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Chorev DS, Baker LA, Wu D, Beilsten-Edmands V, Rouse SL, Zeev-Ben-Mordehai T, Jiko C, Samsudin F, Gerle C, Khalid S, Stewart AG, Matthews SJ, Grünewald K, Robinson CV. Protein assemblies ejected directly from native membranes yield complexes for mass spectrometry. Science 2018; 362:829-834. [PMID: 30442809 PMCID: PMC6522346 DOI: 10.1126/science.aau0976] [Citation(s) in RCA: 134] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2018] [Accepted: 10/08/2018] [Indexed: 12/25/2022]
Abstract
Membrane proteins reside in lipid bilayers and are typically extracted from this environment for study, which often compromises their integrity. In this work, we ejected intact assemblies from membranes, without chemical disruption, and used mass spectrometry to define their composition. From Escherichia coli outer membranes, we identified a chaperone-porin association and lipid interactions in the β-barrel assembly machinery. We observed efflux pumps bridging inner and outer membranes, and from inner membranes we identified a pentameric pore of TonB, as well as the protein-conducting channel SecYEG in association with F1FO adenosine triphosphate (ATP) synthase. Intact mitochondrial membranes from Bos taurus yielded respiratory complexes and fatty acid-bound dimers of the ADP (adenosine diphosphate)/ATP translocase (ANT-1). These results highlight the importance of native membrane environments for retaining small-molecule binding, subunit interactions, and associated chaperones of the membrane proteome.
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Affiliation(s)
- Dror S Chorev
- Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, UK
| | - Lindsay A Baker
- Division of Structural Biology, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Di Wu
- Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, UK
| | - Victoria Beilsten-Edmands
- Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, UK
| | - Sarah L Rouse
- Department of Life Sciences, Imperial College, London, South Kensington Campus, London SW7 2AZ, UK
| | | | - Chimari Jiko
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, Kumatori, Japan
| | - Firdaus Samsudin
- School of Chemistry, University of Southampton, University Road, Southampton SO17 1BJ, UK
| | - Christoph Gerle
- Institute for Protein Research, Osaka University, Suita, Osaka, Japan
- Core Research for Evolutional Science and Technology, Japan and Science and Technology Agency, Kawaguchi, Japan
| | - Syma Khalid
- School of Chemistry, University of Southampton, University Road, Southampton SO17 1BJ, UK
| | - Alastair G Stewart
- Molecular, Structural and Computational Biology Division, Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia
- Faculty of Medicine, The University of New South Wales, Sydney, NSW, Australia
| | - Stephen J Matthews
- Department of Life Sciences, Imperial College, London, South Kensington Campus, London SW7 2AZ, UK
| | - Kay Grünewald
- Division of Structural Biology, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
- Centre of Structural Systems Biology (CSSB), Notkestr. 85, D-22607, Heinrich-Pette Institute/University of Hamburg, Hamburg, Germany
| | - Carol V Robinson
- Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, UK.
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Schmidt C, Beilsten-Edmands V, Mohammed S, Robinson CV. Acetylation and phosphorylation control both local and global stability of the chloroplast F 1 ATP synthase. Sci Rep 2017; 7:44068. [PMID: 28276484 PMCID: PMC5343439 DOI: 10.1038/srep44068] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 02/03/2017] [Indexed: 12/14/2022] Open
Abstract
ATP synthases (ATPases) are enzymes that produce ATP and control the pH in the cell or cellular compartments. While highly conserved over different species, ATPases are structurally well-characterised but the existence and functional significance of many post-translational modifications (PTMs) is not well understood. We combined a range of mass spectrometric techniques to unravel the location and extent of PTMs in the chloroplast ATP synthase (cATPase) purified from spinach leaves. We identified multiple phosphorylation and acetylation sites and found that both modifications stabilise binding of ε and δ subunits. Comparing cross-linking of naturally modified cATPase with the in vitro deacetylated enzyme revealed a major conformational change in the ε subunit in accord with extended and folded forms of the subunit. Locating modified residues within the catalytic head we found that phosphorylated and acetylated residues are primarily on α/β and β/α interfaces respectively. By aligning along different interfaces the higher abundance acetylated residues are proximal to the regulatory sites while the lower abundance phosphorylation sites are more densely populated at the catalytic sites. We propose that modifications in the catalytic head, together with the conformational change in subunit ε, work in synergy to fine-tune the enzyme during adverse conditions.
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Affiliation(s)
- Carla Schmidt
- Department of Chemistry, University of Oxford, Oxford, United Kingdom
| | | | - Shabaz Mohammed
- Department of Chemistry, University of Oxford, Oxford, United Kingdom.,Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Carol V Robinson
- Department of Chemistry, University of Oxford, Oxford, United Kingdom
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Schmidt C, Beilsten-Edmands V, Robinson CV. Insights into Eukaryotic Translation Initiation from Mass Spectrometry of Macromolecular Protein Assemblies. J Mol Biol 2015; 428:344-356. [PMID: 26497764 DOI: 10.1016/j.jmb.2015.10.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Revised: 09/28/2015] [Accepted: 10/14/2015] [Indexed: 02/05/2023]
Abstract
Translation initiation in eukaryotes requires the interplay of at least 10 initiation factors that interact at the different steps of this phase of gene expression. The interactions of initiation factors and related proteins are in general controlled by phosphorylation, which serves as a regulatory switch to turn protein translation on or off. The structures of initiation factors and a complete description of their post-translational modification (PTM) status are therefore required in order to fully understand these processes. In recent years, mass spectrometry has contributed considerably to provide this information and nowadays is proving to be indispensable when studying dynamic heterogeneous protein complexes such as the eukaryotic initiation factors. Herein, we highlight mass spectrometric approaches commonly applied to identify interacting subunits and their PTMs and the structural techniques that allow the architecture of protein complexes to be assessed. We present recent structural investigations of initiation factors and their interactions with other factors and with ribosomes and we assess the models generated. These models allow us to locate PTMs within initiation factor complexes and to highlight possible roles for phosphorylation sites in regulating interaction interfaces.
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Affiliation(s)
- Carla Schmidt
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom.
| | - Victoria Beilsten-Edmands
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom.
| | - Carol V Robinson
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom.
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Rouillon C, Zhou M, Zhang J, Politis A, Beilsten-Edmands V, Cannone G, Graham S, Robinson CV, Spagnolo L, White MF. Structure of the CRISPR interference complex CSM reveals key similarities with cascade. Mol Cell 2013; 52:124-34. [PMID: 24119402 PMCID: PMC3807668 DOI: 10.1016/j.molcel.2013.08.020] [Citation(s) in RCA: 152] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Revised: 07/11/2013] [Accepted: 08/01/2013] [Indexed: 11/16/2022]
Abstract
The Clustered Regularly Interspaced Palindromic Repeats (CRISPR) system is an adaptive immune system in prokaryotes. Interference complexes encoded by CRISPR-associated (cas) genes utilize small RNAs for homology-directed detection and subsequent degradation of invading genetic elements, and they have been classified into three main types (I-III). Type III complexes share the Cas10 subunit but are subclassifed as type IIIA (CSM) and type IIIB (CMR), depending on their specificity for DNA or RNA targets, respectively. The role of CSM in limiting the spread of conjugative plasmids in Staphylococcus epidermidis was first described in 2008. Here, we report a detailed investigation of the composition and structure of the CSM complex from the archaeon Sulfolobus solfataricus, using a combination of electron microscopy, mass spectrometry, and deep sequencing. This reveals a three-dimensional model for the CSM complex that includes a helical component strikingly reminiscent of the backbone structure of the type I (Cascade) family.
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Affiliation(s)
- Christophe Rouillon
- Biomedical Sciences Research Complex, University of St Andrews, Fife KY16 9ST, UK
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