSSB), Hamburg 22607, Germany; Structural and Computational Biology Unit, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany.
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222
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2.85 and 2.99 Å resolution structures of 110 kDa nitrite reductase determined by 200 kV cryogenic electron microscopy. J Struct Biol 2021; 213:107768. [PMID: 34217801 DOI: 10.1016/j.jsb.2021.107768] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 05/22/2021] [Accepted: 06/28/2021] [Indexed: 11/22/2022]
Abstract
Cu-containing nitrite reductases (NiRs) are 110 kDa enzymes that play central roles in denitrification. Although the NiRs have been well studied, with over 100 Protein Data Bank entries, such issues as crystal packing, photoreduction, and lack of high pH cases have impeded structural analysis of their catalytic mechanisms. Here we show the cryogenic electron microscopy (cryo-EM) structures of Achromobacter cycloclastes NiR (AcNiR) at pH 6.2 and 8.1. The optimization of 3D-reconstruction parameters achieved 2.99 and 2.85 Å resolution. Comprehensive comparisons with cryo-EM and 56 AcNiR crystal structures suggested crystallographic artifacts in residues 185-215 and His255' due to packing and photoreduction, respectively. We used a newly developed map comparison method to detect structural change around the type 2 Cu site. While the theoretical estimation of coordinate errors of cryo-EM structures remains difficult, combined analysis using X-ray and cryo-EM structures will allow deeper insight into the local structural changes of proteins.
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223
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Lucas BA, Himes BA, Xue L, Grant T, Mahamid J, Grigorieff N. Locating macromolecular assemblies in cells by 2D template matching with cisTEM. eLife 2021; 10:e68946. [PMID: 34114559 PMCID: PMC8219381 DOI: 10.7554/elife.68946] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 06/09/2021] [Indexed: 12/31/2022] Open
Abstract
For a more complete understanding of molecular mechanisms, it is important to study macromolecules and their assemblies in the broader context of the cell. This context can be visualized at nanometer resolution in three dimensions (3D) using electron cryo-tomography, which requires tilt series to be recorded and computationally aligned, currently limiting throughput. Additionally, the high-resolution signal preserved in the raw tomograms is currently limited by a number of technical difficulties, leading to an increased false-positive detection rate when using 3D template matching to find molecular complexes in tomograms. We have recently described a 2D template matching approach that addresses these issues by including high-resolution signal preserved in single-tilt images. A current limitation of this approach is the high computational cost that limits throughput. We describe here a GPU-accelerated implementation of 2D template matching in the image processing software cisTEM that allows for easy scaling and improves the accessibility of this approach. We apply 2D template matching to identify ribosomes in images of frozen-hydrated Mycoplasma pneumoniae cells with high precision and sensitivity, demonstrating that this is a versatile tool for in situ visual proteomics and in situ structure determination. We benchmark the results with 3D template matching of tomograms acquired on identical sample locations and identify strengths and weaknesses of both techniques, which offer complementary information about target localization and identity.
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Affiliation(s)
- Bronwyn A Lucas
- Howard Hughes Medical Institute, Janelia Research CampusAshburnUnited States
| | - Benjamin A Himes
- Howard Hughes Medical Institute, RNA Therapeutics Institute, The University of Massachusetts Medical SchoolWorcesterUnited States
| | - Liang Xue
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL)HeidelbergGermany
- Collaboration for joint PhD degree between EMBL and Heidelberg University, Faculty of BiosciencesHeidelbergGermany
| | - Timothy Grant
- Howard Hughes Medical Institute, Janelia Research CampusAshburnUnited States
| | - Julia Mahamid
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL)HeidelbergGermany
| | - Nikolaus Grigorieff
- Howard Hughes Medical Institute, RNA Therapeutics Institute, The University of Massachusetts Medical SchoolWorcesterUnited States
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224
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Wang Z, Zhang Q, Mim C. Coming of Age: Cryo-Electron Tomography as a Versatile Tool to Generate High-Resolution Structures at Cellular/Biological Interfaces. Int J Mol Sci 2021; 22:6177. [PMID: 34201105 PMCID: PMC8228724 DOI: 10.3390/ijms22126177] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 06/01/2021] [Accepted: 06/02/2021] [Indexed: 12/29/2022] Open
Abstract
Over the last few years, cryo electron microscopy has become the most important method in structural biology. While 80% of deposited maps are from single particle analysis, electron tomography has grown to become the second most important method. In particular sub-tomogram averaging has matured as a method, delivering structures between 2 and 5 Å from complexes in cells as well as in vitro complexes. While this resolution range is not standard, novel developments point toward a promising future. Here, we provide a guide for the workflow from sample to structure to gain insight into this emerging field.
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Affiliation(s)
| | | | - Carsten Mim
- Department of Biomedical Engineering and Health Systems, Royal Technical Institute (KTH), Hälsovägen 11C, 141 27 Huddinge, Sweden; (Z.W.); (Q.Z.)
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225
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Pyle E, Zanetti G. Current data processing strategies for cryo-electron tomography and subtomogram averaging. Biochem J 2021; 478:1827-1845. [PMID: 34003255 PMCID: PMC8133831 DOI: 10.1042/bcj20200715] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 04/19/2021] [Accepted: 04/26/2021] [Indexed: 12/25/2022]
Abstract
Cryo-electron tomography (cryo-ET) can be used to reconstruct three-dimensional (3D) volumes, or tomograms, from a series of tilted two-dimensional images of biological objects in their near-native states in situ or in vitro. 3D subvolumes, or subtomograms, containing particles of interest can be extracted from tomograms, aligned, and averaged in a process called subtomogram averaging (STA). STA overcomes the low signal to noise ratio within the individual subtomograms to generate structures of the particle(s) of interest. In recent years, cryo-ET with STA has increasingly been capable of reaching subnanometer resolution due to improvements in microscope hardware and data processing strategies. There has also been an increase in the number and quality of software packages available to process cryo-ET data with STA. In this review, we describe and assess the data processing strategies available for cryo-ET data and highlight the recent software developments which have enabled the extraction of high-resolution information from cryo-ET datasets.
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Affiliation(s)
- Euan Pyle
- Institute of Structural and Molecular Biology, Birkbeck College, Malet St., London WC1E 7HX, U.K
| | - Giulia Zanetti
- Institute of Structural and Molecular Biology, Birkbeck College, Malet St., London WC1E 7HX, U.K
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226
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An overview of the recent advances in cryo-electron microscopy for life sciences. Emerg Top Life Sci 2021; 5:151-168. [PMID: 33760078 DOI: 10.1042/etls20200295] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 02/26/2021] [Accepted: 03/09/2021] [Indexed: 01/18/2023]
Abstract
Cryo-electron microscopy (CryoEM) has superseded X-ray crystallography and NMR to emerge as a popular and effective tool for structure determination in recent times. It has become indispensable for the characterization of large macromolecular assemblies, membrane proteins, or samples that are limited, conformationally heterogeneous, and recalcitrant to crystallization. Besides, it is the only tool capable of elucidating high-resolution structures of macromolecules and biological assemblies in situ. A state-of-the-art electron microscope operable at cryo-temperature helps preserve high-resolution details of the biological sample. The structures can be determined, either in isolation via single-particle analysis (SPA) or helical reconstruction, electron diffraction (ED) or within the cellular environment via cryo-electron tomography (cryoET). All the three streams of SPA, ED, and cryoET (along with subtomogram averaging) have undergone significant advancements in recent times. This has resulted in breaking the boundaries with respect to both the size of the macromolecules/assemblies whose structures could be determined along with the visualization of atomic details at resolutions unprecedented for cryoEM. In addition, the collection of larger datasets combined with the ability to sort and process multiple conformational states from the same sample are providing the much-needed link between the protein structures and their functions. In overview, these developments are helping scientists decipher the molecular mechanism of critical cellular processes, solve structures of macromolecules that were challenging targets for structure determination until now, propelling forward the fields of biology and biomedicine. Here, we summarize recent advances and key contributions of the three cryo-electron microscopy streams of SPA, ED, and cryoET.
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227
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Peck A, Yao Q, Brewster AS, Zwart PH, Heumann JM, Sauter NK, Jensen GJ. Challenges in solving structures from radiation-damaged tomograms of protein nanocrystals assessed by simulation. Acta Crystallogr D Struct Biol 2021; 77:572-586. [PMID: 33950014 PMCID: PMC8098477 DOI: 10.1107/s2059798321002369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Accepted: 03/02/2021] [Indexed: 11/11/2022] Open
Abstract
Structure-determination methods are needed to resolve the atomic details that underlie protein function. X-ray crystallography has provided most of our knowledge of protein structure, but is constrained by the need for large, well ordered crystals and the loss of phase information. The rapidly developing methods of serial femtosecond crystallography, micro-electron diffraction and single-particle reconstruction circumvent the first of these limitations by enabling data collection from nanocrystals or purified proteins. However, the first two methods also suffer from the phase problem, while many proteins fall below the molecular-weight threshold required for single-particle reconstruction. Cryo-electron tomography of protein nanocrystals has the potential to overcome these obstacles of mainstream structure-determination methods. Here, a data-processing scheme is presented that combines routines from X-ray crystallography and new algorithms that have been developed to solve structures from tomograms of nanocrystals. This pipeline handles image-processing challenges specific to tomographic sampling of periodic specimens and is validated using simulated crystals. The tolerance of this workflow to the effects of radiation damage is also assessed. The simulations indicate a trade-off between a wider tilt range to facilitate merging data from multiple tomograms and a smaller tilt increment to improve phase accuracy. Since phase errors, but not merging errors, can be overcome with additional data sets, these results recommend distributing the dose over a wide angular range rather than using a finer sampling interval to solve the protein structure.
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Affiliation(s)
- Ariana Peck
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Qing Yao
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Aaron S. Brewster
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Petrus H. Zwart
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Center for Advanced Mathematics in Energy Research Applications, Lawrence Berkeley National Laboratory, Berkeley CA 94720, USA
| | - John M. Heumann
- Department of Molecular, Cellular and Developmental Biology, University of Colorado Boulder, Boulder, CO 80309, USA
| | - Nicholas K. Sauter
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Grant J. Jensen
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
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228
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Wang Z, Grange M, Wagner T, Kho AL, Gautel M, Raunser S. The molecular basis for sarcomere organization in vertebrate skeletal muscle. Cell 2021; 184:2135-2150.e13. [PMID: 33765442 PMCID: PMC8054911 DOI: 10.1016/j.cell.2021.02.047] [Citation(s) in RCA: 82] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 01/27/2021] [Accepted: 02/22/2021] [Indexed: 12/20/2022]
Abstract
Sarcomeres are force-generating and load-bearing devices of muscles. A precise molecular picture of how sarcomeres are built underpins understanding their role in health and disease. Here, we determine the molecular architecture of native vertebrate skeletal sarcomeres by electron cryo-tomography. Our reconstruction reveals molecular details of the three-dimensional organization and interaction of actin and myosin in the A-band, I-band, and Z-disc and demonstrates that α-actinin cross-links antiparallel actin filaments by forming doublets with 6-nm spacing. Structures of myosin, tropomyosin, and actin at ~10 Å further reveal two conformations of the "double-head" myosin, where the flexible orientation of the lever arm and light chains enable myosin not only to interact with the same actin filament, but also to split between two actin filaments. Our results provide unexpected insights into the fundamental organization of vertebrate skeletal muscle and serve as a strong foundation for future investigations of muscle diseases.
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Affiliation(s)
- Zhexin Wang
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany
| | - Michael Grange
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany
| | - Thorsten Wagner
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany
| | - Ay Lin Kho
- The Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences, Kings College London BHF Excellence Centre, New Hunt's House, Guy's Campus, London SE1 1UL, UK
| | - Mathias Gautel
- The Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences, Kings College London BHF Excellence Centre, New Hunt's House, Guy's Campus, London SE1 1UL, UK
| | - Stefan Raunser
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany.
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229
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Julia Mahamid. Nat Methods 2021; 18:117. [PMID: 33542512 DOI: 10.1038/s41592-021-01063-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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230
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Bouvette J, Liu HF, Du X, Zhou Y, Sikkema AP, da Fonseca Rezende E Mello J, Klemm BP, Huang R, Schaaper RM, Borgnia MJ, Bartesaghi A. Beam image-shift accelerated data acquisition for near-atomic resolution single-particle cryo-electron tomography. Nat Commun 2021; 12:1957. [PMID: 33785757 PMCID: PMC8009872 DOI: 10.1038/s41467-021-22251-8] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 03/08/2021] [Indexed: 11/19/2022] Open
Abstract
Tomographic reconstruction of cryopreserved specimens imaged in an electron microscope followed by extraction and averaging of sub-volumes has been successfully used to derive atomic models of macromolecules in their biological environment. Eliminating biochemical isolation steps required by other techniques, this method opens up the cell to in-situ structural studies. However, the need to compensate for errors in targeting introduced during mechanical navigation of the specimen significantly slows down tomographic data collection thus limiting its practical value. Here, we introduce protocols for tilt-series acquisition and processing that accelerate data collection speed by up to an order of magnitude and improve map resolution compared to existing approaches. We achieve this by using beam-image shift to multiply the number of areas imaged at each stage position, by integrating geometrical constraints during imaging to achieve high precision targeting, and by performing per-tilt astigmatic CTF estimation and data-driven exposure weighting to improve final map resolution. We validated our beam image-shift electron cryo-tomography (BISECT) approach by determining the structure of a low molecular weight target (~300 kDa) at 3.6 Å resolution where density for individual side chains is clearly resolved. Tomographic reconstructions of cryopreserved specimens enable in-situ structural studies. Here, the authors present the beam image-shift electron cryo-tomography (BISECT) approach that accelerates data collection speed and improves the map resolution compared to earlier approaches and present the in vitro structure of a 300 kDa protein complex that was solved at 3.6 Å resolution as a test case.
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Affiliation(s)
- Jonathan Bouvette
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, USA
| | - Hsuan-Fu Liu
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, USA
| | - Xiaochen Du
- Department of Computer Science, Duke University, Durham, NC, USA.,Department of Chemistry, Duke University, Durham, NC, USA
| | - Ye Zhou
- Department of Computer Science, Duke University, Durham, NC, USA
| | - Andrew P Sikkema
- Epigenetics & Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, USA
| | - Juliana da Fonseca Rezende E Mello
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, USA
| | - Bradley P Klemm
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, USA
| | - Rick Huang
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, MD, USA
| | - Roel M Schaaper
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, USA
| | - Mario J Borgnia
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, USA.
| | - Alberto Bartesaghi
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, USA. .,Department of Computer Science, Duke University, Durham, NC, USA. .,Department of Electrical and Computer Engineering, Duke University, Durham, NC, USA.
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Turbant F, Partouche D, El Hamoui O, Trépout S, Legoubey T, Wien F, Arluison V. Apomorphine Targets the Pleiotropic Bacterial Regulator Hfq. Antibiotics (Basel) 2021; 10:antibiotics10030257. [PMID: 33806663 PMCID: PMC8000489 DOI: 10.3390/antibiotics10030257] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 02/24/2021] [Accepted: 02/27/2021] [Indexed: 12/15/2022] Open
Abstract
Hfq is a bacterial regulator with key roles in gene expression. The protein notably regulates translation efficiency and RNA decay in Gram-negative bacteria, thanks to its binding to small regulatory noncoding RNAs. This property is of primary importance for bacterial adaptation and survival in hosts. Small RNAs and Hfq are, for instance, involved in the response to antibiotics. Previous work has shown that the E. coli Hfq C-terminal region (Hfq-CTR) self-assembles into an amyloid structure. It was also demonstrated that the green tea compound EpiGallo Catechin Gallate (EGCG) binds to Hfq-CTR amyloid fibrils and remodels them into nonamyloid structures. Thus, compounds that target the amyloid region of Hfq may be used as antibacterial agents. Here, we show that another compound that inhibits amyloid formation, apomorphine, may also serve as a new antibacterial. Our results provide an alternative in order to repurpose apomorphine, commonly used in the treatment of Parkinson’s disease, as an antibiotic to block bacterial adaptation to treat infections.
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Affiliation(s)
- Florian Turbant
- Laboratoire Léon Brillouin LLB, CEA, CNRS UMR12, Université Paris Saclay, CEA Saclay, 91191 Gif-sur-Yvette, France; (F.T.); (D.P.); (T.L.)
| | - David Partouche
- Laboratoire Léon Brillouin LLB, CEA, CNRS UMR12, Université Paris Saclay, CEA Saclay, 91191 Gif-sur-Yvette, France; (F.T.); (D.P.); (T.L.)
- Synchrotron SOLEIL, L’Orme des Merisiers, Saint Aubin BP48, 91192 Gif-sur-Yvette, France;
| | - Omar El Hamoui
- Synchrotron SOLEIL, L’Orme des Merisiers, Saint Aubin BP48, 91192 Gif-sur-Yvette, France;
| | - Sylvain Trépout
- Institut Curie, Inserm US43, and CNRS UMS2016, 91405 Orsay CEDEX, France;
| | - Théa Legoubey
- Laboratoire Léon Brillouin LLB, CEA, CNRS UMR12, Université Paris Saclay, CEA Saclay, 91191 Gif-sur-Yvette, France; (F.T.); (D.P.); (T.L.)
| | - Frank Wien
- Synchrotron SOLEIL, L’Orme des Merisiers, Saint Aubin BP48, 91192 Gif-sur-Yvette, France;
- Correspondence: (F.W.); or (V.A.); Tel.: +33-(0)169359665 (F.W.); +33-(0)169083282 (V.A.)
| | - Véronique Arluison
- Laboratoire Léon Brillouin LLB, CEA, CNRS UMR12, Université Paris Saclay, CEA Saclay, 91191 Gif-sur-Yvette, France; (F.T.); (D.P.); (T.L.)
- UFR Sciences du Vivant, Université de Paris, 75006 Paris CEDEX, France
- Correspondence: (F.W.); or (V.A.); Tel.: +33-(0)169359665 (F.W.); +33-(0)169083282 (V.A.)
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The In Situ Structure of Parkinson's Disease-Linked LRRK2. Cell 2020; 182:1508-1518.e16. [PMID: 32783917 DOI: 10.1016/j.cell.2020.08.004] [Citation(s) in RCA: 119] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 05/28/2020] [Accepted: 07/31/2020] [Indexed: 12/31/2022]
Abstract
Mutations in leucine-rich repeat kinase 2 (LRRK2) are the most frequent cause of familial Parkinson's disease. LRRK2 is a multi-domain protein containing a kinase and GTPase. Using correlative light and electron microscopy, in situ cryo-electron tomography, and subtomogram analysis, we reveal a 14-Å structure of LRRK2 bearing a pathogenic mutation that oligomerizes as a right-handed double helix around microtubules, which are left-handed. Using integrative modeling, we determine the architecture of LRRK2, showing that the GTPase and kinase are in close proximity, with the GTPase closer to the microtubule surface, whereas the kinase is exposed to the cytoplasm. We identify two oligomerization interfaces mediated by non-catalytic domains. Mutation of one of these abolishes LRRK2 microtubule-association. Our work demonstrates the power of cryo-electron tomography to generate models of previously unsolved structures in their cellular environment.
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