1
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Zhao Q, Hong X, Wang Y, Zhang S, Ding Z, Meng X, Song Q, Hong Q, Jiang W, Shi X, Cai T, Cong Y. An immobilized antibody-based affinity grid strategy for on-grid purification of target proteins enables high-resolution cryo-EM. Commun Biol 2024; 7:715. [PMID: 38858498 PMCID: PMC11164986 DOI: 10.1038/s42003-024-06406-z] [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: 01/17/2024] [Accepted: 05/31/2024] [Indexed: 06/12/2024] Open
Abstract
In cryo-electron microscopy (cryo-EM), sample preparation poses a critical bottleneck, particularly for rare or fragile macromolecular assemblies and those suffering from denaturation and particle orientation distribution issues related to air-water interface. In this study, we develop and characterize an immobilized antibody-based affinity grid (IAAG) strategy based on the high-affinity PA tag/NZ-1 antibody epitope tag system. We employ Pyr-NHS as a linker to immobilize NZ-1 Fab on the graphene oxide or carbon-covered grid surface. Our results demonstrate that the IAAG grid effectively enriches PA-tagged target proteins and overcomes preferred orientation issues. Furthermore, we demonstrate the utility of our IAAG strategy for on-grid purification of low-abundance target complexes from cell lysates, enabling atomic resolution cryo-EM. This approach greatly streamlines the purification process, reduces the need for large quantities of biological samples, and addresses common challenges encountered in cryo-EM sample preparation. Collectively, our IAAG strategy provides an efficient and robust means for combined sample purification and vitrification, feasible for high-resolution cryo-EM. This approach holds potential for broader applicability in both cryo-EM and cryo-electron tomography (cryo-ET).
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Affiliation(s)
- Qiaoyu Zhao
- Key Laboratory of RNA Innovation, Science and Engineering, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 200031, Shanghai, China
| | - Xiaoyu Hong
- Key Laboratory of RNA Innovation, Science and Engineering, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 200031, Shanghai, China
| | - Yanxing Wang
- Key Laboratory of RNA Innovation, Science and Engineering, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 200031, Shanghai, China
| | - Shaoning Zhang
- State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 200050, Shanghai, China
| | - Zhanyu Ding
- Key Laboratory of RNA Innovation, Science and Engineering, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 200031, Shanghai, China
| | - Xueming Meng
- Key Laboratory of RNA Innovation, Science and Engineering, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 200031, Shanghai, China
| | - Qianqian Song
- Key Laboratory of RNA Innovation, Science and Engineering, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 200031, Shanghai, China
| | - Qin Hong
- Key Laboratory of RNA Innovation, Science and Engineering, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 200031, Shanghai, China
| | - Wanying Jiang
- Key Laboratory of Systems Health Science of Zhejiang Province, School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, China
| | - Xiangyi Shi
- Shanghai Nanoport, Thermo Fisher Scientific, Shanghai, China
| | - Tianxun Cai
- State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 200050, Shanghai, China
| | - Yao Cong
- Key Laboratory of RNA Innovation, Science and Engineering, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 200031, Shanghai, China.
- Key Laboratory of Systems Health Science of Zhejiang Province, School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, China.
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2
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Ramlaul K, Feng Z, Canavan C, de Martín Garrido N, Carreño D, Crone M, Jensen KE, Li B, Barnett H, Riglar DT, Freemont PS, Miller D, Aylett CHS. A 3D-printed flow-cell for on-grid purification of electron microscopy samples directly from lysate. J Struct Biol 2023; 215:107999. [PMID: 37451560 DOI: 10.1016/j.jsb.2023.107999] [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: 05/30/2023] [Revised: 07/07/2023] [Accepted: 07/10/2023] [Indexed: 07/18/2023]
Abstract
While recent advances in cryo-EM, coupled with single particle analysis, have the potential to allow structure determination in a near-native state from vanishingly few individual particles, this vision has yet to be realised in practise. Requirements for particle numbers that currently far exceed the theoretical lower limits, challenges with the practicalities of achieving high concentrations for difficult-to-produce samples, and inadequate sample-dependent imaging conditions, all result in significant bottlenecks preventing routine structure determination using cryo-EM. Therefore, considerable efforts are being made to circumvent these bottlenecks by developing affinity purification of samples on-grid; at once obviating the need to produce large amounts of protein, as well as more directly controlling the variable, and sample-dependent, process of grid preparation. In this proof-of-concept study, we demonstrate a further practical step towards this paradigm, developing a 3D-printable flow-cell device to allow on-grid affinity purification from raw inputs such as whole cell lysates, using graphene oxide-based affinity grids. Our flow-cell device can be interfaced directly with routinely-used laboratory equipment such as liquid chromatographs, or peristaltic pumps, fitted with standard chromatographic (1/16") connectors, and can be used to allow binding of samples to affinity grids in a controlled environment prior to the extensive washing required to remove impurities. Furthermore, by designing a device which can be 3D printed and coupled to routinely used laboratory equipment, we hope to increase the accessibility of the techniques presented herein to researchers working towards single-particle macromolecular structures.
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Affiliation(s)
- Kailash Ramlaul
- Section for Structural and Synthetic Biology, Department of Infectious Disease, Imperial College London, London, United Kingdom
| | - Ziyi Feng
- Section for Structural and Synthetic Biology, Department of Infectious Disease, Imperial College London, London, United Kingdom
| | - Caoimhe Canavan
- Section for Structural and Synthetic Biology, Department of Infectious Disease, Imperial College London, London, United Kingdom
| | - Natàlia de Martín Garrido
- Section for Structural and Synthetic Biology, Department of Infectious Disease, Imperial College London, London, United Kingdom
| | - David Carreño
- Section for Structural and Synthetic Biology, Department of Infectious Disease, Imperial College London, London, United Kingdom
| | - Michael Crone
- Section for Structural and Synthetic Biology, Department of Infectious Disease, Imperial College London, London, United Kingdom
| | - Kirsten E Jensen
- Section for Structural and Synthetic Biology, Department of Infectious Disease, Imperial College London, London, United Kingdom
| | - Bing Li
- Hamlyn Centre, Department of Brain Sciences, Imperial College London, London, United Kingdom
| | - Harry Barnett
- Imperial College Advanced Hackspace, Imperial College London, London, United Kingdom
| | - David T Riglar
- Section for Structural and Synthetic Biology, Department of Infectious Disease, Imperial College London, London, United Kingdom; The Francis Crick Institute, London, United Kingdom
| | - Paul S Freemont
- Section for Structural and Synthetic Biology, Department of Infectious Disease, Imperial College London, London, United Kingdom
| | - David Miller
- Imperial College Advanced Hackspace, Imperial College London, London, United Kingdom.
| | - Christopher H S Aylett
- Section for Structural and Synthetic Biology, Department of Infectious Disease, Imperial College London, London, United Kingdom.
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3
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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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4
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Liu N, Wang HW. Better Cryo-EM Specimen Preparation: How to Deal with the Air-Water Interface? J Mol Biol 2022; 435:167926. [PMID: 36563741 DOI: 10.1016/j.jmb.2022.167926] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 12/08/2022] [Accepted: 12/14/2022] [Indexed: 12/24/2022]
Abstract
Cryogenic electron microscopy (cryo-EM) is now one of the most powerful and widely used methods to determine high-resolution structures of macromolecules. A major bottleneck of cryo-EM is to prepare high-quality vitrified specimen, which still faces many practical challenges. During the conventional vitrification process, macromolecules tend to adsorb at the air-water interface (AWI), which is known unfriendly to biological samples. In this review, we outline the nature of AWI and the problems caused by it, such as unpredictable or uneven particle distribution, protein denaturation, dissociation of complex and preferential orientation. We review and discuss the approaches and underlying mechanisms to deal with AWI: 1) Additives, exemplified by detergents, forming a protective layer at AWI and thus preserving the native folds of target macromolecules. 2) Fast vitrification devices based on the idea to freeze in-solution macromolecules before their touching of AWI. 3) Thin layer of continuous supporting films to adsorb macromolecules, and when functionalized with affinity ligands, to specifically anchor the target particles away from the AWI. Among these supporting films, graphene, together with its derivatives, with negligible background noise and mechanical robustness, has emerged as a new generation of support. These strategies have been proven successful in various cases and enable us a better handling of the problems caused by the AWI in cryo-EM specimen preparation.
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Affiliation(s)
- Nan Liu
- Ministry of Education Key Laboratory of Protein Sciences, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structures, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Hong-Wei Wang
- Ministry of Education Key Laboratory of Protein Sciences, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structures, School of Life Sciences, Tsinghua University, Beijing 100084, China; Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing 100084, China.
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5
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Fan H, Sun F. Developing Graphene Grids for Cryoelectron Microscopy. Front Mol Biosci 2022; 9:937253. [PMID: 35911962 PMCID: PMC9326159 DOI: 10.3389/fmolb.2022.937253] [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: 05/06/2022] [Accepted: 05/31/2022] [Indexed: 11/13/2022] Open
Abstract
Cryogenic electron microscopy (cryo-EM) single particle analysis has become one of the major techniques used to study high-resolution 3D structures of biological macromolecules. Specimens are generally prepared in a thin layer of vitrified ice using a holey carbon grid. However, the sample quality using this type of grid is not always ideal for high-resolution imaging even when the specimens in the test tube behave ideally. Various problems occur during a vitrification procedure, including poor/nonuniform distribution of particles, preferred orientation of particles, specimen denaturation/degradation, high background from thick ice, and beam-induced motion, which have become important bottlenecks in high-resolution structural studies using cryo-EM in many projects. In recent years, grids with support films made of graphene and its derivatives have been developed to efficiently solve these problems. Here, the various advantages of graphene grids over conventional holey carbon film grids, functionalization of graphene support films, production methods of graphene grids, and origins of pristine graphene contamination are reviewed and discussed.
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Affiliation(s)
- Hongcheng Fan
- National Key Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Fei Sun
- National Key Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
- Center for Biological Imaging, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- Bioland Laboratory, Guangzhou, China
- *Correspondence: Fei Sun,
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6
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Diebolder CA, Dillard RS, Renault L. From Tube to Structure: SPA Cryo-EM Workflow Using Apoferritin as an Example. Methods Mol Biol 2021; 2305:229-256. [PMID: 33950393 DOI: 10.1007/978-1-0716-1406-8_12] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
In this chapter, we present an overview of a standard protocol to achieve structure determination at high resolution by Single Particle Analysis cryogenic Electron Microscopy using apoferritin as a standard sample. The purified apoferritin is applied to a glow-discharged support and then flash frozen in liquid ethane. The prepared grids are loaded into the electron microscope and checked for particle spreading and ice thickness. The microscope alignments are performed and the data collection session is setup for an overnight data collection. The collected movies containing two-dimensional images of the apoferritin sample are then processed to obtain a high-resolution three-dimensional reconstruction.
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Affiliation(s)
- Christoph A Diebolder
- The Netherlands Centre for Electron Nanoscopy (NeCEN), Leiden University, Leiden, The Netherlands
| | - Rebecca S Dillard
- The Netherlands Centre for Electron Nanoscopy (NeCEN), Leiden University, Leiden, The Netherlands
| | - Ludovic Renault
- The Netherlands Centre for Electron Nanoscopy (NeCEN), Leiden University, Leiden, The Netherlands.
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7
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Marcink TC, Wang T, des Georges A, Porotto M, Moscona A. Human parainfluenza virus fusion complex glycoproteins imaged in action on authentic viral surfaces. PLoS Pathog 2020; 16:e1008883. [PMID: 32956394 PMCID: PMC7529294 DOI: 10.1371/journal.ppat.1008883] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 10/01/2020] [Accepted: 08/13/2020] [Indexed: 01/21/2023] Open
Abstract
Infection by human parainfluenza viruses (HPIVs) causes widespread lower respiratory diseases, including croup, bronchiolitis, and pneumonia, and there are no vaccines or effective treatments for these viruses. HPIV3 is a member of the Respirovirus species of the Paramyxoviridae family. These viruses are pleomorphic, enveloped viruses with genomes composed of single-stranded negative-sense RNA. During viral entry, the first step of infection, the viral fusion complex, comprised of the receptor-binding glycoprotein hemagglutinin-neuraminidase (HN) and the fusion glycoprotein (F), mediates fusion upon receptor binding. The HPIV3 transmembrane protein HN, like the receptor-binding proteins of other related viruses that enter host cells using membrane fusion, binds to a receptor molecule on the host cell plasma membrane, which triggers the F glycoprotein to undergo major conformational rearrangements, promoting viral entry. Subsequent fusion of the viral and host membranes allows delivery of the viral genetic material into the host cell. The intermediate states in viral entry are transient and thermodynamically unstable, making it impossible to understand these transitions using standard methods, yet understanding these transition states is important for expanding our knowledge of the viral entry process. In this study, we use cryo-electron tomography (cryo-ET) to dissect the stepwise process by which the receptor-binding protein triggers F-mediated fusion, when forming a complex with receptor-bearing membranes. Using an on-grid antibody capture method that facilitates examination of fresh, biologically active strains of virus directly from supernatant fluids and a series of biological tools that permit the capture of intermediate states in the fusion process, we visualize the series of events that occur when a pristine, authentic viral particle interacts with target receptors and proceeds from the viral entry steps of receptor engagement to membrane fusion.
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Affiliation(s)
- Tara C. Marcink
- Department of Pediatrics, Columbia University Vagelos College of Physicians & Surgeons, New York, New York, United States of America
- Center for Host-Pathogen Interaction, Columbia University Vagelos College of Physicians & Surgeons, New York, New York, United States of America
| | - Tong Wang
- Structural Biology Initiative, CUNY Advanced Science Research Center, New York, New York, United States of America
| | - Amedee des Georges
- Structural Biology Initiative, CUNY Advanced Science Research Center, New York, New York, United States of America
- Department of Chemistry and Biochemistry, City College of New York, New York, New York, United States of America
| | - Matteo Porotto
- Department of Pediatrics, Columbia University Vagelos College of Physicians & Surgeons, New York, New York, United States of America
- Center for Host-Pathogen Interaction, Columbia University Vagelos College of Physicians & Surgeons, New York, New York, United States of America
- Department of Experimental Medicine, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Anne Moscona
- Department of Pediatrics, Columbia University Vagelos College of Physicians & Surgeons, New York, New York, United States of America
- Center for Host-Pathogen Interaction, Columbia University Vagelos College of Physicians & Surgeons, New York, New York, United States of America
- Department of Microbiology & Immunology, Columbia University Vagelos College of Physicians & Surgeons, New York, New York, United States of America
- Department of Physiology & Columbia University Vagelos College of Physicians & Surgeons, New York, New York, United States of America
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8
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Sun C, Gonzalez B, Vago FS, Jiang W. High resolution single particle Cryo-EM refinement using JSPR. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2020; 160:37-42. [PMID: 32622834 DOI: 10.1016/j.pbiomolbio.2020.05.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Revised: 05/06/2020] [Accepted: 05/09/2020] [Indexed: 11/30/2022]
Abstract
JSPR is a single particle cryo-EM image processing and 3D reconstruction software developed in the Jiang laboratory at Purdue University. It began as a few refinement scripts for symmetric and asymmetric reconstructions of icosahedral viruses, but has grown into a comprehensive suite of tools for building ab initio reconstructions, high resolution refinements of viruses, protein complexes of arbitrary symmetries including helical tubes/filaments, and image file handling utilities. In this review, we will present examples achieved using JSPR and demonstrate recently implemented features of JSPR such as multi-aberration "alignments" and automatic optimization of masking for the assessment of map resolution using "true" FSC.
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Affiliation(s)
- Chen Sun
- Department of Biological Sciences, Markey Center for Structural Biology, Purdue University, West Lafayette, IN, 47906, USA
| | - Brenda Gonzalez
- Department of Biological Sciences, Markey Center for Structural Biology, Purdue University, West Lafayette, IN, 47906, USA
| | - Frank S Vago
- Department of Biological Sciences, Markey Center for Structural Biology, Purdue University, West Lafayette, IN, 47906, USA
| | - Wen Jiang
- Department of Biological Sciences, Markey Center for Structural Biology, Purdue University, West Lafayette, IN, 47906, USA.
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9
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McCafferty CL, Verbeke EJ, Marcotte EM, Taylor DW. Structural Biology in the Multi-Omics Era. J Chem Inf Model 2020; 60:2424-2429. [PMID: 32129623 PMCID: PMC7254829 DOI: 10.1021/acs.jcim.9b01164] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Indexed: 12/12/2022]
Abstract
Rapid developments in cryogenic electron microscopy have opened new avenues to probe the structures of protein assemblies in their near native states. Recent studies have begun applying single -particle analysis to heterogeneous mixtures, revealing the potential of structural-omics approaches that combine the power of mass spectrometry and electron microscopy. Here we highlight advances and challenges in sample preparation, data processing, and molecular modeling for handling increasingly complex mixtures. Such advances will help structural-omics methods extend to cellular-level models of structural biology.
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Affiliation(s)
- Caitlyn L. McCafferty
- Department
of Molecular Biosciences, University of
Texas at Austin, Austin, Texas 78712, United States
| | - Eric J. Verbeke
- Department
of Molecular Biosciences, University of
Texas at Austin, Austin, Texas 78712, United States
| | - Edward M. Marcotte
- Department
of Molecular Biosciences, University of
Texas at Austin, Austin, Texas 78712, United States
- Institute
for Cellular and Molecular Biology, University
of Texas at Austin, Austin, Texas 78712, United States
- Center
for Systems and Synthetic Biology, University
of Texas at Austin, Austin, Texas 78712, United States
| | - David W. Taylor
- Department
of Molecular Biosciences, University of
Texas at Austin, Austin, Texas 78712, United States
- Institute
for Cellular and Molecular Biology, University
of Texas at Austin, Austin, Texas 78712, United States
- Center
for Systems and Synthetic Biology, University
of Texas at Austin, Austin, Texas 78712, United States
- LIVESTRONG
Cancer Institutes, Dell Medical School, Austin, Texas 78712, United States
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10
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Kalienkova V, Alvadia C, Clerico Mosina V, Paulino C. Single-Particle Cryo-EM of Membrane Proteins in Lipid Nanodiscs. Methods Mol Biol 2020; 2127:245-273. [PMID: 32112327 DOI: 10.1007/978-1-0716-0373-4_17] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Single-particle cryo-electron microscopy has become an indispensable technique in structural biology. In particular when studying membrane proteins, it allows the use of membrane-mimicking tools, which can be crucial for a comprehensive understanding of the structure-function relationship of the protein in its native environment. In this chapter we focus on the application of nanodiscs and use our recent studies on the TMEM16 family as an example.
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Affiliation(s)
- Valeria Kalienkova
- Department of Structural Biology at the Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, The Netherlands
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Carolina Alvadia
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Vanessa Clerico Mosina
- Department of Structural Biology at the Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, The Netherlands
| | - Cristina Paulino
- Department of Structural Biology at the Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, The Netherlands.
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11
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Murphy RE, Samal AB, Vlach J, Mas V, Prevelige PE, Saad JS. Structural and biophysical characterizations of HIV-1 matrix trimer binding to lipid nanodiscs shed light on virus assembly. J Biol Chem 2019; 294:18600-18612. [PMID: 31640987 PMCID: PMC6901326 DOI: 10.1074/jbc.ra119.010997] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 10/16/2019] [Indexed: 12/17/2022] Open
Abstract
During the late phase of the HIV-1 replication cycle, the viral Gag polyproteins are targeted to the plasma membrane for assembly. The Gag-membrane interaction is mediated by binding of Gag's N-terminal myristoylated matrix (MA) domain to phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2). The viral envelope (Env) glycoprotein is then recruited to the assembly sites and incorporated into budding particles. Evidence suggests that Env incorporation is mediated by interactions between Gag's MA domain and the cytoplasmic tail of the gp41 subunit of Env (gp41CT). MA trimerization appears to be an obligatory step for this interaction. Insufficient production of a recombinant MA trimer and unavailability of a biologically relevant membrane system have been barriers to detailed structural and biophysical characterization of the putative MA-gp41CT-membrane interactions. Here, we engineered a stable recombinant HIV-1 MA trimer construct by fusing a foldon domain (FD) of phage T4 fibritin to the MA C terminus. Results from NMR experiments confirmed that the FD attachment does not adversely alter the MA structure. Employing hydrogen-deuterium exchange MS, we identified an MA-MA interface in the MA trimer that is implicated in Gag assembly and Env incorporation. Utilizing lipid nanodiscs as a membrane mimetic, we show that the MA trimer binds to membranes 30-fold tighter than does the MA monomer and that incorporation of PI(4,5)P2 and phosphatidylserine enhances the binding of MA to nanodiscs. These findings advance our understanding of a fundamental mechanism in HIV-1 assembly and provide a template for investigating the interaction of MA with gp41CT.
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Affiliation(s)
- R Elliot Murphy
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - Alexandra B Samal
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - Jiri Vlach
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - Vicente Mas
- Centro Nacional de Microbiología and CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Peter E Prevelige
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - Jamil S Saad
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama 35294.
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12
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Bednar RM, Golbek TW, Kean KM, Brown WJ, Jana S, Baio JE, Karplus PA, Mehl RA. Immobilization of Proteins with Controlled Load and Orientation. ACS APPLIED MATERIALS & INTERFACES 2019; 11:36391-36398. [PMID: 31525993 DOI: 10.1021/acsami.9b12746] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Biomaterials based on immobilized proteins are key elements of many biomedical and industrial technologies. However, applications are limited by an inability to precisely construct materials of high homogeneity and defined content. We present here a general "protein-limited immobilization" strategy by combining the rapid, bioorthogonal, and biocompatible properties of a tetrazine-strained trans-cyclooctene reaction with genetic code expansion to site-specifically place the tetrazine into a protein. For the first time, we use this strategy to immobilize defined amounts of oriented proteins onto beads and flat surfaces in under 5 min at submicromolar concentrations without compromising activity. This approach opens the door to generating and studying diverse protein-based biomaterials that are much more precisely defined and characterized, providing a greater ability to engineer properties across a wide range of applications.
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Affiliation(s)
- Riley M Bednar
- Department of Biochemistry and Biophysics , Oregon State University , 2011 Agricultural & Life Sciences Building , Corvallis , Oregon 97331-7305 , United States
| | - Thaddeus W Golbek
- School of Chemical, Biological and Environmental Engineering , Oregon State University , 116 Johnson Hall, 105 SW 26th Street , Corvallis , Oregon 97331-7305 , United States
| | - Kelsey M Kean
- Department of Biochemistry and Biophysics , Oregon State University , 2011 Agricultural & Life Sciences Building , Corvallis , Oregon 97331-7305 , United States
| | - Wesley J Brown
- Department of Biochemistry and Biophysics , Oregon State University , 2011 Agricultural & Life Sciences Building , Corvallis , Oregon 97331-7305 , United States
| | - Subhashis Jana
- Department of Biochemistry and Biophysics , Oregon State University , 2011 Agricultural & Life Sciences Building , Corvallis , Oregon 97331-7305 , United States
| | - Joe E Baio
- School of Chemical, Biological and Environmental Engineering , Oregon State University , 116 Johnson Hall, 105 SW 26th Street , Corvallis , Oregon 97331-7305 , United States
| | - P Andrew Karplus
- Department of Biochemistry and Biophysics , Oregon State University , 2011 Agricultural & Life Sciences Building , Corvallis , Oregon 97331-7305 , United States
| | - Ryan A Mehl
- Department of Biochemistry and Biophysics , Oregon State University , 2011 Agricultural & Life Sciences Building , Corvallis , Oregon 97331-7305 , United States
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13
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Jiang QX. Structural Variability in the RLR-MAVS Pathway and Sensitive Detection of Viral RNAs. Med Chem 2019; 15:443-458. [PMID: 30569868 DOI: 10.2174/1573406415666181219101613] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Revised: 10/23/2018] [Accepted: 12/12/2018] [Indexed: 12/25/2022]
Abstract
Cells need high-sensitivity detection of non-self molecules in order to fight against pathogens. These cellular sensors are thus of significant importance to medicinal purposes, especially for treating novel emerging pathogens. RIG-I-like receptors (RLRs) are intracellular sensors for viral RNAs (vRNAs). Their active forms activate mitochondrial antiviral signaling protein (MAVS) and trigger downstream immune responses against viral infection. Functional and structural studies of the RLR-MAVS signaling pathway have revealed significant supramolecular variability in the past few years, which revealed different aspects of the functional signaling pathway. Here I will discuss the molecular events of RLR-MAVS pathway from the angle of detecting single copy or a very low copy number of vRNAs in the presence of non-specific competition from cytosolic RNAs, and review key structural variability in the RLR / vRNA complexes, the MAVS helical polymers, and the adapter-mediated interactions between the active RLR / vRNA complex and the inactive MAVS in triggering the initiation of the MAVS filaments. These structural variations may not be exclusive to each other, but instead may reflect the adaptation of the signaling pathways to different conditions or reach different levels of sensitivity in its response to exogenous vRNAs.
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Affiliation(s)
- Qiu-Xing Jiang
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32611, United States
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14
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Rice WJ, Cheng A, Noble AJ, Eng ET, Kim LY, Carragher B, Potter CS. Routine determination of ice thickness for cryo-EM grids. J Struct Biol 2018; 204:38-44. [PMID: 29981485 PMCID: PMC6119488 DOI: 10.1016/j.jsb.2018.06.007] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Revised: 06/11/2018] [Accepted: 06/27/2018] [Indexed: 12/12/2022]
Abstract
Recent advances in instrumentation and automation have made cryo-EM a popular method for producing near-atomic resolution structures of a variety of proteins and complexes. Sample preparation is still a limiting factor in collecting high quality data. Thickness of the vitreous ice in which the particles are embedded is one of the many variables that need to be optimized for collection of the highest quality data. Here we present two methods, using either an energy filter or scattering outside the objective aperture, to measure ice thickness for potentially every image collected. Unlike geometrical or tomographic methods, these can be implemented directly in the single particle collection workflow without interrupting or significantly slowing down data collection. We describe the methods as implemented into the Leginon/Appion data collection workflow, along with some examples from test cases. Routine monitoring of ice thickness should prove helpful for optimizing sample preparation, data collection, and data processing.
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Affiliation(s)
- William J. Rice
- National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, United States
| | - Anchi Cheng
- National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, United States
| | - Alex J. Noble
- National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, United States
| | - Edward T. Eng
- National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, United States
| | - Laura Y. Kim
- National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, United States
| | - Bridget Carragher
- National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, United States
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Clinton S. Potter
- National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, United States
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
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15
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Pal S, Ganesan K, Eswaran S. Chemical Crosslinking-Mass Spectrometry (CXL-MS) for Proteomics, Antibody-Drug Conjugates (ADCs) and Cryo-Electron Microscopy (cryo-EM). IUBMB Life 2018; 70:947-960. [DOI: 10.1002/iub.1916] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2018] [Revised: 06/06/2018] [Accepted: 06/27/2018] [Indexed: 01/02/2023]
Affiliation(s)
- Shreya Pal
- Amity University Haryana; Manesar Haryana India
| | | | - Sambasivan Eswaran
- Regional Centre for Biotechnology (Established by DBT, Govt. of India under the auspices of UNESCO); NCR Biotech Science Cluster; Faridabad Haryana India
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16
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Stass R, Ilca SL, Huiskonen JT. Beyond structures of highly symmetric purified viral capsids by cryo-EM. Curr Opin Struct Biol 2018; 52:25-31. [PMID: 30096461 DOI: 10.1016/j.sbi.2018.07.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 07/24/2018] [Accepted: 07/24/2018] [Indexed: 10/28/2022]
Abstract
Cryogenic transmission electron microscopy (cryo-EM) is widely used to determine high-resolution structures of symmetric virus capsids. The method holds promise for extending studies beyond purified capsids and their symmetric protein shells. The non-symmetric genome component has been addressed in dsRNA cypoviruses and ssRNA bacteriophages Qβ and MS2. The structure of human herpes simplex virus type 1 capsids has been determined within intact virions to resolve capsid-tegument interactions. Electron tomography under cryogenic conditions (cryo-ET), has allowed resolving an early membrane fusion intermediate of Rift Valley fever virus. Antibody-affinity based sample grids allow capturing of virions directly from cell cultures or even clinical samples. These and other emerging methods will support studies to address viral entry, assembly and neutralization processes at increasingly high resolutions and native conditions.
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Affiliation(s)
- Robert Stass
- Division of Structural Biology, Wellcome Centre for Human Genetics, Roosevelt Drive, University of Oxford, OX3 7BN Oxford, UK
| | - Serban L Ilca
- Division of Structural Biology, Wellcome Centre for Human Genetics, Roosevelt Drive, University of Oxford, OX3 7BN Oxford, UK
| | - Juha T Huiskonen
- Division of Structural Biology, Wellcome Centre for Human Genetics, Roosevelt Drive, University of Oxford, OX3 7BN Oxford, UK; Helsinki Institute of Life Science HiLIFE and Molecular and Integrative Biosciences Research Program, Faculty of Biological and Environmental Sciences, Viikinkaari 1, University of Helsinki, 00014 Helsinki, Finland.
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17
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Dillard RS, Hampton CM, Strauss JD, Ke Z, Altomara D, Guerrero-Ferreira RC, Kiss G, Wright ER. Biological Applications at the Cutting Edge of Cryo-Electron Microscopy. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2018; 24:406-419. [PMID: 30175702 PMCID: PMC6265046 DOI: 10.1017/s1431927618012382] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Cryo-electron microscopy (cryo-EM) is a powerful tool for macromolecular to near-atomic resolution structure determination in the biological sciences. The specimen is maintained in a near-native environment within a thin film of vitreous ice and imaged in a transmission electron microscope. The images can then be processed by a number of computational methods to produce three-dimensional information. Recent advances in sample preparation, imaging, and data processing have led to tremendous growth in the field of cryo-EM by providing higher resolution structures and the ability to investigate macromolecules within the context of the cell. Here, we review developments in sample preparation methods and substrates, detectors, phase plates, and cryo-correlative light and electron microscopy that have contributed to this expansion. We also have included specific biological applications.
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Affiliation(s)
- Rebecca S Dillard
- 1Division of Pediatric Infectious Diseases,Emory University School of Medicine,Children's Healthcare of Atlanta,Atlanta,GA 30322,USA
| | - Cheri M Hampton
- 1Division of Pediatric Infectious Diseases,Emory University School of Medicine,Children's Healthcare of Atlanta,Atlanta,GA 30322,USA
| | - Joshua D Strauss
- 1Division of Pediatric Infectious Diseases,Emory University School of Medicine,Children's Healthcare of Atlanta,Atlanta,GA 30322,USA
| | - Zunlong Ke
- 1Division of Pediatric Infectious Diseases,Emory University School of Medicine,Children's Healthcare of Atlanta,Atlanta,GA 30322,USA
| | - Deanna Altomara
- 1Division of Pediatric Infectious Diseases,Emory University School of Medicine,Children's Healthcare of Atlanta,Atlanta,GA 30322,USA
| | - Ricardo C Guerrero-Ferreira
- 1Division of Pediatric Infectious Diseases,Emory University School of Medicine,Children's Healthcare of Atlanta,Atlanta,GA 30322,USA
| | - Gabriella Kiss
- 1Division of Pediatric Infectious Diseases,Emory University School of Medicine,Children's Healthcare of Atlanta,Atlanta,GA 30322,USA
| | - Elizabeth R Wright
- 1Division of Pediatric Infectious Diseases,Emory University School of Medicine,Children's Healthcare of Atlanta,Atlanta,GA 30322,USA
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18
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19
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Drulyte I, Johnson RM, Hesketh EL, Hurdiss DL, Scarff CA, Porav SA, Ranson NA, Muench SP, Thompson RF. Approaches to altering particle distributions in cryo-electron microscopy sample preparation. Acta Crystallogr D Struct Biol 2018; 74:560-571. [PMID: 29872006 PMCID: PMC6096488 DOI: 10.1107/s2059798318006496] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 04/26/2018] [Indexed: 11/23/2022] Open
Abstract
Cryo-electron microscopy (cryo-EM) can now be used to determine high-resolution structural information on a diverse range of biological specimens. Recent advances have been driven primarily by developments in microscopes and detectors, and through advances in image-processing software. However, for many single-particle cryo-EM projects, major bottlenecks currently remain at the sample-preparation stage; obtaining cryo-EM grids of sufficient quality for high-resolution single-particle analysis can require the careful optimization of many variables. Common hurdles to overcome include problems associated with the sample itself (buffer components, labile complexes), sample distribution (obtaining the correct concentration, affinity for the support film), preferred orientation, and poor reproducibility of the grid-making process within and between batches. This review outlines a number of methodologies used within the electron-microscopy community to address these challenges, providing a range of approaches which may aid in obtaining optimal grids for high-resolution data collection.
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Affiliation(s)
- Ieva Drulyte
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre for Structural and Molecular Biology, University of Leeds, Leeds LS2 9JT, England
| | - Rachel M. Johnson
- School of Biomedical Sciences, Faculty of Biological Sciences and Astbury Centre for Structural and Molecular Biology, University of Leeds, Leeds LS2 9JT, England
- School of Chemistry, Faculty of Mathematics and Physical Chemistry and Astbury Centre for Structural and Molecular Biology, University of Leeds, Leeds LS2 9JT, England
| | - Emma L. Hesketh
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre for Structural and Molecular Biology, University of Leeds, Leeds LS2 9JT, England
| | - Daniel L. Hurdiss
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre for Structural and Molecular Biology, University of Leeds, Leeds LS2 9JT, England
| | - Charlotte A. Scarff
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre for Structural and Molecular Biology, University of Leeds, Leeds LS2 9JT, England
| | - Sebastian A. Porav
- National Institute for Research and Development of Isotopic and Molecular Technologies, 67-103 Donat, 400293 Cluj-Napoca, Romania
| | - Neil A. Ranson
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre for Structural and Molecular Biology, University of Leeds, Leeds LS2 9JT, England
| | - Stephen P. Muench
- School of Biomedical Sciences, Faculty of Biological Sciences and Astbury Centre for Structural and Molecular Biology, University of Leeds, Leeds LS2 9JT, England
| | - Rebecca F. Thompson
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre for Structural and Molecular Biology, University of Leeds, Leeds LS2 9JT, England
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20
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Wang H, Han W, Takagi J, Cong Y. Yeast Inner-Subunit PA–NZ-1 Labeling Strategy for Accurate Subunit Identification in a Macromolecular Complex through Cryo-EM Analysis. J Mol Biol 2018; 430:1417-1425. [DOI: 10.1016/j.jmb.2018.03.026] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 03/14/2018] [Accepted: 03/25/2018] [Indexed: 12/25/2022]
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21
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Pushing the resolution limit by correcting the Ewald sphere effect in single-particle Cryo-EM reconstructions. Nat Commun 2018; 9:1552. [PMID: 29674632 PMCID: PMC5908801 DOI: 10.1038/s41467-018-04051-9] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 03/28/2018] [Indexed: 01/05/2023] Open
Abstract
The Ewald sphere effect is generally neglected when using the Central Projection Theorem for cryo electron microscopy single-particle reconstructions. This can reduce the resolution of a reconstruction. Here we estimate the attainable resolution and report a “block-based” reconstruction method for extending the resolution limit. We find the Ewald sphere effect limits the resolution of large objects, especially large viruses. After processing two real datasets of large viruses, we show that our procedure can extend the resolution for both datasets and can accommodate the flexibility associated with large protein complexes. Conventional reconstruction methods used in cryo-EM single particle analysis do not take the depth of field effect into account. Here the authors present a block-based reconstruction method to deal with the depth of field effect and show that this approach can improve the resolution of cryo-EM virus structures.
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22
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Gilmore BL, Varano AC, Dearnaley W, Liang Y, Marcinkowski BC, Dukes MJ, Kelly DF. Preparation of Tunable Microchips to Visualize Native Protein Complexes for Single-Particle Electron Microscopy. Methods Mol Biol 2018; 1764:45-58. [PMID: 29605907 DOI: 10.1007/978-1-4939-7759-8_3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Recent advances in technology have enabled single-particle electron microscopy (EM) to rapidly progress as a preferred tool to study protein assemblies. Newly developed materials and methods present viable alternatives to traditional EM specimen preparation. Improved lipid monolayer purification reagents offer considerable flexibility, while ultrathin silicon nitride films provide superior imaging properties to the structural study of protein complexes. Here, we describe the steps for combining monolayer purification with silicon nitride microchips to create a tunable approach for the EM community.
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Affiliation(s)
| | - A Cameron Varano
- Virginia Tech Carilion Research Institute, Roanoke, VA, USA.,Translational Biology, Medicine, and Health Graduate Program, Virginia Tech, Blacksburg, VA, USA
| | | | - Yanping Liang
- Virginia Tech Carilion Research Institute, Roanoke, VA, USA
| | | | | | - Deborah F Kelly
- Virginia Tech Carilion Research Institute, Roanoke, VA, USA. .,Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA.
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23
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Jiang W, Tang L. Atomic cryo-EM structures of viruses. Curr Opin Struct Biol 2017; 46:122-129. [PMID: 28787658 PMCID: PMC5683926 DOI: 10.1016/j.sbi.2017.07.002] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 07/12/2017] [Accepted: 07/19/2017] [Indexed: 01/30/2023]
Abstract
During the development of single particle cryo-EM in past five decades, icosahedral viruses have led the resolution progress owing to their large mass and high symmetry. Many technical advances in cryo-EM were first established with viruses. Since reaching ∼4Å resolution in 2008, it has become a relatively routine task to solve the atomic structure of isolated viruses. The future of structural virology will be increasingly focused on remaining challenges including solving structures of jumbo viruses, intermediate functional states during assembly, maturation, and infection, and in situ structures. Recent demonstrations of near-atomic resolution structure with electron tomography and sub-tomogram averaging opens a new direction for high resolution studies of pleomorphic viruses and the pleomorphic states of icosahedral viruses that have defied past efforts using the single particle cryo-EM approach.
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Affiliation(s)
- Wen Jiang
- Department of Biological Sciences, Immunology and Infectious Disease, Purdue University, 240 S. Martin Jischke Drive, West Lafayette, IN 47907, USA; Department of Chemistry, Immunology and Infectious Disease, Purdue University, 240 S. Martin Jischke Drive, West Lafayette, IN 47907, USA; Markey Center for Structural Biology, Immunology and Infectious Disease, Purdue University, 240 S. Martin Jischke Drive, West Lafayette, IN 47907, USA; Purdue Institute of Inflammation, Immunology and Infectious Disease, Purdue University, 240 S. Martin Jischke Drive, West Lafayette, IN 47907, USA.
| | - Liang Tang
- Department of Molecular Biosciences, University of Kansas, 1200 Sunnyside Avenue, Lawrence, KS 66045, USA.
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24
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Abstract
Recently, dozens of virus structures have been solved to resolutions between 2.5 and 5.0 Å by means of electron cryomicroscopy. With these structures we are now firmly within the "atomic age" of electron cryomicroscopy, as these studies can reveal atomic details of protein and nucleic acid topology and interactions between specific residues. This improvement in resolution has been the result of direct electron detectors and image processing advances. Although enforcing symmetry facilitates reaching near-atomic resolution with fewer particle images, it unfortunately obscures some biologically interesting components of a virus. New approaches on relaxing symmetry and exploring structure dynamics and heterogeneity of viral assemblies have revealed important insights into genome packaging, virion assembly, cell entry, and other stages of the viral life cycle. In the future, novel methods will be required to reveal yet-unknown structural conformations of viruses, relevant to their biological activities. Ultimately, these results hold the promise of answering many unresolved questions linking structural diversity of viruses to their biological functions.
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Affiliation(s)
- Jason T Kaelber
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas 77030.,National Center for Macromolecular Imaging, Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030
| | - Corey F Hryc
- National Center for Macromolecular Imaging, Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030.,Graduate Program in Structural and Computational Biology and Molecular Biophysics, Baylor College of Medicine, Houston, Texas 77030;
| | - Wah Chiu
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas 77030.,National Center for Macromolecular Imaging, Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030.,Graduate Program in Structural and Computational Biology and Molecular Biophysics, Baylor College of Medicine, Houston, Texas 77030;
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25
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Abstract
The pace at which cryo-EM is being adopted as a mainstream tool in structural biology has continued unabated over the past year. Initial successes in obtaining near-atomic resolution structures with cryo-EM were enabled to a large extent by advances in microscope and detector technology. Here, we review some of the complementary technical improvements that are helping sustain the cryo-EM revolution. We highlight advances in image processing that permit high resolution structure determination even in the presence of structural and conformational heterogeneity. We also review selected examples where biochemical strategies for membrane protein stabilization facilitate cryo-EM structure determination, and discuss emerging approaches for further improving the preparation of reliable plunge-frozen specimens.
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26
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Abstract
We present here a new CryoEM grid boxes storage system designed to simplify sample labeling, tracking and retrieval. The system is based on the crystal pucks widely used by the X-ray crystallographic community for storage and shipping of crystals. This system is suitable for any cryoEM laboratory, but especially for large facilities that will need accurate tracking of large numbers of samples coming from different sources.
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27
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Snijder J, Borst AJ, Dosey A, Walls AC, Burrell A, Reddy VS, Kollman JM, Veesler D. Vitrification after multiple rounds of sample application and blotting improves particle density on cryo-electron microscopy grids. J Struct Biol 2017; 198:38-42. [PMID: 28254381 PMCID: PMC5400742 DOI: 10.1016/j.jsb.2017.02.008] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 02/17/2017] [Accepted: 02/20/2017] [Indexed: 11/22/2022]
Abstract
Single particle cryo-electron microscopy (cryoEM) is becoming widely adopted as a tool for structural characterization of biomolecules at near-atomic resolution. Vitrification of the sample to obtain a dense distribution of particles within a single field of view remains a major bottleneck for the success of such experiments. Here, we describe a simple and cost-effective method to increase the density of frozen-hydrated particles on grids with holey carbon support films. It relies on performing multiple rounds of sample application and blotting prior to plunge freezing in liquid ethane. We show that this approach is generally applicable and significantly increases particle density for a range of samples, such as small protein complexes, viruses and filamentous assemblies. The method is versatile, easy to implement, minimizes sample requirements and can enable characterization of samples that would otherwise resist structural studies using single particle cryoEM.
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Affiliation(s)
- Joost Snijder
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Andrew J Borst
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Annie Dosey
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Alexandra C Walls
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Anika Burrell
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Vijay S Reddy
- Department of Integrative Computational and Structural Biology, The Scripps Research Institute, La Jolla, CA, USA
| | - Justin M Kollman
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - David Veesler
- Department of Biochemistry, University of Washington, Seattle, WA, USA.
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28
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Biyani N, Righetto RD, McLeod R, Caujolle-Bert D, Castano-Diez D, Goldie KN, Stahlberg H. Focus: The interface between data collection and data processing in cryo-EM. J Struct Biol 2017; 198:124-133. [PMID: 28344036 DOI: 10.1016/j.jsb.2017.03.007] [Citation(s) in RCA: 133] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 03/17/2017] [Accepted: 03/20/2017] [Indexed: 12/15/2022]
Abstract
We present a new software package called Focus that interfaces cryo-transmission electron microscopy (cryo-EM) data collection with computer image processing. Focus creates a user-friendly environment to import and manage data recorded by direct electron detectors and perform elemental image processing tasks in a high-throughput manner while new data is being acquired at the microscope. It provides the functionality required to remotely monitor the progress of data collection and data processing, which is essential now that automation in cryo-EM allows a steady flow of images of single particles, two-dimensional crystals, or electron tomography data to be recorded in overnight sessions. The rapid detection of any errors that may occur greatly increases the productivity of recording sessions at the electron microscope.
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Affiliation(s)
- Nikhil Biyani
- Center for Cellular Imaging and NanoAnalytics (C-CINA), Biozentrum, University of Basel, Basel, Switzerland
| | - Ricardo D Righetto
- Center for Cellular Imaging and NanoAnalytics (C-CINA), Biozentrum, University of Basel, Basel, Switzerland
| | - Robert McLeod
- Center for Cellular Imaging and NanoAnalytics (C-CINA), Biozentrum, University of Basel, Basel, Switzerland
| | | | | | - Kenneth N Goldie
- Center for Cellular Imaging and NanoAnalytics (C-CINA), Biozentrum, University of Basel, Basel, Switzerland
| | - Henning Stahlberg
- Center for Cellular Imaging and NanoAnalytics (C-CINA), Biozentrum, University of Basel, Basel, Switzerland.
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