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Manalastas-Cantos K, Adoni KR, Pfeifer M, Märtens B, Grünewald K, Thalassinos K, Topf M. Modeling Flexible Protein Structure With AlphaFold2 and Crosslinking Mass Spectrometry. Mol Cell Proteomics 2024; 23:100724. [PMID: 38266916 PMCID: PMC10884514 DOI: 10.1016/j.mcpro.2024.100724] [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: 09/13/2023] [Revised: 12/23/2023] [Accepted: 12/27/2023] [Indexed: 01/26/2024] Open
Abstract
We propose a pipeline that combines AlphaFold2 (AF2) and crosslinking mass spectrometry (XL-MS) to model the structure of proteins with multiple conformations. The pipeline consists of two main steps: ensemble generation using AF2 and conformer selection using XL-MS data. For conformer selection, we developed two scores-the monolink probability score (MP) and the crosslink probability score (XLP)-both of which are based on residue depth from the protein surface. We benchmarked MP and XLP on a large dataset of decoy protein structures and showed that our scores outperform previously developed scores. We then tested our methodology on three proteins having an open and closed conformation in the Protein Data Bank: Complement component 3 (C3), luciferase, and glutamine-binding periplasmic protein, first generating ensembles using AF2, which were then screened for the open and closed conformations using experimental XL-MS data. In five out of six cases, the most accurate model within the AF2 ensembles-or a conformation within 1 Å of this model-was identified using crosslinks, as assessed through the XLP score. In the remaining case, only the monolinks (assessed through the MP score) successfully identified the open conformation of glutamine-binding periplasmic protein, and these results were further improved by including the "occupancy" of the monolinks. This serves as a compelling proof-of-concept for the effectiveness of monolinks. In contrast, the AF2 assessment score was only able to identify the most accurate conformation in two out of six cases. Our results highlight the complementarity of AF2 with experimental methods like XL-MS, with the MP and XLP scores providing reliable metrics to assess the quality of the predicted models. The MP and XLP scoring functions mentioned above are available at https://gitlab.com/topf-lab/xlms-tools.
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Affiliation(s)
- Karen Manalastas-Cantos
- Center for Data and Computing in Natural Sciences, Universität Hamburg, Hamburg, Germany; Department of Integrative Virology, Leibniz-Institut für Virologie (LIV), Centre for Structural Systems Biology (CSSB), Hamburg, Germany
| | - Kish R Adoni
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London, UK; Institute of Structural and Molecular Biology, Birkbeck College, University of London, London, United Kingdom
| | - Matthias Pfeifer
- Department of Integrative Virology, Leibniz-Institut für Virologie (LIV), Centre for Structural Systems Biology (CSSB), Hamburg, Germany; Universitätsklinikum Hamburg Eppendorf (UKE), Hamburg, Germany
| | - Birgit Märtens
- Department of Integrative Virology, Leibniz-Institut für Virologie (LIV), Centre for Structural Systems Biology (CSSB), Hamburg, Germany; Universitätsklinikum Hamburg Eppendorf (UKE), Hamburg, Germany
| | - Kay Grünewald
- Department of Integrative Virology, Leibniz-Institut für Virologie (LIV), Centre for Structural Systems Biology (CSSB), Hamburg, Germany; Department of Chemistry, Universität Hamburg, Hamburg, Germany
| | - Konstantinos Thalassinos
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London, UK; Institute of Structural and Molecular Biology, Birkbeck College, University of London, London, United Kingdom
| | - Maya Topf
- Department of Integrative Virology, Leibniz-Institut für Virologie (LIV), Centre for Structural Systems Biology (CSSB), Hamburg, Germany; Universitätsklinikum Hamburg Eppendorf (UKE), Hamburg, Germany.
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2
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Huangfu S, Yu X, Sun Z, Jiang B, Chen H. Chemical reagents for the enrichment of modified peptides in MS-based identification. Chem Commun (Camb) 2024; 60:1509-1516. [PMID: 38224214 DOI: 10.1039/d3cc05260e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2024]
Abstract
Chemical reagents with special groups as enrichable handles have empowered the ability to label and enrich modified peptides. Here is an overview of different chemical reagents with affinity tags to isolate labeled peptides and the latest developments of enrichment strategies. Biotin is the most used affinity tag due to its high interaction with avidin. To decrease the unfavorable influence of biotin for its poor efficiency in ionization and fragmentation in downstream MS analysis, cleavable moieties were installed between the reactive groups and biotin to release labeled peptides from the biotin. To minimize the steric hindrance of biotin, a two-step method was developed, for which alkyne- or azide-tagged linkers were firstly used to label peptides and then biotin was installed through click chemistry. Recently, new linkers using a small phosphonic acid as the affinity tag for IMAC or TiO2 enrichment have been developed and successfully used to isolate chemically labeled peptides in XL-MS. A stable P-C instead of P-O bond was introduced to linkers to differentiate labeled and endogenous phosphopeptides. Furthermore, a membrane-permeable phosphonate-containing reagent was reported, which facilitated the study of living systems. Taking a cue from classic chemical reactions, stable metal-complex intermediates, including cobalt and palladium complexes, have been developed as peptide purification systems. Advanced enrichment strategies have also been proposed, such as the two-stage IMAC enrichment method and biotin-based two-step reaction strategy, allowing the reduction of unwanted peptides and improvements for the analysis of specific labeled peptides. Finally, future trends in the area are briefly discussed.
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Affiliation(s)
- Shangwei Huangfu
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, 393 Middle Huaxia Road, Pudong, Shanghai, 201210, China.
- School of Physical Science and Technology, ShanghaiTech University, 393 Middle Huaxia Road, Pudong, Shanghai, 201210, China
| | - Xianqiang Yu
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, 393 Middle Huaxia Road, Pudong, Shanghai, 201210, China.
- School of Physical Science and Technology, ShanghaiTech University, 393 Middle Huaxia Road, Pudong, Shanghai, 201210, China
| | - Ziyu Sun
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, 393 Middle Huaxia Road, Pudong, Shanghai, 201210, China.
- School of Life Science and Technology, ShanghaiTech University, 393 Middle Huaxia Road, Pudong, Shanghai, 201210, China
| | - Biao Jiang
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, 393 Middle Huaxia Road, Pudong, Shanghai, 201210, China.
- School of Physical Science and Technology, ShanghaiTech University, 393 Middle Huaxia Road, Pudong, Shanghai, 201210, China
- School of Life Science and Technology, ShanghaiTech University, 393 Middle Huaxia Road, Pudong, Shanghai, 201210, China
| | - Hongli Chen
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, 393 Middle Huaxia Road, Pudong, Shanghai, 201210, China.
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3
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Hevler JF, Heck AJR. Higher-Order Structural Organization of the Mitochondrial Proteome Charted by In Situ Cross-Linking Mass Spectrometry. Mol Cell Proteomics 2023; 22:100657. [PMID: 37805037 PMCID: PMC10651688 DOI: 10.1016/j.mcpro.2023.100657] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 09/14/2023] [Accepted: 10/04/2023] [Indexed: 10/09/2023] Open
Abstract
Mitochondria are densely packed with proteins, of which most are involved physically or more transiently in protein-protein interactions (PPIs). Mitochondria host among others all enzymes of the Krebs cycle and the oxidative phosphorylation pathway and are foremost associated with cellular bioenergetics. However, mitochondria are also important contributors to apoptotic cell death and contain their own genome indicating that they play additionally an eminent role in processes beyond bioenergetics. Despite intense efforts in identifying and characterizing mitochondrial protein complexes by structural biology and proteomics techniques, many PPIs have remained elusive. Several of these (membrane embedded) PPIs are less stable in vitro hampering their characterization by most contemporary methods in structural biology. Particularly in these cases, cross-linking mass spectrometry (XL-MS) has proven valuable for the in-depth characterization of mitochondrial protein complexes in situ. Here, we highlight experimental strategies for the analysis of proteome-wide PPIs in mitochondria using XL-MS. We showcase the ability of in situ XL-MS as a tool to map suborganelle interactions and topologies and aid in refining structural models of protein complexes. We describe some of the most recent technological advances in XL-MS that may benefit the in situ characterization of PPIs even further, especially when combined with electron microscopy and structural modeling.
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Affiliation(s)
- Johannes F Hevler
- Division of Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, University of Utrecht, Utrecht, The Netherlands; Netherlands Proteomics Center, Utrecht, The Netherlands
| | - Albert J R Heck
- Division of Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, University of Utrecht, Utrecht, The Netherlands; Netherlands Proteomics Center, Utrecht, The Netherlands.
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4
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Gellen G, Klement E, Biwott K, Schlosser G, Kalló G, Csősz É, Medzihradszky KF, Bacso Z. Cross-Linking Mass Spectrometry on P-Glycoprotein. Int J Mol Sci 2023; 24:10627. [PMID: 37445813 DOI: 10.3390/ijms241310627] [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: 05/23/2023] [Revised: 06/21/2023] [Accepted: 06/22/2023] [Indexed: 07/15/2023] Open
Abstract
The ABC transporter P-glycoprotein (Pgp) has been found to be involved in multidrug resistance in tumor cells. Lipids and cholesterol have a pivotal role in Pgp's conformations; however, it is often difficult to investigate it with conventional structural biology techniques. Here, we applied robust approaches coupled with cross-linking mass spectrometry (XL-MS), where the natural lipid environment remains quasi-intact. Two experimental approaches were carried out using different cross-linkers (i) on living cells, followed by membrane preparation and immunoprecipitation enrichment of Pgp, and (ii) on-bead, subsequent to membrane preparation and immunoprecipitation. Pgp-containing complexes were enriched employing extracellular monoclonal anti-Pgp antibodies on magnetic beads, followed by on-bead enzymatic digestion. The LC-MS/MS results revealed mono-links on Pgp's solvent-accessible residues, while intraprotein cross-links confirmed a complex interplay between extracellular, transmembrane, and intracellular segments of the protein, of which several have been reported to be connected to cholesterol. Harnessing the MS results and those of molecular docking, we suggest an epitope for the 15D3 cholesterol-dependent mouse monoclonal antibody. Additionally, enriched neighbors of Pgp prove the strong connection of Pgp to the cytoskeleton and other cholesterol-regulated proteins. These findings suggest that XL-MS may be utilized for protein structure and network analyses in such convoluted systems as membrane proteins.
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Affiliation(s)
- Gabriella Gellen
- MTA-ELTE Lendület Ion Mobility Mass Spectrometry Research Group, Department of Analytical Chemistry, Institute of Chemistry, ELTE Eötvös Loránd University, H-1117 Budapest, Hungary
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Egyetem tér 1., H-4032 Debrecen, Hungary
- Doctoral School of Molecular Cell and Immune Biology, University of Debrecen, Egyetem tér 1., H-4032 Debrecen, Hungary
| | - Eva Klement
- Single Cell Omics Advanced Core Facility, HCEMM, H-6728 Szeged, Hungary
- Laboratory of Proteomics Research, BRC, H-6726 Szeged, Hungary
| | - Kipchumba Biwott
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Egyetem tér 1., H-4032 Debrecen, Hungary
- Doctoral School of Molecular Cell and Immune Biology, University of Debrecen, Egyetem tér 1., H-4032 Debrecen, Hungary
| | - Gitta Schlosser
- MTA-ELTE Lendület Ion Mobility Mass Spectrometry Research Group, Department of Analytical Chemistry, Institute of Chemistry, ELTE Eötvös Loránd University, H-1117 Budapest, Hungary
| | - Gergő Kalló
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, Egyetem tér 1., H-4032 Debrecen, Hungary
- Proteomics Core Facility, Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, Egyetem tér 1., H-4032 Debrecen, Hungary
| | - Éva Csősz
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, Egyetem tér 1., H-4032 Debrecen, Hungary
- Proteomics Core Facility, Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, Egyetem tér 1., H-4032 Debrecen, Hungary
| | | | - Zsolt Bacso
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Egyetem tér 1., H-4032 Debrecen, Hungary
- Doctoral School of Molecular Cell and Immune Biology, University of Debrecen, Egyetem tér 1., H-4032 Debrecen, Hungary
- Faculty of Pharmacology, University of Debrecen, Egyetem tér 1., H-4032 Debrecen, Hungary
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5
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New opportunities in integrative structural modeling. Curr Opin Struct Biol 2022; 77:102488. [PMID: 36279817 DOI: 10.1016/j.sbi.2022.102488] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Revised: 09/13/2022] [Accepted: 09/15/2022] [Indexed: 12/14/2022]
Abstract
Integrative structural modeling enables structure determination of macromolecules and their complexes by integrating data from multiple sources. It has been successfully used to characterize macromolecular structures when a single structural biology technique was insufficient. Recent developments in cellular structural biology, including in-cell cryo-electron tomography and artificial intelligence-based structure prediction, have created new opportunities for integrative structural modeling. Here, we will review these opportunities along with the latest developments in integrative modeling methods and their applications. We also highlight open challenges and directions for further development.
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6
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Sorzano COS, Vilas JL, Ramírez-Aportela E, Krieger J, Del Hoyo D, Herreros D, Fernandez-Giménez E, Marchán D, Macías JR, Sánchez I, Del Caño L, Fonseca-Reyna Y, Conesa P, García-Mena A, Burguet J, García Condado J, Méndez García J, Martínez M, Muñoz-Barrutia A, Marabini R, Vargas J, Carazo JM. Image processing tools for the validation of CryoEM maps. Faraday Discuss 2022; 240:210-227. [PMID: 35861059 DOI: 10.1039/d2fd00059h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The number of maps deposited in public databases (Electron Microscopy Data Bank, EMDB) determined by cryo-electron microscopy has quickly grown in recent years. With this rapid growth, it is critical to guarantee their quality. So far, map validation has primarily focused on the agreement between maps and models. From the image processing perspective, the validation has been mostly restricted to using two half-maps and the measurement of their internal consistency. In this article, we suggest that map validation can be taken much further from the point of view of image processing if 2D classes, particles, angles, coordinates, defoci, and micrographs are also provided. We present a progressive validation scheme that qualifies a result validation status from 0 to 5 and offers three optional qualifiers (A, W, and O) that can be added. The simplest validation state is 0, while the most complete would be 5AWO. This scheme has been implemented in a website https://biocomp.cnb.csic.es/EMValidationService/ to which reconstructed maps and their ESI can be uploaded.
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Affiliation(s)
- C O S Sorzano
- Natl. Center of Biotechnology, CSIC, c/Darwin, 3, 28049, Madrid, Spain.
| | - J L Vilas
- Natl. Center of Biotechnology, CSIC, c/Darwin, 3, 28049, Madrid, Spain.
| | | | - J Krieger
- Natl. Center of Biotechnology, CSIC, c/Darwin, 3, 28049, Madrid, Spain.
| | - D Del Hoyo
- Natl. Center of Biotechnology, CSIC, c/Darwin, 3, 28049, Madrid, Spain.
| | - D Herreros
- Natl. Center of Biotechnology, CSIC, c/Darwin, 3, 28049, Madrid, Spain.
| | | | - D Marchán
- Natl. Center of Biotechnology, CSIC, c/Darwin, 3, 28049, Madrid, Spain.
| | - J R Macías
- Natl. Center of Biotechnology, CSIC, c/Darwin, 3, 28049, Madrid, Spain.
| | - I Sánchez
- Natl. Center of Biotechnology, CSIC, c/Darwin, 3, 28049, Madrid, Spain.
| | - L Del Caño
- Natl. Center of Biotechnology, CSIC, c/Darwin, 3, 28049, Madrid, Spain.
| | - Y Fonseca-Reyna
- Natl. Center of Biotechnology, CSIC, c/Darwin, 3, 28049, Madrid, Spain.
| | - P Conesa
- Natl. Center of Biotechnology, CSIC, c/Darwin, 3, 28049, Madrid, Spain.
| | - A García-Mena
- Natl. Center of Biotechnology, CSIC, c/Darwin, 3, 28049, Madrid, Spain.
| | - J Burguet
- Depto. de Óptica, Univ. Complutense de Madrid, Pl. Ciencias, 1, 28040, Madrid, Spain
| | - J García Condado
- Biocruces Bizkaia Instituto Investigación Sanitaria, Cruces Plaza, 48903, Barakaldo, Bizkaia, Spain
| | | | - M Martínez
- Natl. Center of Biotechnology, CSIC, c/Darwin, 3, 28049, Madrid, Spain.
| | - A Muñoz-Barrutia
- Univ. Carlos III de Madrid, Avda. de la Universidad 30, 28911, Leganés, Madrid, Spain
| | - R Marabini
- Escuela Politécnica Superior, Univ. Autónoma de Madrid, CSIC, C. Francisco Tomás y Valiente, 11, 28049, Madrid, Spain
| | - J Vargas
- Depto. de Óptica, Univ. Complutense de Madrid, Pl. Ciencias, 1, 28040, Madrid, Spain
| | - J M Carazo
- Natl. Center of Biotechnology, CSIC, c/Darwin, 3, 28049, Madrid, Spain.
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7
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Bauzá-Martinez J, Armony G, Pronker MF, Wu W. Characterization of protein complexes in extracellular vesicles by intact extracellular vesicle crosslinking mass spectrometry (iEVXL). J Extracell Vesicles 2022; 11:e12245. [PMID: 35918900 PMCID: PMC9346492 DOI: 10.1002/jev2.12245] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 06/05/2022] [Accepted: 06/25/2022] [Indexed: 11/15/2022] Open
Abstract
Extracellular vesicles (EVs) are blood‐borne messengers that coordinate signalling between different tissues and organs in the body. The specificity of such crosstalk is determined by preferential EV docking to target sites, as mediated through protein‐protein interactions. As such, the need to structurally characterize the EV surface precedes further understanding of docking selectivity and recipient‐cell uptake mechanisms. Here, we describe an intact extracellular vesicle crosslinking mass spectrometry (iEVXL) method that can be applied for structural characterization of protein complexes in EVs. By using a partially membrane‐permeable disuccinimidyl suberate crosslinker, proteins on the EV outer‐surface and inside EVs can be immobilized together with their interacting partners. This not only provides covalent stabilization of protein complexes before extraction from the membrane‐enclosed environment, but also generates a set of crosslinking distance restraints that can be used for structural modelling and comparative screening of changes in EV protein assemblies. Here we demonstrate iEVXL as a powerful approach to reveal high‐resolution information, about protein determinants that govern EV docking and signalling, and as a crucial aid in modelling docking interactions.
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Affiliation(s)
- Julia Bauzá-Martinez
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands.,Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Gad Armony
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands.,Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Matti F Pronker
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands.,Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Wei Wu
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands.,Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore.,Department of Pharmacy, National University of Singapore, Singapore, Singapore
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8
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An Y, Zhao Q, Gao H, Zhao L, Li X, Zhang X, Liang Z, Zhang L, Zhang Y. Selective Removal of Unhydrolyzed Monolinked Peptides from Enriched Crosslinked Peptides To Improve the Coverage of Protein Complex Analysis. Anal Chem 2022; 94:3904-3913. [PMID: 35191685 DOI: 10.1021/acs.analchem.1c04927] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Chemical crosslinking combined with mass spectrometry (CXMS) has allowed the global characterization of protein complexes with high throughput and accuracy. Although enrichable crosslinkers have been introduced to exclude the interference of regular peptides, the crosslinked peptide identification is still severely inhibited by a large amount of monolinked peptides. In this work, we proposed a strategy called MoTE (unhydrolyzed Monolinked peptide Targeting Elimination) to remove the unhydrolyzed monolinked peptides, while enriching crosslinked peptides for regular peptide removal. In this strategy, followed by the crosslinking reaction, an amine biotin reagent was used to block the unreacted reactive groups on the crosslinker, and subsequently, the crosslinked proteins were tagged by a cleavable biotin-azide ligand based on click chemistry for enrichment. The following crosslinked protein digestion, purification by streptavidin beads, and release by chemical cleavage of the biotin-azide ligand were sequentially performed. In this case, the amine biotin-blocked unhydrolyzed monolinked peptides with the unbreakable arm remained on the streptavidin beads, which realized selective removal without any additional steps. By combining in vivo crosslinking with our proposed MoTE strategy for protein complex analysis of the HeLa cell, the number of high reliability (score <E-04) interlinked peptides increased 43% in a single LC-MS run, and the structural and interaction mapping capacity for low-abundance and flexible proteins were greatly enhanced. These results demonstrated that the MoTE strategy has great potential to improve the coverage of CXMS-based protein complex analysis. Notably, it was also the first report focused on removing the highly abundant monolinked peptides.
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Affiliation(s)
- Yuxin An
- CAS Key Laboratory of Separation Science for Analytical Chemistry, National Chromatographic R. & A. Center, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian, Liaoning 116023, China.,University of Chinese Academy of Sciences, Beijing 100039, China
| | - Qun Zhao
- CAS Key Laboratory of Separation Science for Analytical Chemistry, National Chromatographic R. & A. Center, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian, Liaoning 116023, China
| | - Hang Gao
- CAS Key Laboratory of Separation Science for Analytical Chemistry, National Chromatographic R. & A. Center, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian, Liaoning 116023, China.,University of Chinese Academy of Sciences, Beijing 100039, China
| | - Lili Zhao
- CAS Key Laboratory of Separation Science for Analytical Chemistry, National Chromatographic R. & A. Center, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian, Liaoning 116023, China.,University of Chinese Academy of Sciences, Beijing 100039, China
| | - Xiao Li
- CAS Key Laboratory of Separation Science for Analytical Chemistry, National Chromatographic R. & A. Center, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian, Liaoning 116023, China
| | - Xiaodan Zhang
- CAS Key Laboratory of Separation Science for Analytical Chemistry, National Chromatographic R. & A. Center, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian, Liaoning 116023, China
| | - Zhen Liang
- CAS Key Laboratory of Separation Science for Analytical Chemistry, National Chromatographic R. & A. Center, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian, Liaoning 116023, China
| | - Lihua Zhang
- CAS Key Laboratory of Separation Science for Analytical Chemistry, National Chromatographic R. & A. Center, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian, Liaoning 116023, China
| | - Yukui Zhang
- CAS Key Laboratory of Separation Science for Analytical Chemistry, National Chromatographic R. & A. Center, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian, Liaoning 116023, China
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9
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Graziadei A, Rappsilber J. Leveraging crosslinking mass spectrometry in structural and cell biology. Structure 2021; 30:37-54. [PMID: 34895473 DOI: 10.1016/j.str.2021.11.007] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 10/11/2021] [Accepted: 11/17/2021] [Indexed: 12/18/2022]
Abstract
Crosslinking mass spectrometry (crosslinking-MS) is a versatile tool providing structural insights into protein conformation and protein-protein interactions. Its medium-resolution residue-residue distance restraints have been used to validate protein structures proposed by other methods and have helped derive models of protein complexes by integrative structural biology approaches. The use of crosslinking-MS in integrative approaches is underpinned by progress in estimating error rates in crosslinking-MS data and in combining these data with other information. The flexible and high-throughput nature of crosslinking-MS has allowed it to complement the ongoing resolution revolution in electron microscopy by providing system-wide residue-residue distance restraints, especially for flexible regions or systems. Here, we review how crosslinking-MS information has been leveraged in structural model validation and integrative modeling. Crosslinking-MS has also been a key technology for cell biology studies and structural systems biology where, in conjunction with cryoelectron tomography, it can provide structural and mechanistic insights directly in situ.
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Affiliation(s)
- Andrea Graziadei
- Bioanalytics, Institute of Biotechnology, Technische Universität Berlin, 13355 Berlin, Germany
| | - Juri Rappsilber
- Bioanalytics, Institute of Biotechnology, Technische Universität Berlin, 13355 Berlin, Germany; Wellcome Centre for Cell Biology, University of Edinburgh, Max Born Crescent, Edinburgh EH9 3BF, UK.
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10
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Piersimoni L, Kastritis PL, Arlt C, Sinz A. Cross-Linking Mass Spectrometry for Investigating Protein Conformations and Protein-Protein Interactions─A Method for All Seasons. Chem Rev 2021; 122:7500-7531. [PMID: 34797068 DOI: 10.1021/acs.chemrev.1c00786] [Citation(s) in RCA: 92] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Mass spectrometry (MS) has become one of the key technologies of structural biology. In this review, the contributions of chemical cross-linking combined with mass spectrometry (XL-MS) for studying three-dimensional structures of proteins and for investigating protein-protein interactions are outlined. We summarize the most important cross-linking reagents, software tools, and XL-MS workflows and highlight prominent examples for characterizing proteins, their assemblies, and interaction networks in vitro and in vivo. Computational modeling plays a crucial role in deriving 3D-structural information from XL-MS data. Integrating XL-MS with other techniques of structural biology, such as cryo-electron microscopy, has been successful in addressing biological questions that to date could not be answered. XL-MS is therefore expected to play an increasingly important role in structural biology in the future.
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Affiliation(s)
- Lolita Piersimoni
- Department of Pharmaceutical Chemistry & Bioanalytics, Institute of Pharmacy, Kurt-Mothes-Strasse 3, D-06120 Halle (Saale), Germany.,Center for Structural Mass Spectrometry, Kurt-Mothes-Strasse 3, D-06120 Halle (Saale), Germany
| | - Panagiotis L Kastritis
- Interdisciplinary Research Center HALOmem, Charles Tanford Protein Center, Kurt-Mothes-Strasse 3a, D-06120 Halle (Saale), Germany.,Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Strasse 3, D-06120 Halle (Saale), Germany.,Biozentrum, Weinbergweg 22, D-06120 Halle (Saale), Germany
| | - Christian Arlt
- Department of Pharmaceutical Chemistry & Bioanalytics, Institute of Pharmacy, Kurt-Mothes-Strasse 3, D-06120 Halle (Saale), Germany.,Center for Structural Mass Spectrometry, Kurt-Mothes-Strasse 3, D-06120 Halle (Saale), Germany
| | - Andrea Sinz
- Department of Pharmaceutical Chemistry & Bioanalytics, Institute of Pharmacy, Kurt-Mothes-Strasse 3, D-06120 Halle (Saale), Germany.,Center for Structural Mass Spectrometry, Kurt-Mothes-Strasse 3, D-06120 Halle (Saale), Germany
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11
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Britt HM, Cragnolini T, Thalassinos K. Integration of Mass Spectrometry Data for Structural Biology. Chem Rev 2021; 122:7952-7986. [PMID: 34506113 DOI: 10.1021/acs.chemrev.1c00356] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Mass spectrometry (MS) is increasingly being used to probe the structure and dynamics of proteins and the complexes they form with other macromolecules. There are now several specialized MS methods, each with unique sample preparation, data acquisition, and data processing protocols. Collectively, these methods are referred to as structural MS and include cross-linking, hydrogen-deuterium exchange, hydroxyl radical footprinting, native, ion mobility, and top-down MS. Each of these provides a unique type of structural information, ranging from composition and stoichiometry through to residue level proximity and solvent accessibility. Structural MS has proved particularly beneficial in studying protein classes for which analysis by classic structural biology techniques proves challenging such as glycosylated or intrinsically disordered proteins. To capture the structural details for a particular system, especially larger multiprotein complexes, more than one structural MS method with other structural and biophysical techniques is often required. Key to integrating these diverse data are computational strategies and software solutions to facilitate this process. We provide a background to the structural MS methods and briefly summarize other structural methods and how these are combined with MS. We then describe current state of the art approaches for the integration of structural MS data for structural biology. We quantify how often these methods are used together and provide examples where such combinations have been fruitful. To illustrate the power of integrative approaches, we discuss progress in solving the structures of the proteasome and the nuclear pore complex. We also discuss how information from structural MS, particularly pertaining to protein dynamics, is not currently utilized in integrative workflows and how such information can provide a more accurate picture of the systems studied. We conclude by discussing new developments in the MS and computational fields that will further enable in-cell structural studies.
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Affiliation(s)
- Hannah M Britt
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London WC1E 6BT, United Kingdom
| | - Tristan Cragnolini
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London WC1E 6BT, United Kingdom.,Institute of Structural and Molecular Biology, Birkbeck College, University of London, London WC1E 7HX, United Kingdom
| | - Konstantinos Thalassinos
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London WC1E 6BT, United Kingdom.,Institute of Structural and Molecular Biology, Birkbeck College, University of London, London WC1E 7HX, United Kingdom
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12
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Chavez JD, Wippel HH, Tang X, Keller A, Bruce JE. In-Cell Labeling and Mass Spectrometry for Systems-Level Structural Biology. Chem Rev 2021; 122:7647-7689. [PMID: 34232610 PMCID: PMC8966414 DOI: 10.1021/acs.chemrev.1c00223] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Biological systems have evolved to utilize proteins to accomplish nearly all functional roles needed to sustain life. A majority of biological functions occur within the crowded environment inside cells and subcellular compartments where proteins exist in a densely packed complex network of protein-protein interactions. The structural biology field has experienced a renaissance with recent advances in crystallography, NMR, and CryoEM that now produce stunning models of large and complex structures previously unimaginable. Nevertheless, measurements of such structural detail within cellular environments remain elusive. This review will highlight how advances in mass spectrometry, chemical labeling, and informatics capabilities are merging to provide structural insights on proteins, complexes, and networks that exist inside cells. Because of the molecular detection specificity provided by mass spectrometry and proteomics, these approaches provide systems-level information that not only benefits from conventional structural analysis, but also is highly complementary. Although far from comprehensive in their current form, these approaches are currently providing systems structural biology information that can uniquely reveal how conformations and interactions involving many proteins change inside cells with perturbations such as disease, drug treatment, or phenotypic differences. With continued advancements and more widespread adaptation, systems structural biology based on in-cell labeling and mass spectrometry will provide an even greater wealth of structural knowledge.
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Affiliation(s)
- Juan D Chavez
- Department of Genome Sciences, University of Washington, Seattle, Washington 98109, United States
| | - Helisa H Wippel
- Department of Genome Sciences, University of Washington, Seattle, Washington 98109, United States
| | - Xiaoting Tang
- Department of Genome Sciences, University of Washington, Seattle, Washington 98109, United States
| | - Andrew Keller
- Department of Genome Sciences, University of Washington, Seattle, Washington 98109, United States
| | - James E Bruce
- Department of Genome Sciences, University of Washington, Seattle, Washington 98109, United States
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13
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Armony G, Heck AJR, Wu W. Extracellular crosslinking mass spectrometry reveals HLA class I - HLA class II interactions on the cell surface. Mol Immunol 2021; 136:16-25. [PMID: 34052579 DOI: 10.1016/j.molimm.2021.05.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 04/23/2021] [Accepted: 05/19/2021] [Indexed: 01/26/2023]
Abstract
Human Leukocyte Antigen (HLA) complexes are critical cell-surface protein assemblies that facilitate T-cell surveillance of almost all cell types in the body. While T-cell receptor binding to HLA class I and class II complexes is well-described with detailed structural information, the nature of cis HLA interactions within the plasma membrane of the surveyed cells remains to be better characterized, as protein-protein interactions in the membrane environment are technically challenging to profile. Here we performed extracellular chemical crosslinking on intact antigen presenting cells to specifically elucidate protein-protein interactions present in the external plasma membrane. We found that the crosslink dataset was dominated by inter- and intra-protein crosslinks involving HLA molecules, which enabled not only the construction of an HLA-centric plasma membrane protein interaction map, but also revealed multiple modes of HLA class I - HLA class II interactions with further structural modeling based on crosslinker distance restraints. Collectively, our data demonstrate that HLA molecules colocalize and can be densely packed on the plasma membrane.
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Affiliation(s)
- Gad Armony
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands; Netherlands Proteomics Centre, Padualaan 8, 3584 CH, Utrecht, The Netherlands.
| | - Albert J R Heck
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands; Netherlands Proteomics Centre, Padualaan 8, 3584 CH, Utrecht, The Netherlands.
| | - Wei Wu
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands; Netherlands Proteomics Centre, Padualaan 8, 3584 CH, Utrecht, The Netherlands.
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14
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Matzinger M, Mechtler K. Cleavable Cross-Linkers and Mass Spectrometry for the Ultimate Task of Profiling Protein-Protein Interaction Networks in Vivo. J Proteome Res 2021; 20:78-93. [PMID: 33151691 PMCID: PMC7786381 DOI: 10.1021/acs.jproteome.0c00583] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Indexed: 12/11/2022]
Abstract
Cross-linking mass spectrometry (XL-MS) has matured into a potent tool to identify protein-protein interactions or to uncover protein structures in living cells, tissues, or organelles. The unique ability to investigate the interplay of proteins within their native environment delivers valuable complementary information to other advanced structural biology techniques. This Review gives a comprehensive overview of the current possible applications as well as the remaining limitations of the technique, focusing on cross-linking in highly complex biological systems like cells, organelles, or tissues. Thanks to the commercial availability of most reagents and advances in user-friendly data analysis, validation, and visualization tools, studies using XL-MS can, in theory, now also be utilized by nonexpert laboratories.
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Affiliation(s)
- Manuel Matzinger
- Research
Institute of Molecular Pathology (IMP), Campus-Vienna-Biocenter 1, Vienna 1030, Austria
| | - Karl Mechtler
- Research
Institute of Molecular Pathology (IMP), Campus-Vienna-Biocenter 1, Vienna 1030, Austria
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15
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Chavez JD, Keller A, Mohr JP, Bruce JE. Isobaric Quantitative Protein Interaction Reporter Technology for Comparative Interactome Studies. Anal Chem 2020; 92:14094-14102. [PMID: 32969639 DOI: 10.1021/acs.analchem.0c03128] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Chemical cross-linking with mass spectrometry (XL-MS) has emerged as a useful tool for the large-scale study of protein structures and interactions from complex biological samples including intact cells and tissues. Quantitative XL-MS (qXL-MS) provides unique information on protein conformational and interaction changes resulting from perturbations such as drug treatment and disease state. Previous qXL-MS studies relied on the incorporation of stable isotopes into the cross-linker (primarily deuterium) or metabolic labeling with SILAC. Here, we introduce isobaric quantitative protein interaction reporter (iqPIR) technology which utilizes stable isotopes selectively incorporated into the cross-linker design, allowing for isobaric cross-linked peptide pairs originating from different samples to display distinct quantitative isotope signatures in tandem mass spectra. This enables improved quantitation of cross-linked peptide levels from proteome-wide samples because of the reduced complexity of tandem mass spectra relative to MS1 spectra. In addition, because of the isotope incorporation in the reporter and the residual components of the cross-linker that remain on released peptides, each fragmentation spectrum can offer multiple independent opportunities and, therefore, improved confidence for quantitative assessment of the cross-linker pair level. Finally, in addition to providing information on solvent accessibility of lysine sites, dead end iqPIR cross-linked products can provide protein abundance and/or lysine site modification level information all from a single in vivo cross-linking experiment.
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Affiliation(s)
- Juan D Chavez
- Department of Genome Sciences, University of Washington, Seattle 98195, Washington, United States
| | - Andrew Keller
- Department of Genome Sciences, University of Washington, Seattle 98195, Washington, United States
| | - Jared P Mohr
- Department of Genome Sciences, University of Washington, Seattle 98195, Washington, United States
| | - James E Bruce
- Department of Genome Sciences, University of Washington, Seattle 98195, Washington, United States
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16
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Schiffrin B, Radford SE, Brockwell DJ, Calabrese AN. PyXlinkViewer: A flexible tool for visualization of protein chemical crosslinking data within the PyMOL molecular graphics system. Protein Sci 2020; 29:1851-1857. [PMID: 32557917 PMCID: PMC7380677 DOI: 10.1002/pro.3902] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 06/15/2020] [Accepted: 06/16/2020] [Indexed: 01/01/2023]
Abstract
Chemical crosslinking‐mass spectrometry (XL‐MS) is a valuable technique for gaining insights into protein structure and the organization of macromolecular complexes. XL‐MS data yield inter‐residue restraints that can be compared with high‐resolution structural data. Distances greater than the crosslinker spacer‐arm can reveal lowly populated “excited” states of proteins/protein assemblies, or crosslinks can be used as restraints to generate structural models in the absence of structural data. Despite increasing uptake of XL‐MS, there are few tools to enable rapid and facile mapping of XL‐MS data onto high‐resolution structures or structural models. PyXlinkViewer is a user‐friendly plugin for PyMOL v2 that maps intra‐protein, inter‐protein, and dead‐end crosslinks onto protein structures/models and automates the calculation of inter‐residue distances for the detected crosslinks. This enables rapid visualization of XL‐MS data, assessment of whether a set of detected crosslinks is congruent with structural data, and easy production of high‐quality images for publication.
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Affiliation(s)
- Bob Schiffrin
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Sheena E Radford
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - David J Brockwell
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Antonio N Calabrese
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
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