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Hao W, Chesnokov YM, Molchanov VS, Podlesnyi PR, Kuklin AI, Skoi VV, Philippova OE. Cryo-electron tomography study of the evolution of wormlike micelles to saturated networks and perforated vesicles. J Colloid Interface Sci 2024; 672:431-445. [PMID: 38850868 DOI: 10.1016/j.jcis.2024.06.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2024] [Revised: 06/02/2024] [Accepted: 06/02/2024] [Indexed: 06/10/2024]
Abstract
HYPOTHESIS The formation of micellar aggregates and the changes in their morphology are crucial for numerous practical applications of surfactants. However, a proper structural characterization of complicated micellar nanostructures remains a challenge. This paper demonstrates the advances of cryo-electron tomography (cryo-ET) in revealing the structural characteristics that accompany the evolution of surfactant aggregates. EXPERIMENTS By using cryo-ET in combination with cryo-transmission electron microscopy (cryo-TEM), small-angle neutron scattering (SANS), and rheometry, studies were carried out on a model system composed of zwitterionic and nonionic surfactants. In this system, the molecular packing parameter was increased gradually by increasing the molar fraction of nonionic surfactant. FINDINGS A series of structural transformations was observed: linear wormlike micelles (WLMs) → branched WLMs → saturated network of multiconnected WLMs → perforated vesicles (stomatosomes). The transformations occur through an increase in the number of branches at the expense of cylindrical subchains and semispherical endcaps. Exponential distribution of subchains length was confirmed experimentally for multiconnected saturated networks. The stomatosomes were formed when the length of subchains becomes much shorter than the persistence length, causing the three-dimensional (3D) structure to transform into a two-dimensional (2D) membrane. This work identifies the mechanism of the structural changes, which can be further used to design various surfactant self-assemblies.
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Affiliation(s)
- Wuyi Hao
- Physics Department, Moscow State University, 119991 Moscow, Russia
| | - Yuri M Chesnokov
- National Research Center "Kurchatov Institute", 123182, Moscow, Russia
| | | | - Pavel R Podlesnyi
- National Research Center "Kurchatov Institute", 123182, Moscow, Russia
| | | | - Vadim V Skoi
- Joint Institute for Nuclear Research, 141980 Dubna, Russia
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2
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Zhao J, Yu X, Shentu X, Li D. The application and development of electron microscopy for three-dimensional reconstruction in life science: a review. Cell Tissue Res 2024; 396:1-18. [PMID: 38416172 DOI: 10.1007/s00441-024-03878-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 02/13/2024] [Indexed: 02/29/2024]
Abstract
Imaging technologies have played a pivotal role in advancing biological research by enabling visualization of biological structures and processes. While traditional electron microscopy (EM) produces two-dimensional images, emerging techniques now allow high-resolution three-dimensional (3D) characterization of specimens in situ, meeting growing needs in molecular and cellular biology. Combining transmission electron microscopy (TEM) with serial sectioning inaugurated 3D imaging, attracting biologists seeking to explore cell ultrastructure and driving advancement of 3D EM reconstruction. By comprehensively and precisely rendering internal structure and distribution, 3D TEM reconstruction provides unparalleled ultrastructural insights into cells and molecules, holding tremendous value for elucidating structure-function relationships and broadly propelling structural biology. Here, we first introduce the principle of 3D reconstruction of cells and tissues by classical approaches in TEM and then discuss modern technologies utilizing TEM and on new SEM-based as well as cryo-electron microscope (cryo-EM) techniques. 3D reconstruction techniques from serial sections, electron tomography (ET), and the recent single-particle analysis (SPA) are examined; the focused ion beam scanning electron microscopy (FIB-SEM), the serial block-face scanning electron microscopy (SBF-SEM), and automatic tape-collecting lathe ultramicrotome (ATUM-SEM) for 3D reconstruction of large volumes are discussed. Finally, we review the challenges and development prospects of these technologies in life science. It aims to provide an informative reference for biological researchers.
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Affiliation(s)
- Jingjing Zhao
- Zhejiang Provincial Key Laboratory of Biometrology and Inspection and Quarantine, College of Life Science, China , Jiliang University, Hangzhou, 310018, China
| | - Xiaoping Yu
- Zhejiang Provincial Key Laboratory of Biometrology and Inspection and Quarantine, College of Life Science, China , Jiliang University, Hangzhou, 310018, China
| | - Xuping Shentu
- Zhejiang Provincial Key Laboratory of Biometrology and Inspection and Quarantine, College of Life Science, China , Jiliang University, Hangzhou, 310018, China
| | - Danting Li
- Zhejiang Provincial Key Laboratory of Biometrology and Inspection and Quarantine, College of Life Science, China , Jiliang University, Hangzhou, 310018, China.
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3
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Last MGF, Voortman LM, Sharp TH. Imaging intracellular components in situ using super-resolution cryo-correlative light and electron microscopy. Methods Cell Biol 2024; 187:223-248. [PMID: 38705626 DOI: 10.1016/bs.mcb.2024.02.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/07/2024]
Abstract
Super-resolution cryo-correlative light and electron microscopy (SRcryoCLEM) is emerging as a powerful method to enable targeted in situ structural studies of biological samples. By combining the high specificity and localization accuracy of single-molecule localization microscopy (cryoSMLM) with the high resolution of cryo-electron tomography (cryoET), this method enables accurately targeted data acquisition and the observation and identification of biomolecules within their natural cellular context. Despite its potential, the adaptation of SRcryoCLEM has been hindered by the need for specialized equipment and expertise. In this chapter, we outline a workflow for cryoSMLM and cryoET-based SRcryoCLEM, and we demonstrate that, given the right tools, it is possible to incorporate cryoSMLM into an established cryoET workflow. Using Vimentin as an exemplary target of interest, we demonstrate all stages of an SRcryoCLEM experiment: performing cryoSMLM, targeting cryoET acquisition based on single-molecule localization maps, and correlation of cryoSMLM and cryoET datasets using scNodes, a software package dedicated to SRcryoCLEM. By showing how SRcryoCLEM enables the imaging of specific intracellular components in situ, we hope to facilitate adoption of the technique within the field of cryoEM.
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Affiliation(s)
- Mart G F Last
- Department of Cell and Chemical Biology, Leiden University Medical Centre, Leiden, The Netherlands
| | - Lenard M Voortman
- Department of Cell and Chemical Biology, Leiden University Medical Centre, Leiden, The Netherlands
| | - Thomas H Sharp
- Department of Cell and Chemical Biology, Leiden University Medical Centre, Leiden, The Netherlands; School of Biochemistry, University of Bristol, Bristol, United Kingdom.
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4
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Gisdon FJ, Zunker M, Wolf JN, Prüfer K, Ackermann J, Welsch C, Koch I. Graph-theoretical prediction of biological modules in quaternary structures of large protein complexes. Bioinformatics 2024; 40:btae112. [PMID: 38449296 DOI: 10.1093/bioinformatics/btae112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 02/07/2024] [Accepted: 03/05/2024] [Indexed: 03/08/2024] Open
Abstract
MOTIVATION The functional complexity of biochemical processes is strongly related to the interplay of proteins and their assembly into protein complexes. In recent years, the discovery and characterization of protein complexes have substantially progressed through advances in cryo-electron microscopy, proteomics, and computational structure prediction. This development results in a strong need for computational approaches to analyse the data of large protein complexes for structural and functional characterization. Here, we aim to provide a suitable approach, which processes the growing number of large protein complexes, to obtain biologically meaningful information on the hierarchical organization of the structures of protein complexes. RESULTS We modelled the quaternary structure of protein complexes as undirected, labelled graphs called complex graphs. In complex graphs, the vertices represent protein chains and the edges spatial chain-chain contacts. We hypothesized that clusters based on the complex graph correspond to functional biological modules. To compute the clusters, we applied the Leiden clustering algorithm. To evaluate our approach, we chose the human respiratory complex I, which has been extensively investigated and exhibits a known biological module structure experimentally validated. Additionally, we characterized a eukaryotic group II chaperonin TRiC/CCT and the head of the bacteriophage Φ29. The analysis of the protein complexes correlated with experimental findings and indicated known functional, biological modules. Using our approach enables not only to predict functional biological modules in large protein complexes with characteristic features but also to investigate the flexibility of specific regions and coformational changes. The predicted modules can aid in the planning and analysis of experiments. AVAILABILITY AND IMPLEMENTATION Jupyter notebooks to reproduce the examples are available on our public GitHub repository: https://github.com/MolBIFFM/PTGLtools/tree/main/PTGLmodulePrediction.
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Affiliation(s)
- Florian J Gisdon
- Goethe University Frankfurt, Molecular Bioinformatics, Institute of Computer Science, Faculty of Computer Science and Mathematics, 60325 Frankfurt am Main, Germany
| | - Mariella Zunker
- Goethe University Frankfurt, Molecular Bioinformatics, Institute of Computer Science, Faculty of Computer Science and Mathematics, 60325 Frankfurt am Main, Germany
| | - Jan Niclas Wolf
- Goethe University Frankfurt, Molecular Bioinformatics, Institute of Computer Science, Faculty of Computer Science and Mathematics, 60325 Frankfurt am Main, Germany
| | - Kai Prüfer
- Goethe University Frankfurt, Molecular Bioinformatics, Institute of Computer Science, Faculty of Computer Science and Mathematics, 60325 Frankfurt am Main, Germany
| | - Jörg Ackermann
- Goethe University Frankfurt, Molecular Bioinformatics, Institute of Computer Science, Faculty of Computer Science and Mathematics, 60325 Frankfurt am Main, Germany
| | - Christoph Welsch
- Goethe University Frankfurt, University Hospital, Medical Clinic 1, 60590 Frankfurt am Main, Germany
| | - Ina Koch
- Goethe University Frankfurt, Molecular Bioinformatics, Institute of Computer Science, Faculty of Computer Science and Mathematics, 60325 Frankfurt am Main, Germany
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5
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Elghobashi-Meinhardt N. ATP hydrolysis captured in atomic detail. Nat Chem 2024; 16:306-307. [PMID: 38429342 DOI: 10.1038/s41557-024-01466-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/03/2024]
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6
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Sobo JM, Alagna NS, Sun SX, Wilson KL, Reddy KL. Lamins: The backbone of the nucleocytoskeleton interface. Curr Opin Cell Biol 2024; 86:102313. [PMID: 38262116 DOI: 10.1016/j.ceb.2023.102313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 12/14/2023] [Accepted: 12/15/2023] [Indexed: 01/25/2024]
Abstract
The nuclear lamina (NL) is a crucial component of the inner nuclear membrane (INM) and consists of lamin filaments and associated proteins. Lamins are type V intermediate filament proteins essential for maintaining the integrity and mechanical properties of the nucleus. In human cells, 'B-type' lamins (lamin B1 and lamin B2) are ubiquitously expressed, while 'A-type' lamins (lamin A, lamin C, and minor isoforms) are expressed in a tissue- and development-specific manner. Lamins homopolymerize to form filaments that localize primarily near the INM, but A-type lamins also localize to and function in the nucleoplasm. Lamins play central roles in the assembly, structure, positioning, and mechanics of the nucleus, modulating cell signaling and influencing development, differentiation, and other activities. This review highlights recent findings on the structure and regulation of lamin filaments, providing insights into their multifaceted functions, including their role as "mechanosensors", delving into the emerging significance of lamin filaments as vital links between cytoskeletal and nuclear structures, chromatin organization, and the genome.
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Affiliation(s)
- Joan M Sobo
- Department of Biological Chemistry, Center for Epigenetics, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Nicholas S Alagna
- Department of Biological Chemistry, Center for Epigenetics, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Sean X Sun
- Department of Mechanical Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Katherine L Wilson
- Department of Cell Biology, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Karen L Reddy
- Department of Biological Chemistry, Center for Epigenetics, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA; Sidney Kimmel Comprehensive Cancer Center, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA.
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7
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Nesterov SV, Plokhikh KS, Chesnokov YM, Mustafin DA, Goleva TN, Rogov AG, Vasilov RG, Yaguzhinsky LS. Safari with an Electron Gun: Visualization of Protein and Membrane Interactions in Mitochondria in Natural Environment. BIOCHEMISTRY. BIOKHIMIIA 2024; 89:257-268. [PMID: 38622094 DOI: 10.1134/s0006297924020068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2023] [Revised: 02/06/2024] [Accepted: 02/07/2024] [Indexed: 04/17/2024]
Abstract
This paper presents new structural data about mitochondria using correlative light and electron microscopy (CLEM) and cryo-electron tomography. These state-of-the-art structural biology methods allow studying biological objects at nanometer scales under natural conditions. Non-invasiveness of these methods makes them comparable to observing animals in their natural environment on a safari. The paper highlights two areas of research that can only be accomplished using these methods. The study visualized location of the Aβ42 amyloid aggregates in relation to mitochondria to test a hypothesis of development of mitochondrial dysfunction in Alzheimer's disease. The results showed that the Aβ42 aggregates do not interact with mitochondria, although some of them are closely located. Therefore, the study demonstrated that mitochondrial dysfunction is not directly associated with the effects of aggregates on mitochondrial structure. Other processes should be considered as sources of mitochondrial dysfunction. Second unique area presented in this work is high-resolution visualization of the mitochondrial membranes and proteins in them. Analysis of the cryo-ET data reveals toroidal holes in the lamellar structures of cardiac mitochondrial cristae, where ATP synthases are located. The study proposes a new mechanism for sorting and clustering protein complexes in the membrane based on topology. According to this suggestion, position of the OXPHOS system proteins in the membrane is determined by its curvature. High-resolution tomography expands and complements existing ideas about the structural and functional organization of mitochondria. This makes it possible to study the previously inaccessible structural interactions of proteins with each other and with membranes in vivo.
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Affiliation(s)
- Semen V Nesterov
- National Research Center "Kurchatov Institute", Moscow, 123182, Russia.
| | | | - Yuriy M Chesnokov
- National Research Center "Kurchatov Institute", Moscow, 123182, Russia
| | - Denis A Mustafin
- National Research Center "Kurchatov Institute", Moscow, 123182, Russia
| | - Tatyana N Goleva
- National Research Center "Kurchatov Institute", Moscow, 123182, Russia
| | - Anton G Rogov
- National Research Center "Kurchatov Institute", Moscow, 123182, Russia
| | - Raif G Vasilov
- National Research Center "Kurchatov Institute", Moscow, 123182, Russia
| | - Lev S Yaguzhinsky
- Belozersky Research Institute for Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119992, Russia
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8
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Appasamy SD, Berrisford J, Gaborova R, Nair S, Anyango S, Grudinin S, Deshpande M, Armstrong D, Pidruchna I, Ellaway JIJ, Leines GD, Gupta D, Harrus D, Varadi M, Velankar S. Annotating Macromolecular Complexes in the Protein Data Bank: Improving the FAIRness of Structure Data. Sci Data 2023; 10:853. [PMID: 38040737 PMCID: PMC10692154 DOI: 10.1038/s41597-023-02778-9] [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: 05/15/2023] [Accepted: 11/23/2023] [Indexed: 12/03/2023] Open
Abstract
Macromolecular complexes are essential functional units in nearly all cellular processes, and their atomic-level understanding is critical for elucidating and modulating molecular mechanisms. The Protein Data Bank (PDB) serves as the global repository for experimentally determined structures of macromolecules. Structural data in the PDB offer valuable insights into the dynamics, conformation, and functional states of biological assemblies. However, the current annotation practices lack standardised naming conventions for assemblies in the PDB, complicating the identification of instances representing the same assembly. In this study, we introduce a method leveraging resources external to PDB, such as the Complex Portal, UniProt and Gene Ontology, to describe assemblies and contextualise them within their biological settings accurately. Employing the proposed approach, we assigned standard names to over 90% of unique assemblies in the PDB and provided persistent identifiers for each assembly. This standardisation of assembly data enhances the PDB, facilitating a deeper understanding of macromolecular complexes. Furthermore, the data standardisation improves the PDB's FAIR attributes, fostering more effective basic and translational research and scientific education.
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Affiliation(s)
- Sri Devan Appasamy
- Protein Data Bank in Europe, European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SD, UK.
| | - John Berrisford
- Protein Data Bank in Europe, European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SD, UK
| | - Romana Gaborova
- CEITEC - Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Sreenath Nair
- Protein Data Bank in Europe, European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SD, UK
| | - Stephen Anyango
- Protein Data Bank in Europe, European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SD, UK
| | - Sergei Grudinin
- Univ. Grenoble Alpes, CNRS, Grenoble INP, LJK, 38000, Grenoble, France
| | - Mandar Deshpande
- Protein Data Bank in Europe, European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SD, UK
| | - David Armstrong
- Protein Data Bank in Europe, European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SD, UK
| | - Ivanna Pidruchna
- Protein Data Bank in Europe, European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SD, UK
| | - Joseph I J Ellaway
- Protein Data Bank in Europe, European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SD, UK
| | - Grisell Díaz Leines
- Protein Data Bank in Europe, European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SD, UK
| | - Deepti Gupta
- Protein Data Bank in Europe, European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SD, UK
| | - Deborah Harrus
- Protein Data Bank in Europe, European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SD, UK
| | - Mihaly Varadi
- Protein Data Bank in Europe, European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SD, UK
| | - Sameer Velankar
- Protein Data Bank in Europe, European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SD, UK
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Westphall MS, Lee KW, Salome AZ, Coon JJ, Grant T. Mass spectrometers as cryoEM grid preparation instruments. Curr Opin Struct Biol 2023; 83:102699. [PMID: 37703606 PMCID: PMC11019453 DOI: 10.1016/j.sbi.2023.102699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2023] [Revised: 07/18/2023] [Accepted: 08/15/2023] [Indexed: 09/15/2023]
Abstract
Structure determination by single-particle cryoEM has matured into a core structural biology technique. Despite many methodological advancements, most cryoEM grids are still prepared using the plunge-freezing method developed ∼40 years ago. Embedding samples in thin films and exposing them to the air-water interface often leads to sample damage and preferential orientation of the particles. Using native mass spectrometry to create cryoEM samples, potentially avoids these problems and allows the use of mass spectrometry sample isolation techniques during EM grid creation. We review the recent publications that have demonstrated protein complexes can be ionized, flown through the mass spectrometer, gently landed onto EM grids, imaged, and reconstructed in 3D. Although many uncertainties and challenges remain, the combination of cryoEM and MS has great potential.
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Affiliation(s)
- Michael S Westphall
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI 53706, United States
| | - Kenneth W Lee
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI 53706, United States
| | - Austin Z Salome
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, United States
| | - Joshua J Coon
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI 53706, United States; Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, United States; Morgridge Institute for Research, 330 N Orchard Street, Madison, WI 53706, United States.
| | - Timothy Grant
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, United States; Morgridge Institute for Research, 330 N Orchard Street, Madison, WI 53706, United States.
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Lucas BA, Himes BA, Grigorieff N. Baited reconstruction with 2D template matching for high-resolution structure determination in vitro and in vivo without template bias. eLife 2023; 12:RP90486. [PMID: 38010355 PMCID: PMC10681363 DOI: 10.7554/elife.90486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2023] Open
Abstract
Previously we showed that 2D template matching (2DTM) can be used to localize macromolecular complexes in images recorded by cryogenic electron microscopy (cryo-EM) with high precision, even in the presence of noise and cellular background (Lucas et al., 2021; Lucas et al., 2022). Here, we show that once localized, these particles may be averaged together to generate high-resolution 3D reconstructions. However, regions included in the template may suffer from template bias, leading to inflated resolution estimates and making the interpretation of high-resolution features unreliable. We evaluate conditions that minimize template bias while retaining the benefits of high-precision localization, and we show that molecular features not present in the template can be reconstructed at high resolution from targets found by 2DTM, extending prior work at low-resolution. Moreover, we present a quantitative metric for template bias to aid the interpretation of 3D reconstructions calculated with particles localized using high-resolution templates and fine angular sampling.
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Affiliation(s)
- Bronwyn A Lucas
- RNA Therapeutics Institute, University of Massachusetts Chan Medical SchoolWorcesterUnited States
- Department of Molecular and Cell Biology, University of California BerkeleyBerkeleyUnited States
- Center for Computational Biology, University of California BerkeleyBerkeleyUnited States
| | - Benjamin A Himes
- RNA Therapeutics Institute, University of Massachusetts Chan Medical SchoolWorcesterUnited States
- Howard Hughes Medical InstituteChevy ChaseUnited States
| | - Nikolaus Grigorieff
- RNA Therapeutics Institute, University of Massachusetts Chan Medical SchoolWorcesterUnited States
- Howard Hughes Medical InstituteChevy ChaseUnited States
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11
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Krempl C, Lazzaretti D, Sprangers R. A structural biology view on the enzymes involved in eukaryotic mRNA turnover. Biol Chem 2023; 404:1101-1121. [PMID: 37709756 DOI: 10.1515/hsz-2023-0182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Accepted: 08/24/2023] [Indexed: 09/16/2023]
Abstract
The cellular environment contains numerous ribonucleases that are dedicated to process mRNA transcripts that have been targeted for degradation. Here, we review the three dimensional structures of the ribonuclease complexes (Pan2-Pan3, Ccr4-Not, Xrn1, exosome) and the mRNA decapping enzymes (Dcp2, DcpS) that are involved in mRNA turnover. Structures of major parts of these proteins have been experimentally determined. These enzymes and factors do not act in isolation, but are embedded in interaction networks which regulate enzyme activity and ensure that the appropriate substrates are recruited. The structural details of the higher order complexes that form can, in part, be accurately deduced from known structural data of sub-complexes. Interestingly, many of the ribonuclease and decapping enzymes have been observed in structurally different conformations. Together with experimental data, this highlights that structural changes are often important for enzyme function. We conclude that the known structural data of mRNA decay factors provide important functional insights, but that static structural data needs to be complemented with information regarding protein motions to complete the picture of how transcripts are turned over. In addition, we highlight multiple aspects that influence mRNA turnover rates, but that have not been structurally characterized so far.
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Affiliation(s)
- Christina Krempl
- Institute of Biophysics and Physical Biochemistry, Regensburg Center for Biochemistry, University of Regensburg, D-93053 Regensburg, Germany
| | - Daniela Lazzaretti
- Institute of Biophysics and Physical Biochemistry, Regensburg Center for Biochemistry, University of Regensburg, D-93053 Regensburg, Germany
| | - Remco Sprangers
- Institute of Biophysics and Physical Biochemistry, Regensburg Center for Biochemistry, University of Regensburg, D-93053 Regensburg, Germany
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Olenginski LT, Attionu SK, Henninger EN, LeBlanc RM, Longhini AP, Dayie TK. Hepatitis B Virus Epsilon (ε) RNA Element: Dynamic Regulator of Viral Replication and Attractive Therapeutic Target. Viruses 2023; 15:1913. [PMID: 37766319 PMCID: PMC10534774 DOI: 10.3390/v15091913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Revised: 09/01/2023] [Accepted: 09/05/2023] [Indexed: 09/29/2023] Open
Abstract
Hepatitis B virus (HBV) chronically infects millions of people worldwide, which underscores the importance of discovering and designing novel anti-HBV therapeutics to complement current treatment strategies. An underexploited but attractive therapeutic target is ε, a cis-acting regulatory stem-loop RNA situated within the HBV pregenomic RNA (pgRNA). The binding of ε to the viral polymerase protein (P) is pivotal, as it triggers the packaging of pgRNA and P, as well as the reverse transcription of the viral genome. Consequently, small molecules capable of disrupting this interaction hold the potential to inhibit the early stages of HBV replication. The rational design of such ligands necessitates high-resolution structural information for the ε-P complex or its individual components. While these data are currently unavailable for P, our recent structural elucidation of ε through solution nuclear magnetic resonance spectroscopy marks a significant advancement in this area. In this review, we provide a brief overview of HBV replication and some of the therapeutic strategies to combat chronic HBV infection. These descriptions are intended to contextualize our recent experimental efforts to characterize ε and identify ε-targeting ligands, with the ultimate goal of developing novel anti-HBV therapeutics.
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Affiliation(s)
- Lukasz T. Olenginski
- Center for Biomolecular Structure and Organization, Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA (R.M.L.)
- Department of Biochemistry, University of Colorado, Boulder, CO 80309, USA
| | - Solomon K. Attionu
- Center for Biomolecular Structure and Organization, Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA (R.M.L.)
| | - Erica N. Henninger
- Center for Biomolecular Structure and Organization, Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA (R.M.L.)
| | - Regan M. LeBlanc
- Center for Biomolecular Structure and Organization, Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA (R.M.L.)
| | - Andrew P. Longhini
- Center for Biomolecular Structure and Organization, Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA (R.M.L.)
- Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Theodore K. Dayie
- Center for Biomolecular Structure and Organization, Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA (R.M.L.)
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Santos MFA, Pessoa JC. Interaction of Vanadium Complexes with Proteins: Revisiting the Reported Structures in the Protein Data Bank (PDB) since 2015. Molecules 2023; 28:6538. [PMID: 37764313 PMCID: PMC10536487 DOI: 10.3390/molecules28186538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 09/04/2023] [Accepted: 09/05/2023] [Indexed: 09/29/2023] Open
Abstract
The structural determination and characterization of molecules, namely proteins and enzymes, is crucial to gaining a better understanding of their role in different chemical and biological processes. The continuous technical developments in the experimental and computational resources of X-ray diffraction (XRD) and, more recently, cryogenic Electron Microscopy (cryo-EM) led to an enormous growth in the number of structures deposited in the Protein Data Bank (PDB). Bioinorganic chemistry arose as a relevant discipline in biology and therapeutics, with a massive number of studies reporting the effects of metal complexes on biological systems, with vanadium complexes being one of the relevant systems addressed. In this review, we focus on the interactions of vanadium compounds (VCs) with proteins. Several types of binding are established between VCs and proteins/enzymes. Considering that the V-species that bind may differ from those initially added, the mentioned structural techniques are pivotal to clarifying the nature and variety of interactions of VCs with proteins and to proposing the mechanisms involved either in enzymatic inhibition or catalysis. As such, we provide an account of the available structural information of VCs bound to proteins obtained by both XRD and/or cryo-EM, mainly exploring the more recent structures, particularly those containing organic-based vanadium complexes.
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Affiliation(s)
- Marino F. A. Santos
- Associate Laboratory i4HB—Institute for Health and Bioeconomy, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal
- UCIBIO—Applied Molecular Biosciences Unit, Chemistry Department, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal
- Centro de Química Estrutural, Departamento de Engenharia Química, Institute of Molecular Sciences, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal
| | - João Costa Pessoa
- Centro de Química Estrutural, Departamento de Engenharia Química, Institute of Molecular Sciences, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal
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Aganovic A. pH-dependent endocytosis mechanisms for influenza A and SARS-coronavirus. Front Microbiol 2023; 14:1190463. [PMID: 37234537 PMCID: PMC10206014 DOI: 10.3389/fmicb.2023.1190463] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 04/24/2023] [Indexed: 05/28/2023] Open
Abstract
The ongoing SARS-CoV-2 pandemic and the influenza epidemics have revived the interest in understanding how these highly contagious enveloped viruses respond to alterations in the physicochemical properties of their microenvironment. By understanding the mechanisms and conditions by which viruses exploit the pH environment of the host cell during endocytosis, we can gain a better understanding of how they respond to pH-regulated anti-viral therapies but also pH-induced changes in extracellular environments. This review provides a detailed explanation of the pH-dependent viral structural changes preceding and initiating viral disassembly during endocytosis for influenza A (IAV) and SARS coronaviruses. Drawing upon extensive literature from the last few decades and latest research, I analyze and compare the circumstances in which IAV and SARS-coronavirus can undertake endocytotic pathways that are pH-dependent. While there are similarities in the pH-regulated patterns leading to fusion, the mechanisms and pH activation differ. In terms of fusion activity, the measured activation pH values for IAV, across all subtypes and species, vary between approximately 5.0 to 6.0, while SARS-coronavirus necessitates a lower pH of 6.0 or less. The main difference between the pH-dependent endocytic pathways is that the SARS-coronavirus, unlike IAV, require the presence of specific pH-sensitive enzymes (cathepsin L) during endosomal transport. Conversely, the conformational changes in the IAV virus under acidic conditions in endosomes occur due to the specific envelope glycoprotein residues and envelope protein ion channels (viroporins) getting protonated by H+ ions. Despite extensive research over several decades, comprehending the pH-triggered conformational alterations of viruses still poses a significant challenge. The precise mechanisms of protonation mechanisms of certain during endosomal transport for both viruses remain incompletely understood. In absence of evidence, further research is needed.
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Wang X, Lu Y, Lin X, Li J, Zhang Z. An Unsupervised Classification Algorithm for Heterogeneous Cryo-EM Projection Images Based on Autoencoders. Int J Mol Sci 2023; 24:ijms24098380. [PMID: 37176089 PMCID: PMC10179202 DOI: 10.3390/ijms24098380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 04/29/2023] [Accepted: 04/30/2023] [Indexed: 05/15/2023] Open
Abstract
Heterogeneous three-dimensional (3D) reconstruction in single-particle cryo-electron microscopy (cryo-EM) is an important but very challenging technique for recovering the conformational heterogeneity of flexible biological macromolecules such as proteins in different functional states. Heterogeneous projection image classification is a feasible solution to solve the structural heterogeneity problem in single-particle cryo-EM. The majority of heterogeneous projection image classification methods are developed using supervised learning technology or require a large amount of a priori knowledge, such as the orientations or common lines of the projection images, which leads to certain limitations in their practical applications. In this paper, an unsupervised heterogeneous cryo-EM projection image classification algorithm based on autoencoders is proposed, which only needs to know the number of heterogeneous 3D structures in the dataset and does not require any labeling information of the projection images or other a priori knowledge. A simple autoencoder with multi-layer perceptrons trained in iterative mode and a complex autoencoder with residual networks trained in one-pass learning mode are implemented to convert heterogeneous projection images into latent variables. The extracted high-dimensional features are reduced to two dimensions using the uniform manifold approximation and projection dimensionality reduction algorithm, and then clustered using the spectral clustering algorithm. The proposed algorithm is applied to two heterogeneous cryo-EM datasets for heterogeneous 3D reconstruction. Experimental results show that the proposed algorithm can effectively extract category features of heterogeneous projection images and achieve high classification and reconstruction accuracy, indicating that the proposed algorithm is effective for heterogeneous 3D reconstruction in single-particle cryo-EM.
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Affiliation(s)
- Xiangwen Wang
- College of Computer Science and Engineering, Northwest Normal University, Lanzhou 730070, China
| | - Yonggang Lu
- School of Information Science and Engineering, Lanzhou University, Lanzhou 730000, China
| | - Xianghong Lin
- College of Computer Science and Engineering, Northwest Normal University, Lanzhou 730070, China
| | - Jianwei Li
- School of Information Science and Engineering, Lanzhou University, Lanzhou 730000, China
| | - Zequn Zhang
- College of Computer Science and Engineering, Northwest Normal University, Lanzhou 730070, China
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Alexander JAN, Locher KP. Emerging structural insights into C-type glycosyltransferases. Curr Opin Struct Biol 2023; 79:102547. [PMID: 36827761 DOI: 10.1016/j.sbi.2023.102547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2022] [Revised: 12/19/2022] [Accepted: 01/11/2023] [Indexed: 02/24/2023]
Abstract
Glycosyltransferases of the C superfamily (GT-Cs) are enzymes found in all domains of life. They catalyse the stepwise synthesis of oligosaccharides or the transfer of assembled glycans from lipid-linked donor substrates to acceptor proteins. The processes mediated by GT-Cs are required for C-, N- and O-linked glycosylation, all of which are essential post-translational modifications in higher-order eukaryotes. Until recently, GT-Cs were thought to share a conserved structural module of 7 transmembrane helices; however, recently determined GT-C structures revealed novel folds. Here we analyse the growing diversity of GT-C folds and discuss the emergence of two subclasses, termed GT-CA and GT-CB. Further substrate-bound structures are needed to facilitate a molecular understanding of glycan recognition and catalysis in these two subclasses.
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Affiliation(s)
| | - Kaspar P Locher
- Institute of Molecular Biology and Biophysics, ETH Zürich, Zürich, Switzerland.
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