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Santander EA, Bravo G, Chang-Halabi Y, Olguín-Orellana GJ, Naulin PA, Barrera MJ, Montenegro FA, Barrera NP. The Adsorption of P2X2 Receptors Interacting with IgG Antibodies Revealed by Combined AFM Imaging and Mechanical Simulation. Int J Mol Sci 2023; 25:336. [PMID: 38203505 PMCID: PMC10778698 DOI: 10.3390/ijms25010336] [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: 10/30/2023] [Revised: 12/16/2023] [Accepted: 12/19/2023] [Indexed: 01/12/2024] Open
Abstract
The adsorption of proteins onto surfaces significantly impacts biomaterials, medical devices, and biological processes. This study aims to provide insights into the irreversible adsorption process of multiprotein complexes, particularly focusing on the interaction between anti-His6 IgG antibodies and the His6-tagged P2X2 receptor. Traditional approaches to understanding protein adsorption have centered around kinetic and thermodynamic models, often examining individual proteins and surface coverage, typically through Molecular Dynamics (MD) simulations. In this research, we introduce a computational approach employing Autodesk Maya 3D software for the investigation of multiprotein complexes' adsorption behavior. Utilizing Atomic Force Microscopy (AFM) imaging and Maya 3D-based mechanical simulations, our study yields real-time structural and kinetic observations. Our combined experimental and computational findings reveal that the P2X2 receptor-IgG antibody complex likely undergoes absorption in an 'extended' configuration. Whereas the P2X2 receptor is less adsorbed once is complexed to the IgG antibody compared to its individual state, the opposite is observed for the antibody. This insight enhances our understanding of the role of protein-protein interactions in the process of protein adsorption.
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Affiliation(s)
- Eduardo A. Santander
- Laboratory of Nanophysiology and Structural Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Alameda 340, Santiago 8331150, Chile; (E.A.S.); (G.B.); (G.J.O.-O.)
| | - Graciela Bravo
- Laboratory of Nanophysiology and Structural Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Alameda 340, Santiago 8331150, Chile; (E.A.S.); (G.B.); (G.J.O.-O.)
- Department of Chemical and Bioprocess Engineering, School of Engineering, Pontificia Universidad Católica de Chile, Santiago 7820436, Chile
| | - Yuan Chang-Halabi
- Laboratory of Nanophysiology and Structural Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Alameda 340, Santiago 8331150, Chile; (E.A.S.); (G.B.); (G.J.O.-O.)
| | - Gabriel J. Olguín-Orellana
- Laboratory of Nanophysiology and Structural Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Alameda 340, Santiago 8331150, Chile; (E.A.S.); (G.B.); (G.J.O.-O.)
| | - Pamela A. Naulin
- Laboratory of Nanophysiology and Structural Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Alameda 340, Santiago 8331150, Chile; (E.A.S.); (G.B.); (G.J.O.-O.)
| | - Mario J. Barrera
- Laboratory of Nanophysiology and Structural Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Alameda 340, Santiago 8331150, Chile; (E.A.S.); (G.B.); (G.J.O.-O.)
| | - Felipe A. Montenegro
- Laboratory of Nanophysiology and Structural Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Alameda 340, Santiago 8331150, Chile; (E.A.S.); (G.B.); (G.J.O.-O.)
| | - Nelson P. Barrera
- Laboratory of Nanophysiology and Structural Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Alameda 340, Santiago 8331150, Chile; (E.A.S.); (G.B.); (G.J.O.-O.)
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2
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Campuzano IDG. A Research Journey: Over a Decade of Denaturing and Native-MS Analyses of Hydrophobic and Membrane Proteins in Amgen Therapeutic Discovery. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2023; 34:2413-2431. [PMID: 37643331 DOI: 10.1021/jasms.3c00175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Membrane proteins and associated complexes currently comprise the majority of therapeutic targets and remain among the most challenging classes of proteins for analytical characterization. Through long-term strategic collaborations forged between industrial and academic research groups, there has been tremendous progress in advancing membrane protein mass spectrometry (MS) analytical methods and their concomitant application to Amgen therapeutic project progression. Herein, I will describe a detailed and personal account of how electrospray ionization (ESI) native mass spectrometry (nMS), ion mobility-MS (IM-MS), reversed phase liquid chromatographic mass spectrometry (RPLC-MS), high-throughput solid phase extraction mass spectrometry, and matrix-assisted laser desorption ionization mass spectrometry methods were developed, optimized, and validated within Amgen Research, and importantly, how these analytical methods were applied for membrane and hydrophobic protein analyses and ultimately therapeutic project support and progression. Additionally, I will discuss all the highly important and productive collaborative efforts, both internal Amgen and external academic, which were key in generating the samples, methods, and associated data described herein. I will also describe some early and previously unpublished nano-ESI (nESI) native-MS data from Amgen Research and the highly productive University of California Los Angeles (UCLA) collaboration. I will also present previously unpublished examples of real-life Amgen biotherapeutic membrane protein projects that were supported by all the MS (and IM) analytical techniques described herein. I will start by describing the initial nESI nMS experiments performed at Amgen in 2011 on empty nanodisc molecules, using a quadrupole time-of-flight MS, and how these experiments progressed on to the 15 Tesla Fourier transform ion cyclotron resonance MS at UCLA. Then described are monomeric and multimeric membrane protein data acquired in both nESI nMS and tandem-MS modes, using multiple methods of ion activation, resulting in dramatic spectral simplification. Also described is how we investigated the far less established and less published subject, that is denaturing RPLC-MS analysis of membrane proteins, and how we developed a highly robust and reproducible RPLC-MS method capable of effective separation of membrane proteins differing in only the presence or absence of an N-terminal post translational modification. Also described is the evolution of the aforementioned RPLC-MS method into a high-throughput solid phase extraction MS method. Finally, I will give my opinion on key developments and how the area of nMS of membrane proteins needs to evolve to a state where it can be applied within the biopharmaceutical research environment for routine therapeutic project support.
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Affiliation(s)
- Iain D G Campuzano
- Amgen Research, Center for Research Acceleration by Digital Innovation, Molecular Analytics, Thousand Oaks, California 91320, United States
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3
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Yen HY, Abramsson ML, Agasid MT, Lama D, Gault J, Liko I, Kaldmäe M, Saluri M, Qureshi AA, Suades A, Drew D, Degiacomi MT, Marklund EG, Allison TM, Robinson CV, Landreh M. Electrospray ionization of native membrane proteins proceeds via a charge equilibration step. RSC Adv 2022; 12:9671-9680. [PMID: 35424940 PMCID: PMC8972943 DOI: 10.1039/d2ra01282k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 03/21/2022] [Indexed: 11/21/2022] Open
Abstract
Electrospray ionization mass spectrometry is increasingly applied to study the structures and interactions of membrane protein complexes. However, the charging mechanism is complicated by the presence of detergent micelles during ionization. Here, we show that the final charge of membrane proteins can be predicted by their molecular weight when released from the non-charge reducing saccharide detergents. Our data indicate that PEG detergents lower the charge depending on the number of detergent molecules in the surrounding micelle, whereas fos-choline detergents may additionally participate in ion–ion reactions after desolvation. The supercharging reagent sulfolane, on the other hand, has no discernible effect on the charge of detergent-free membrane proteins. Taking our observations into the context of protein-detergent interactions in the gas phase, we propose a charge equilibration model for the generation of native-like membrane protein ions. During ionization of the protein-detergent complex, the ESI charges are distributed between detergent and protein according to proton affinity of the detergent, number of detergent molecules, and surface area of the protein. Charge equilibration influenced by detergents determines the final charge state of membrane proteins. This process likely contributes to maintaining a native-like fold after detergent release and can be harnessed to stabilize particularly labile membrane protein complexes in the gas phase. The electrospray ionization mechanism contributes to preserving the structures and interactions of membrane protein complexes in native mass spectrometry.![]()
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Affiliation(s)
- Hsin-Yung Yen
- Department of Chemistry, University of Oxford South Parks Road Oxford OX1 3QZ UK .,Institute of Biological Chemistry, Academia Sinica 128, Academia Road Sec. 2, Nankang Taipei 115 Taiwan
| | - Mia L Abramsson
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet Tomtebodavägen 23A 17165 Stockholm Sweden
| | - Mark T Agasid
- Department of Chemistry, University of Oxford South Parks Road Oxford OX1 3QZ UK
| | - Dilraj Lama
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet Tomtebodavägen 23A 17165 Stockholm Sweden
| | - Joseph Gault
- Department of Chemistry, University of Oxford South Parks Road Oxford OX1 3QZ UK
| | - Idlir Liko
- Department of Chemistry, University of Oxford South Parks Road Oxford OX1 3QZ UK
| | - Margit Kaldmäe
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet Tomtebodavägen 23A 17165 Stockholm Sweden
| | - Mihkel Saluri
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet Tomtebodavägen 23A 17165 Stockholm Sweden
| | - Abdul Aziz Qureshi
- Department of Chemistry, University of Oxford South Parks Road Oxford OX1 3QZ UK .,Department of Biochemistry and Biophysics, Stockholm University 10691 Stockholm Sweden
| | - Albert Suades
- Department of Biochemistry and Biophysics, Stockholm University 10691 Stockholm Sweden
| | - David Drew
- Department of Biochemistry and Biophysics, Stockholm University 10691 Stockholm Sweden
| | | | - Erik G Marklund
- Department of Chemistry - BMC, Uppsala University Box 576 75123 Uppsala Sweden
| | - Timothy M Allison
- Biomolecular Interaction Centre, School of Physical and Chemical Sciences, University of Canterbury Christchurch 8140 New Zealand
| | - Carol V Robinson
- Department of Chemistry, University of Oxford South Parks Road Oxford OX1 3QZ UK
| | - Michael Landreh
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet Tomtebodavägen 23A 17165 Stockholm Sweden
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Protein Lipidation Types: Current Strategies for Enrichment and Characterization. Int J Mol Sci 2022; 23:ijms23042365. [PMID: 35216483 PMCID: PMC8880637 DOI: 10.3390/ijms23042365] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 02/18/2022] [Accepted: 02/18/2022] [Indexed: 12/04/2022] Open
Abstract
Post-translational modifications regulate diverse activities of a colossal number of proteins. For example, various types of lipids can be covalently linked to proteins enzymatically or non-enzymatically. Protein lipidation is perhaps not as extensively studied as protein phosphorylation, ubiquitination, or glycosylation although it is no less significant than these modifications. Evidence suggests that proteins can be attached by at least seven types of lipids, including fatty acids, lipoic acids, isoprenoids, sterols, phospholipids, glycosylphosphatidylinositol anchors, and lipid-derived electrophiles. In this review, we summarize types of protein lipidation and methods used for their detection, with an emphasis on the conjugation of proteins with polyunsaturated fatty acids (PUFAs). We discuss possible reasons for the scarcity of reports on PUFA-modified proteins, limitations in current methodology, and potential approaches in detecting PUFA modifications.
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5
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Scratching the surface: native mass spectrometry of peripheral membrane protein complexes. Biochem Soc Trans 2021; 48:547-558. [PMID: 32129823 PMCID: PMC7192793 DOI: 10.1042/bst20190787] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 02/09/2020] [Accepted: 02/11/2020] [Indexed: 02/06/2023]
Abstract
A growing number of integral membrane proteins have been shown to tune their activity by selectively interacting with specific lipids. The ability to regulate biological functions via lipid interactions extends to the diverse group of proteins that associate only peripherally with the lipid bilayer. However, the structural basis of these interactions remains challenging to study due to their transient and promiscuous nature. Recently, native mass spectrometry has come into focus as a new tool to investigate lipid interactions in membrane proteins. Here, we outline how the native MS strategies developed for integral membrane proteins can be applied to generate insights into the structure and function of peripheral membrane proteins. Specifically, native MS studies of proteins in complex with detergent-solubilized lipids, bound to lipid nanodiscs, and released from native-like lipid vesicles all shed new light on the role of lipid interactions. The unique ability of native MS to capture and interrogate protein–protein, protein–ligand, and protein–lipid interactions opens exciting new avenues for the study of peripheral membrane protein biology.
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6
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Petroff JT, Tong A, Chen LJ, Dekoster GT, Khan F, Abramson J, Frieden C, Cheng WWL. Charge Reduction of Membrane Proteins in Native Mass Spectrometry Using Alkali Metal Acetate Salts. Anal Chem 2020; 92:6622-6630. [PMID: 32250604 DOI: 10.1021/acs.analchem.0c00454] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Native mass spectrometry (MS) provides the capacity to monitor membrane protein complexes and noncovalent binding of ligands and lipids to membrane proteins. The charge states produced by native MS of membrane proteins often result in gas-phase protein unfolding or loss of noncovalent interactions. In an effort to reduce the charge of membrane proteins, we examined the utility of alkali metal salts as a charge-reducing agent. Low concentrations of alkali metal salts caused marked charge reduction in the membrane protein, Erwinia ligand-gated ion channel (ELIC). The charge-reducing effect only occurred for membrane proteins and was detergent-dependent, being most pronounced in long polyethylene glycol (PEG)-based detergents such as C10E5 and C12E8. On the basis of these results, we propose a mechanism for alkali metal charge reduction of membrane proteins. Addition of low concentrations of alkali metals may provide an advantageous approach for charge reduction of detergent-solubilized membrane proteins by native MS.
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Affiliation(s)
| | | | | | | | - Farha Khan
- Department of Physiology, David Geffen School of Medicine at UCLA, 310833 Le Conte Avenue, Los Angeles, California 90095, United States
| | - Jeff Abramson
- Department of Physiology, David Geffen School of Medicine at UCLA, 310833 Le Conte Avenue, Los Angeles, California 90095, United States
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7
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Peetz O, Hellwig N, Henrich E, Mezhyrova J, Dötsch V, Bernhard F, Morgner N. LILBID and nESI: Different Native Mass Spectrometry Techniques as Tools in Structural Biology. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2019; 30:181-191. [PMID: 30225732 PMCID: PMC6318263 DOI: 10.1007/s13361-018-2061-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 08/02/2018] [Accepted: 08/08/2018] [Indexed: 06/08/2023]
Abstract
Native mass spectrometry is applied for the investigation of proteins and protein complexes worldwide. The challenge in native mass spectrometry is maintaining the features of the proteins of interest, such as oligomeric state, bound ligands, or the conformation of the protein complex, during transfer from solution to gas phase. This is an essential prerequisite to allow conclusions about the solution state protein complex, based on the gas phase measurements. Therefore, soft ionization techniques are required. Widely used for the analysis of protein complexes are nanoelectro spray ionization (nESI) mass spectrometers. A newer ionization method is laser induced liquid bead ion desorption (LILBID), which is based on the release of protein complexes from solution phase via infrared (IR) laser desorption. We use both methods in our lab, depending on the requirements of the biological system we are interested in. Here we benchmark the performance of our LILBID mass spectrometer in comparison to a nESI instrument, regarding sample conditions, buffer and additive tolerances, dissociation mechanism and applicability towards soluble and membrane protein complexes. Graphical Abstract ᅟ.
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Affiliation(s)
- Oliver Peetz
- Institute of Physical and Theoretical Chemistry, J.W. Goethe-University, Frankfurt am Main, Germany
| | - Nils Hellwig
- Institute of Physical and Theoretical Chemistry, J.W. Goethe-University, Frankfurt am Main, Germany
| | - Erik Henrich
- Institute of Biophysical Chemistry, Centre for Biomolecular Magnetic Resonance, J.W. Goethe-University, Frankfurt am Main, Germany
| | - Julija Mezhyrova
- Institute of Biophysical Chemistry, Centre for Biomolecular Magnetic Resonance, J.W. Goethe-University, Frankfurt am Main, Germany
| | - Volker Dötsch
- Institute of Biophysical Chemistry, Centre for Biomolecular Magnetic Resonance, J.W. Goethe-University, Frankfurt am Main, Germany
| | - Frank Bernhard
- Institute of Biophysical Chemistry, Centre for Biomolecular Magnetic Resonance, J.W. Goethe-University, Frankfurt am Main, Germany
| | - Nina Morgner
- Institute of Physical and Theoretical Chemistry, J.W. Goethe-University, Frankfurt am Main, Germany.
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8
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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: 142] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [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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9
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Abstract
Outer-membrane porins are often considered as passive conduits of small molecules across lipid bilayers. Using native mass spectrometry experiments we identify a pH-sensitive lipid-binding mechanism of outer membrane porin F, which enables increased threading of a colicin-derived peptide through open channels. Supported by molecular dynamics simulations and channel recording experiments, we posit that this mechanism attenuates channel opening in response to changes in environmental conditions, specifically pH. These findings have important consequences for mass spectrometry experiments, wherein the role of charge is often overlooked, and they also could help provide understanding of antibiotics that gain access to Gram-negative bacteria through porin-mediated pathways. Strong interactions between lipids and proteins occur primarily through association of charged headgroups and amino acid side chains, rendering the protonation status of both partners important. Here we use native mass spectrometry to explore lipid binding as a function of charge of the outer membrane porin F (OmpF). We find that binding of anionic phosphatidylglycerol (POPG) or zwitterionic phosphatidylcholine (POPC) to OmpF is sensitive to electrospray polarity while the effects of charge are less pronounced for other proteins in outer or mitochondrial membranes: the ferripyoverdine receptor (FpvA) or the voltage-dependent anion channel (VDAC). Only marginal charge-induced differences were observed for inner membrane proteins: the ammonia channel (AmtB) or the mechanosensitive channel. To understand these different sensitivities, we performed an extensive bioinformatics analysis of membrane protein structures and found that OmpF, and to a lesser extent FpvA and VDAC, have atypically high local densities of basic and acidic residues in their lipid headgroup-binding regions. Coarse-grained molecular dynamics simulations, in mixed lipid bilayers, further implicate changes in charge by demonstrating preferential binding of anionic POPG over zwitterionic POPC to protonated OmpF, an effect not observed to the same extent for AmtB. Moreover, electrophysiology and mass-spectrometry–based ligand-binding experiments, at low pH, show that POPG can maintain OmpF channels in open conformations for extended time periods. Since the outer membrane is composed almost entirely of anionic lipopolysaccharide, with similar headgroup properties to POPG, such anionic lipid binding could prevent closure of OmpF channels, thereby increasing access of antibiotics that use porin-mediated pathways.
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10
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Montenegro FA, Cantero JR, Barrera NP. Combining Mass Spectrometry and X-Ray Crystallography for Analyzing Native-Like Membrane Protein Lipid Complexes. Front Physiol 2017; 8:892. [PMID: 29170643 PMCID: PMC5684187 DOI: 10.3389/fphys.2017.00892] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Accepted: 10/24/2017] [Indexed: 01/22/2023] Open
Abstract
Membrane proteins represent a challenging family of macromolecules, particularly related to the methodology aimed at characterizing their three-dimensional structure. This is mostly due to their amphipathic nature as well as requirements of ligand bindings to stabilize or control their function. Recently, Mass Spectrometry (MS) has become an important tool to identify the overall stoichiometry of native-like membrane proteins complexed to ligand bindings as well as to provide insights into the transport mechanism across the membrane, with complementary information coming from X-ray crystallography. This perspective article emphasizes MS findings coupled with X-ray crystallography in several membrane protein lipid complexes, in particular transporters, ion channels and molecular machines, with an overview of techniques that allows a more thorough structural interpretation of the results, which can help us to unravel hidden mysteries on the membrane protein function.
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Affiliation(s)
- Felipe A Montenegro
- Laboratory of Nanophysiology and Structural Biology, Department of Physiology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Jorge R Cantero
- Laboratory of Nanophysiology and Structural Biology, Department of Physiology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Nelson P Barrera
- Laboratory of Nanophysiology and Structural Biology, Department of Physiology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
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11
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Macek P, Kerfah R, Boeri Erba E, Crublet E, Moriscot C, Schoehn G, Amero C, Boisbouvier J. Unraveling self-assembly pathways of the 468-kDa proteolytic machine TET2. SCIENCE ADVANCES 2017; 3:e1601601. [PMID: 28435872 PMCID: PMC5384809 DOI: 10.1126/sciadv.1601601] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 02/10/2017] [Indexed: 05/03/2023]
Abstract
The spontaneous formation of biological higher-order structures from smaller building blocks, called self-assembly, is a fundamental attribute of life. Although the protein self-assembly is a time-dependent process that occurs at the molecular level, its current understanding originates either from static structures of trapped intermediates or from modeling. Nuclear magnetic resonance (NMR) spectroscopy has the unique ability to monitor structural changes in real time; however, its size limitation and time-resolution constraints remain a challenge when studying the self-assembly of large biological particles. We report the application of methyl-specific isotopic labeling combined with relaxation-optimized NMR spectroscopy to overcome both size- and time-scale limitations. We report for the first time the self-assembly process of a half-megadalton protein complex that was monitored at the structural level, including the characterization of intermediate states, using a mutagenesis-free strategy. NMR was used to obtain individual kinetics data on the different transient intermediates and the formation of final native particle. In addition, complementary time-resolved electron microscopy and native mass spectrometry were used to characterize the low-resolution structures of oligomerization intermediates.
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Affiliation(s)
- Pavel Macek
- Université Grenoble Alpes, Institut de
Biologie Structurale (IBS), Grenoble, France
- CEA, IBS, Grenoble, France
- CNRS, IBS, Grenoble, France
| | - Rime Kerfah
- Université Grenoble Alpes, Institut de
Biologie Structurale (IBS), Grenoble, France
- CEA, IBS, Grenoble, France
- CNRS, IBS, Grenoble, France
| | - Elisabetta Boeri Erba
- Université Grenoble Alpes, Institut de
Biologie Structurale (IBS), Grenoble, France
- CEA, IBS, Grenoble, France
- CNRS, IBS, Grenoble, France
| | - Elodie Crublet
- Université Grenoble Alpes, Institut de
Biologie Structurale (IBS), Grenoble, France
- CEA, IBS, Grenoble, France
- CNRS, IBS, Grenoble, France
| | - Christine Moriscot
- Université Grenoble Alpes, Institut de
Biologie Structurale (IBS), Grenoble, France
- CEA, IBS, Grenoble, France
- CNRS, IBS, Grenoble, France
| | - Guy Schoehn
- Université Grenoble Alpes, Institut de
Biologie Structurale (IBS), Grenoble, France
- CEA, IBS, Grenoble, France
- CNRS, IBS, Grenoble, France
| | - Carlos Amero
- Centro de Investigaciones Químicas, IICBA,
Universidad Autónoma del Estado de Morelos, México
- Corresponding author. (C.A.);
(J.B.)
| | - Jerome Boisbouvier
- Université Grenoble Alpes, Institut de
Biologie Structurale (IBS), Grenoble, France
- CEA, IBS, Grenoble, France
- CNRS, IBS, Grenoble, France
- Corresponding author. (C.A.);
(J.B.)
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12
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Probing the dynamic regulation of peripheral membrane proteins using hydrogen deuterium exchange-MS (HDX-MS). Biochem Soc Trans 2016; 43:773-86. [PMID: 26517882 DOI: 10.1042/bst20150065] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Many cellular signalling events are controlled by the selective recruitment of protein complexes to membranes. Determining the molecular basis for how lipid signalling complexes are recruited, assembled and regulated on specific membrane compartments has remained challenging due to the difficulty of working in conditions mimicking native biological membrane environments. Enzyme recruitment to membranes is controlled by a variety of regulatory mechanisms, including binding to specific lipid species, protein-protein interactions, membrane curvature, as well as post-translational modifications. A powerful tool to study the regulation of membrane signalling enzymes and complexes is hydrogen deuterium exchange-MS (HDX-MS), a technique that allows for the interrogation of protein dynamics upon membrane binding and recruitment. This review will highlight the theory and development of HDX-MS and its application to examine the molecular basis of lipid signalling enzymes, specifically the regulation and activation of phosphoinositide 3-kinases (PI3Ks).
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13
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Allison TM, Landreh M, Benesch JLP, Robinson CV. Low Charge and Reduced Mobility of Membrane Protein Complexes Has Implications for Calibration of Collision Cross Section Measurements. Anal Chem 2016; 88:5879-5884. [PMID: 27153188 DOI: 10.1021/acs.analchem.6b00691] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Ion mobility mass spectrometry of integral membrane proteins provides valuable insights into their architecture and stability. Here we show that, due to their lower charge, the average mobility of native-like membrane protein ions is approximately 30% lower than that of soluble proteins of similar mass. This has implications for drift time measurements, made on traveling wave ion mobility mass spectrometers, which have to be calibrated to extract collision cross sections (Ω). Common calibration strategies employ unfolded or native-like soluble protein standards with masses and mobilities comparable to the protein of interest. We compare Ω values for membrane proteins, derived from standard calibration protocols using soluble proteins, to values measured using an RF-confined drift tube. Our results demonstrate that, while common calibration methods underestimate Ω for native-like or unfolded membrane protein complexes, higher mass soluble calibration standards consistently yield more accurate Ω values. These findings enable us to obtain directly structural information for highly charge-reduced complexes by traveling wave ion mobility mass spectrometry.
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Affiliation(s)
- Timothy M Allison
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QZ, United Kingdom
| | - Michael Landreh
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QZ, United Kingdom
| | - Justin L P Benesch
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QZ, United Kingdom
| | - Carol V Robinson
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QZ, United Kingdom
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14
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Wessels HJCT, de Almeida NM, Kartal B, Keltjens JT. Bacterial Electron Transfer Chains Primed by Proteomics. Adv Microb Physiol 2016; 68:219-352. [PMID: 27134025 DOI: 10.1016/bs.ampbs.2016.02.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Electron transport phosphorylation is the central mechanism for most prokaryotic species to harvest energy released in the respiration of their substrates as ATP. Microorganisms have evolved incredible variations on this principle, most of these we perhaps do not know, considering that only a fraction of the microbial richness is known. Besides these variations, microbial species may show substantial versatility in using respiratory systems. In connection herewith, regulatory mechanisms control the expression of these respiratory enzyme systems and their assembly at the translational and posttranslational levels, to optimally accommodate changes in the supply of their energy substrates. Here, we present an overview of methods and techniques from the field of proteomics to explore bacterial electron transfer chains and their regulation at levels ranging from the whole organism down to the Ångstrom scales of protein structures. From the survey of the literature on this subject, it is concluded that proteomics, indeed, has substantially contributed to our comprehending of bacterial respiratory mechanisms, often in elegant combinations with genetic and biochemical approaches. However, we also note that advanced proteomics offers a wealth of opportunities, which have not been exploited at all, or at best underexploited in hypothesis-driving and hypothesis-driven research on bacterial bioenergetics. Examples obtained from the related area of mitochondrial oxidative phosphorylation research, where the application of advanced proteomics is more common, may illustrate these opportunities.
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Affiliation(s)
- H J C T Wessels
- Nijmegen Center for Mitochondrial Disorders, Radboud Proteomics Centre, Translational Metabolic Laboratory, Radboud University Medical Center, Nijmegen, The Netherlands
| | - N M de Almeida
- Institute of Water and Wetland Research, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - B Kartal
- Institute of Water and Wetland Research, Radboud University Nijmegen, Nijmegen, The Netherlands; Laboratory of Microbiology, Ghent University, Ghent, Belgium
| | - J T Keltjens
- Institute of Water and Wetland Research, Radboud University Nijmegen, Nijmegen, The Netherlands.
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15
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Reading E, Liko I, Allison TM, Benesch JLP, Laganowsky A, Robinson CV. The Role of the Detergent Micelle in Preserving the Structure of Membrane Proteins in the Gas Phase. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201411622] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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16
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Reading E, Liko I, Allison TM, Benesch JLP, Laganowsky A, Robinson CV. The role of the detergent micelle in preserving the structure of membrane proteins in the gas phase. Angew Chem Int Ed Engl 2015; 54:4577-81. [PMID: 25693501 DOI: 10.1002/anie.201411622] [Citation(s) in RCA: 104] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Indexed: 11/12/2022]
Abstract
Despite the growing importance of the mass spectrometry of membrane proteins, it is not known how their transfer from solution into vacuum affects their stability and structure. To address this we have carried out a systematic investigation of ten membrane proteins solubilized in different detergents and used mass spectrometry to gain physicochemical insight into the mechanism of their ionization and desolvation. We show that the chemical properties of the detergents mediate the charge state, both during ionization and detergent removal. Using ion mobility mass spectrometry, we monitor the conformations of membrane proteins and show how the surface charge density dictates the stability of folded states. We conclude that the gas-phase stability of membrane proteins is increased when a greater proportion of their surface is lipophilic and is consequently protected by the physical presence of the micelle.
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Affiliation(s)
- Eamonn Reading
- Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, OX1 3QZ (UK)
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17
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Mehmood S, Marcoux J, Hopper JTS, Allison TM, Liko I, Borysik AJ, Robinson CV. Charge reduction stabilizes intact membrane protein complexes for mass spectrometry. J Am Chem Soc 2014; 136:17010-2. [PMID: 25402655 DOI: 10.1021/ja510283g] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The study of intact soluble protein assemblies by means of mass spectrometry is providing invaluable contributions to structural biology and biochemistry. A recent breakthrough has enabled similar study of membrane protein complexes, following their release from detergent micelles in the gas phase. Careful optimization of mass spectrometry conditions, particularly with respect to energy regimes, is essential for maintaining compact folded states as detergent is removed. However, many of the saccharide detergents widely employed in structural biology can cause unfolding of membrane proteins in the gas phase. Here, we investigate the potential of charge reduction by introducing three membrane protein complexes from saccharide detergents and show how reducing their overall charge enables generation of compact states, as evidenced by ion mobility mass spectrometry. We find that charge reduction stabilizes the oligomeric state and enhances the stability of lipid-bound complexes. This finding is significant since maintaining native-like membrane proteins enables ligand binding to be assessed from a range of detergents that retain solubility while protecting the overall fold.
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Affiliation(s)
- Shahid Mehmood
- Department of Chemistry, University of Oxford , Oxford, U.K
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18
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Ma X, Lai LB, Lai SM, Tanimoto A, Foster MP, Wysocki VH, Gopalan V. Uncovering the Stoichiometry of Pyrococcus furiosusRNase P, a Multi-Subunit Catalytic Ribonucleoprotein Complex, by Surface-Induced Dissociation and Ion Mobility Mass Spectrometry. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201405362] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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19
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Ma X, Lai LB, Lai SM, Tanimoto A, Foster MP, Wysocki VH, Gopalan V. Uncovering the stoichiometry of Pyrococcus furiosus RNase P, a multi-subunit catalytic ribonucleoprotein complex, by surface-induced dissociation and ion mobility mass spectrometry. Angew Chem Int Ed Engl 2014; 53:11483-7. [PMID: 25195671 DOI: 10.1002/anie.201405362] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Revised: 07/16/2014] [Indexed: 01/02/2023]
Abstract
We demonstrate that surface-induced dissociation (SID) coupled with ion mobility mass spectrometry (IM-MS) is a powerful tool for determining the stoichiometry of a multi-subunit ribonucleoprotein (RNP) complex assembled in a solution containing Mg(2+). We investigated Pyrococcus furiosus (Pfu) RNase P, an archaeal RNP that catalyzes tRNA 5' maturation. Previous step-wise, Mg(2+)-dependent reconstitutions of Pfu RNase P with its catalytic RNA subunit and two interacting protein cofactor pairs (RPP21⋅RPP29 and POP5⋅RPP30) revealed functional RNP intermediates en route to the RNase P enzyme, but provided no information on subunit stoichiometry. Our native MS studies with the proteins showed RPP21⋅RPP29 and (POP5⋅RPP30)2 complexes, but indicated a 1:1 composition for all subunits when either one or both protein complexes bind the cognate RNA. These results highlight the utility of SID and IM-MS in resolving conformational heterogeneity and yielding insights on RNP assembly.
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Affiliation(s)
- Xin Ma
- Department of Chemistry and Biochemistry, Center for RNA Biology, The Ohio State University, Columbus, OH 43210 (USA)
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20
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Snijder J, van de
Waterbeemd M, Damoc E, Denisov E, Grinfeld D, Bennett A, Agbandje-McKenna M, Makarov A, Heck AJR. Defining the stoichiometry and cargo load of viral and bacterial nanoparticles by Orbitrap mass spectrometry. J Am Chem Soc 2014; 136:7295-9. [PMID: 24787140 PMCID: PMC4046769 DOI: 10.1021/ja502616y] [Citation(s) in RCA: 123] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Revised: 03/14/2014] [Indexed: 12/12/2022]
Abstract
Accurate mass analysis can provide useful information on the stoichiometry and composition of protein-based particles, such as virus-like assemblies. For applications in nanotechnology and medicine, such nanoparticles are loaded with foreign cargos, making accurate mass information essential to define the cargo load. Here, we describe modifications to an Orbitrap mass spectrometer that enable high mass analysis of several virus-like nanoparticles up to 4.5 MDa in mass. This allows the accurate determination of the composition of virus-like particles. The modified instrument is utilized to determine the cargo load of bacterial encapsulin nanoparticles that were engineered to encapsulate foreign cargo proteins. We find that encapsulin packages from 8 up to 12 cargo proteins, thereby quantifying cargo load but also showing the ensemble spread. In addition, we determined the previously unknown stoichiometry of the three different splice variants of the capsid protein in adeno-associated virus (AAV) capsids, showing that symmetry is broken and assembly is heterogeneous and stochastic. These results demonstrate the potential of high-resolution mass analysis of protein-based nanoparticles, with widespread applications in chemical biology and nanotechnology.
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Affiliation(s)
- Joost Snijder
- 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
| | - Michiel van de
Waterbeemd
- 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
| | - Eugen Damoc
- Thermo
Fisher Scientific (Bremen), Bremen 28199, Germany
| | - Eduard Denisov
- Thermo
Fisher Scientific (Bremen), Bremen 28199, Germany
| | | | - Antonette Bennett
- Department
of Biochemistry and Molecular Biology, Center for Structural Biology,
McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida 32610, United States
| | - Mavis Agbandje-McKenna
- Department
of Biochemistry and Molecular Biology, Center for Structural Biology,
McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida 32610, United States
| | - Alexander Makarov
- 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
- Thermo
Fisher Scientific (Bremen), Bremen 28199, Germany
| | - 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
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21
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Roberts KM, Tormos JR, Fitzpatrick PF. Characterization of unstable products of flavin- and pterin-dependent enzymes by continuous-flow mass spectrometry. Biochemistry 2014; 53:2672-9. [PMID: 24713088 PMCID: PMC4010283 DOI: 10.1021/bi500267c] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
![]()
Continuous-flow mass spectrometry
(CFMS) was used to monitor the
products formed during the initial 0.25–20 s of the reactions
catalyzed by the flavoprotein N-acetylpolyamine oxidase
(PAO) and the pterin-dependent enzymes phenylalanine hydroxylase (PheH)
and tyrosine hydroxylase (TyrH). N,N′-Dibenzyl-1,4-diaminobutane (DBDB) is a substrate for PAO
for which amine oxidation is rate-limiting. CFMS of the reaction showed
formation of an initial imine due to oxidation of an exo-carbon–nitrogen bond. Nonenzymatic hydrolysis of the imine
formed benzaldehyde and N-benzyl-1,4-diaminobutane;
the subsequent oxidation by PAO of the latter to an additional imine
could also be followed. Measurement of the deuterium kinetic isotope
effect on DBDB oxidation by CFMS yielded a value of 7.6 ± 0.3,
in good agreement with a value of 6.7 ± 0.6 from steady-state
kinetic analyses. In the PheH reaction, the transient formation of
the 4a-hydroxypterin product was readily detected; tandem mass spectrometry
confirmed attachment of the oxygen to C(4a). With wild-type TyrH,
the 4a-hydroxypterin was also the product. In contrast, no product
other than a dihydropterin could be detected in the reaction of the
mutant protein E332A TyrH.
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Affiliation(s)
- Kenneth M Roberts
- Department of Biochemistry, University of Texas Health Science Center , San Antonio, Texas 78229, United States
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22
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Zhou M, Politis A, Davies R, Liko I, Wu KJ, Stewart AG, Stock D, Robinson CV. Ion mobility-mass spectrometry of a rotary ATPase reveals ATP-induced reduction in conformational flexibility. Nat Chem 2014; 6:208-215. [PMID: 24557135 PMCID: PMC4067995 DOI: 10.1038/nchem.1868] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Accepted: 01/08/2014] [Indexed: 12/20/2022]
Abstract
Rotary ATPases play fundamental roles in energy conversion as their catalytic rotation is associated with interdomain fluctuations and heterogeneity of conformational states. Using ion mobility mass spectrometry we compared the conformational dynamics of the intact ATPase from Thermus thermophilus with those of its membrane and soluble subcomplexes. Our results define regions with enhanced flexibility assigned to distinct subunits within the overall assembly. To provide a structural context for our experimental data we performed molecular dynamics simulations and observed conformational changes of the peripheral stalks that reflect their intrinsic flexibility. By isolating complexes at different phases of cell growth and manipulating nucleotides, metal ions and pH during isolation, we reveal differences that can be related to conformational changes in the Vo complex triggered by ATP binding. Together these results implicate nucleotides in modulating flexibility of the stator components and uncover mechanistic detail that underlies operation and regulation in the context of the holoenzyme.
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Affiliation(s)
- Min Zhou
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ, UK
| | - Argyris Politis
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ, UK
| | - Roberta Davies
- The Victor Chang Cardiac Research Institute, Darlinghurst NSW 2010, Australia
- The University of New South Wales, Sydney NSW 2052, Australia
| | - Idlir Liko
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ, UK
| | - Kuan-Jung Wu
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ, UK
| | - Alastair G Stewart
- The Victor Chang Cardiac Research Institute, Darlinghurst NSW 2010, Australia
- The University of New South Wales, Sydney NSW 2052, Australia
| | - Daniela Stock
- The Victor Chang Cardiac Research Institute, Darlinghurst NSW 2010, Australia
- The University of New South Wales, Sydney NSW 2052, Australia
| | - Carol V Robinson
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ, UK
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23
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Koshy SS, Eyles SJ, Weis RM, Thompson LK. Hydrogen exchange mass spectrometry of functional membrane-bound chemotaxis receptor complexes. Biochemistry 2013; 52:8833-42. [PMID: 24274333 DOI: 10.1021/bi401261b] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The transmembrane signaling mechanism of bacterial chemotaxis receptors is thought to involve changes in receptor conformation and dynamics. The receptors function in ternary complexes with two other proteins, CheA and CheW, that form extended membrane-bound arrays. Previous studies have shown that attractant binding induces a small (∼2 Å) piston displacement of one helix of the periplasmic and transmembrane domains toward the cytoplasm, but it is not clear how this signal propagates through the cytoplasmic domain to control the kinase activity of the CheA bound at the membrane-distal tip, nearly 200 Å away. The cytoplasmic domain has been shown to be highly dynamic, which raises the question of how a small piston motion could propagate through a dynamic domain to control CheA kinase activity. To address this, we have developed a method for measuring dynamics of the receptor cytoplasmic fragment (CF) in functional complexes with CheA and CheW. Hydrogen-deuterium exchange mass spectrometry (HDX-MS) measurements of global exchange of the CF demonstrate that the CF exhibits significantly slower exchange in functional complexes than in solution. Because the exchange rates in functional complexes are comparable to those of other proteins with similar structures, the CF appears to be a well-structured protein within these complexes, which is compatible with its role in propagating a signal that appears to be a tiny conformational change in the periplasmic and transmembrane domains of the receptor. We also demonstrate the feasibility of this protocol for local exchange measurements by incorporating a pepsin digest step to produce peptides with 87% sequence coverage and only 20% back exchange. This method extends HDX-MS to membrane-bound functional complexes without detergents that may perturb the stability or structure of the system.
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Affiliation(s)
- Seena S Koshy
- Department of Chemistry, ‡Department of Biochemistry and Molecular Biology, and §Program in Molecular and Cellular Biology, University of Massachusetts , Amherst, Massachusetts 01003, United States
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24
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Zhang H, Cui W, Gross ML. Native electrospray ionization and electron-capture dissociation for comparison of protein structure in solution and the gas phase. INTERNATIONAL JOURNAL OF MASS SPECTROMETRY 2013; 354-355:10.1016/j.ijms.2013.06.019. [PMID: 24363606 PMCID: PMC3867139 DOI: 10.1016/j.ijms.2013.06.019] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The importance of protein and protein-complex structure motivates improvements in speed and sensitivity of structure determination in the gas phase and comparison with that in solution or solid state. An opportunity for the gas phase measurement is mass spectrometry (MS) combined with native electrospray ionization (ESI), which delivers large proteins and protein complexes in their near-native states to the gas phase. In this communication, we describe the combination of native ESI, electron-capture dissociation (ECD), and top-down MS for exploring the structures of ubiquitin and cytochrome c in the gas phase and their relation to those in the solid-state and solution. We probe structure by comparing the protein's flexible regions, as predicted by the B-factor in X-ray crystallography, with the ECD fragments. The underlying hypothesis is that maintenance of structure gives fragments that can be predicted from B-factors. This strategy may be applicable in general when X-ray structures are available and extendable to the study of intrinsically disordered proteins.
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Affiliation(s)
- Hao Zhang
- Department of Chemistry, Washington University, St. Louis, Missouri, 63130 USA
| | - Weidong Cui
- Department of Chemistry, Washington University, St. Louis, Missouri, 63130 USA
| | - Michael L Gross
- Department of Chemistry, Washington University, St. Louis, Missouri, 63130 USA
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25
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Zhang N, Gordiyenko Y, Joly N, Lawton E, Robinson CV, Buck M. Subunit dynamics and nucleotide-dependent asymmetry of an AAA(+) transcription complex. J Mol Biol 2013; 426:71-83. [PMID: 24055699 DOI: 10.1016/j.jmb.2013.08.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Revised: 08/21/2013] [Accepted: 08/24/2013] [Indexed: 01/22/2023]
Abstract
Bacterial enhancer binding proteins (bEBPs) are transcription activators that belong to the AAA(+) protein family. They form higher-order self-assemblies to regulate transcription initiation at stress response and pathogenic promoters. The precise mechanism by which these ATPases utilize ATP binding and hydrolysis energy to remodel their substrates remains unclear. Here we employed mass spectrometry of intact complexes to investigate subunit dynamics and nucleotide occupancy of the AAA(+) domain of one well-studied bEBP in complex with its substrate, the σ(54) subunit of RNA polymerase. Our results demonstrate that the free AAA(+) domain undergoes significant changes in oligomeric states and nucleotide occupancy upon σ(54) binding. Such changes likely correlate with one transition state of ATP and are associated with an open spiral ring formation that is vital for asymmetric subunit function and interface communication. We confirmed that the asymmetric subunit functionality persists for open promoter complex formation using single-chain forms of bEBP lacking the full complement of intact ATP hydrolysis sites. Outcomes reconcile low- and high-resolution structures and yield a partial sequential ATP hydrolysis model for bEBPs.
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Affiliation(s)
- Nan Zhang
- Division of Cell and Molecular Biology, Sir Alexander Fleming Building, Imperial College London, Exhibition Road, London SW7 2AZ, UK.
| | - Yuliya Gordiyenko
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, UK
| | - Nicolas Joly
- Institut Jacques Monod, CNRS UMR 7592, Université Paris Diderot, Batiment Buffon, 15 rue Helene Brion, 75205 Paris Cedex 13, France
| | - Edward Lawton
- Division of Cell and Molecular Biology, Sir Alexander Fleming Building, Imperial College London, Exhibition Road, London SW7 2AZ, UK
| | - Carol V Robinson
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, UK.
| | - Martin Buck
- Division of Cell and Molecular Biology, Sir Alexander Fleming Building, Imperial College London, Exhibition Road, London SW7 2AZ, UK.
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26
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Schmidt C, Zhou M, Marriott H, Morgner N, Politis A, Robinson CV. Comparative cross-linking and mass spectrometry of an intact F-type ATPase suggest a role for phosphorylation. Nat Commun 2013; 4:1985. [PMID: 23756419 PMCID: PMC3709506 DOI: 10.1038/ncomms2985] [Citation(s) in RCA: 117] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Accepted: 05/07/2013] [Indexed: 11/13/2022] Open
Abstract
F-type ATPases are highly conserved enzymes used primarily for the synthesis of ATP. Here we apply mass spectrometry to the F1FO-ATPase, isolated from spinach chloroplasts, and uncover multiple modifications in soluble and membrane subunits. Mass spectra of the intact ATPase define a stable lipid 'plug' in the FO complex and reveal the stoichiometry of nucleotide binding in the F1 head. Comparing complexes formed in solution from an untreated ATPase with one incubated with a phosphatase reveals that the dephosphorylated enzyme has reduced nucleotide occupancy and decreased stability. By contrasting chemical cross-linking of untreated and dephosphorylated forms we show that cross-links are retained between the head and base, but are significantly reduced in the head, stators and stalk. Conformational changes at the catalytic interface, evidenced by changes in cross-linking, provide a rationale for reduced nucleotide occupancy and highlight a role for phosphorylation in regulating nucleotide binding and stability of the chloroplast ATPase.
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Affiliation(s)
- Carla Schmidt
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ, UK
| | - Min Zhou
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ, UK
| | - Hazel Marriott
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ, UK
| | - Nina Morgner
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ, UK
| | - Argyris Politis
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ, UK
| | - Carol V. Robinson
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ, UK
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