1
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Polák M, Černý J, Novák P. Isotopic Depletion Increases the Spatial Resolution of FPOP Top-Down Mass Spectrometry Analysis. Anal Chem 2024; 96:1478-1487. [PMID: 38226459 PMCID: PMC10831798 DOI: 10.1021/acs.analchem.3c03759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 11/08/2023] [Accepted: 12/15/2023] [Indexed: 01/17/2024]
Abstract
Protein radical labeling, like fast photochemical oxidation of proteins (FPOP), coupled to a top-down mass spectrometry (MS) analysis offers an alternative analytical method for probing protein structure or protein interaction with other biomolecules, for instance, proteins and DNA. However, with the increasing mass of studied analytes, the MS/MS spectra become complex and exhibit a low signal-to-noise ratio. Nevertheless, these difficulties may be overcome by protein isotope depletion. Thus, we aimed to use protein isotope depletion to analyze FPOP-oxidized samples by top-down MS analysis. For this purpose, we prepared isotopically natural (IN) and depleted (ID) forms of the FOXO4 DNA binding domain (FOXO4-DBD) and studied the protein-DNA interaction interface with double-stranded DNA, the insulin response element (IRE), after exposing the complex to hydroxyl radicals. As shown by comparing tandem mass spectra of natural and depleted proteins, the ID form increased the signal-to-noise ratio of useful fragment ions, thereby enhancing the sequence coverage by more than 19%. This improvement in the detection of fragment ions enabled us to detect 22 more oxidized residues in the ID samples than in the IN sample. Moreover, less common modifications were detected in the ID sample, including the formation of ketones and lysine carbonylation. Given the higher quality of ID top-down MSMS data set, these results provide more detailed information on the complex formation between transcription factors and DNA-response elements. Therefore, our study highlights the benefits of isotopic depletion for quantitative top-down proteomics. Data are available via ProteomeXchange with the identifier PXD044447.
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Affiliation(s)
- Marek Polák
- Institute
of Microbiology of the Czech Academy of Sciences, 14220 Prague, Czech Republic
- Department
of Biochemistry, Faculty of Science, Charles
University, 12843 Prague, Czech Republic
| | - Jiří Černý
- Laboratory
of Structural Bioinformatics of Proteins, Institute of Biotechnology of the Czech Academy of Sciences, 14220 Prague, Czech Republic
| | - Petr Novák
- Institute
of Microbiology of the Czech Academy of Sciences, 14220 Prague, Czech Republic
- Department
of Biochemistry, Faculty of Science, Charles
University, 12843 Prague, Czech Republic
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2
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Guo C, Cheng M, Li W, Gross ML. Precursor Reagent Hydrophobicity Affects Membrane Protein Footprinting. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2023; 34:2700-2710. [PMID: 37967285 PMCID: PMC10924779 DOI: 10.1021/jasms.3c00272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2023]
Abstract
Membrane proteins (MPs) play a crucial role in cell signaling, molecular transport, and catalysis and thus are at the heart of designing pharmacological targets. Although structural characterization of MPs at the molecular level is essential to elucidate their biological function, it poses a significant challenge for structural biology. Although mass spectrometry-based protein footprinting may be developed into a powerful approach for studying MPs, the hydrophobic character of membrane regions makes structural characterization difficult using water-soluble footprinting reagents. Herein, we evaluated a small series of MS-based photoactivated iodine reagents with different hydrophobicities. We used tip sonication to facilitate diffusion into micelles, thus enhancing reagent access to the hydrophobic core of MPs. Quantification of the modification extent in hydrophilic extracellular and hydrophobic transmembrane domains provides structurally sensitive information at the residue-level as measured by proteolysis and LC-MS/MS for a model MP, vitamin K epoxide reductase (VKOR). It also reveals a relationship between the reagent hydrophobicity and its preferential labeling sites in the local environment. The outcome should guide the future development of chemical probes for MPs and promote a direction for relatively high-throughput information-rich characterization of MPs in biochemistry and drug discovery.
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3
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Chen R, Song Y, Wang Z, Ji H, Du Z, Ma Q, Yang Y, Liu X, Li N, Sun Y. Developments in small-angle X-ray scattering (SAXS) for characterizing the structure of surfactant-macromolecule interactions and their complex. Int J Biol Macromol 2023; 251:126288. [PMID: 37582436 DOI: 10.1016/j.ijbiomac.2023.126288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 08/08/2023] [Accepted: 08/09/2023] [Indexed: 08/17/2023]
Abstract
The surfactant-macromolecule interactions (SMI) are one of the most critical topics for scientific research and industrial application. Small-angle X-ray scattering (SAXS) is a powerful tool for comprehensively studying the structural and conformational features of macromolecules at a size ranging from Angstroms to hundreds of nanometers with a time-resolve in milliseconds scale. The SAXS integrative techniques have emerged for comprehensively analyzing the SMI and the structure of their complex in solution. Here, the various types of emerging interactions of surfactant with macromolecules, such as protein, lipid, nuclear acid, polysaccharide and virus, etc. have been systematically reviewed. Additionally, the principle of SAXS and theoretical models of SAXS for describing the structure of SMI as well as their complex has been summarized. Moreover, the recent developments in the applications of SAXS for charactering the structure of SMI have been also highlighted. Prospectively, the capacity to complement artificial intelligence (AI) in the structure prediction of biological macromolecules and the high-throughput bioinformatics sequencing data make SAXS integrative structural techniques expected to be the primary methodology for illuminating the self-assembling dynamics and nanoscale structure of SMI. As advances in the field continue, we look forward to proliferating uses of SAXS based upon its abilities to robustly produce mechanistic insights for biology and medicine.
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Affiliation(s)
- Ruixin Chen
- College of Vocational and Technical Education, Yunnan Normal University, Kunming, Yunnan, China
| | - Yang Song
- College of Vocational and Technical Education, Yunnan Normal University, Kunming, Yunnan, China
| | - Zhichun Wang
- College of Vocational and Technical Education, Yunnan Normal University, Kunming, Yunnan, China
| | - Hang Ji
- College of Vocational and Technical Education, Yunnan Normal University, Kunming, Yunnan, China
| | - Zhongyao Du
- College of Vocational and Technical Education, Yunnan Normal University, Kunming, Yunnan, China
| | - Qingwen Ma
- College of Vocational and Technical Education, Yunnan Normal University, Kunming, Yunnan, China
| | - Ying Yang
- College of Vocational and Technical Education, Yunnan Normal University, Kunming, Yunnan, China
| | - Xingxun Liu
- College of Food Science and Engineering, Nanjing University of Finance and Economics, Nanjing, Jiangsu, China
| | - Na Li
- National Facility for Protein Science in Shanghai, Shanghai Advanced Research Institute, CAS, Shanghai, China.
| | - Yang Sun
- College of Vocational and Technical Education, Yunnan Normal University, Kunming, Yunnan, China.
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4
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Cornwell O, Ault JR. Fast photochemical oxidation of proteins coupled with mass spectrometry. BIOCHIMICA ET BIOPHYSICA ACTA. PROTEINS AND PROTEOMICS 2022; 1870:140829. [PMID: 35933084 DOI: 10.1016/j.bbapap.2022.140829] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 07/17/2022] [Accepted: 07/29/2022] [Indexed: 06/15/2023]
Abstract
Fast photochemical oxidation of proteins (FPOP) is a hydroxyl radical footprinting approach whereby radicals, produced by UV laser photolysis of hydrogen peroxide, induce oxidation of amino acid side-chains. Mass Spectrometry (MS) is employed to locate and quantify the resulting irreversible, covalent oxidations to use as a surrogate for side-chain solvent accessibility. Modulation of oxidation levels under different conditions allows for the characterisation of protein conformation, dynamics and binding epitopes. FPOP has been applied to structurally diverse and biopharmaceutically relevant systems from small, monomeric aggregation-prone proteins to proteome-wide analysis of whole organisms. This review evaluates the current state of FPOP, the progress needed to address data analysis bottlenecks, particularly for residue-level analysis, and highlights significant developments of the FPOP platform that have enabled its versatility and complementarity to other structural biology techniques.
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Affiliation(s)
- Owen Cornwell
- Waters Corporation, Stamford Avenue, Altrincham Road, Wilmslow SK9 4AX, UK
| | - James R Ault
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK.
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5
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Dafun AS, Marcoux J. Structural mass spectrometry of membrane proteins. BIOCHIMICA ET BIOPHYSICA ACTA. PROTEINS AND PROTEOMICS 2022; 1870:140813. [PMID: 35750312 DOI: 10.1016/j.bbapap.2022.140813] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 06/10/2022] [Accepted: 06/17/2022] [Indexed: 06/15/2023]
Abstract
The analysis of proteins and protein complexes by mass spectrometry (MS) has come a long way since the invention of electrospray ionization (ESI) in the mid 80s. Originally used to characterize small soluble polypeptide chains, MS has progressively evolved over the past 3 decades towards the analysis of samples of ever increasing heterogeneity and complexity, while the instruments have become more and more sensitive and resolutive. The proofs of concepts and first examples of most structural MS methods appeared in the early 90s. However, their application to membrane proteins, key targets in the biopharma industry, is more recent. Nowadays, a wealth of information can be gathered from such MS-based methods, on all aspects of membrane protein structure: sequencing (and more precisely proteoform characterization), but also stoichiometry, non-covalent ligand binding (metals, drug, lipids, carbohydrates), conformations, dynamics and distance restraints for modelling. In this review, we present the concept and some historical and more recent applications on membrane proteins, for the major structural MS methods.
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Affiliation(s)
- Angelique Sanchez Dafun
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Julien Marcoux
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, UPS, Toulouse, France.
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6
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Shen Q, Xiong T, Zheng W, Luo Y, Peng W, Dai J, Song R, Li Y, Liu S, Li B, Chen Y. The Effects of Thermal Treatment on Emulsifying Properties of Soy Protein Isolates: Interfacial Rheology and Quantitative Proteomic Analysis. Food Res Int 2022; 157:111326. [DOI: 10.1016/j.foodres.2022.111326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 04/26/2022] [Accepted: 04/28/2022] [Indexed: 11/17/2022]
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7
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Vallejo DD, Ramírez CR, Parson KF, Han Y, Gadkari VG, Ruotolo BT. Mass Spectrometry Methods for Measuring Protein Stability. Chem Rev 2022; 122:7690-7719. [PMID: 35316030 PMCID: PMC9197173 DOI: 10.1021/acs.chemrev.1c00857] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Mass spectrometry is a central technology in the life sciences, providing our most comprehensive account of the molecular inventory of the cell. In parallel with developments in mass spectrometry technologies targeting such assessments of cellular composition, mass spectrometry tools have emerged as versatile probes of biomolecular stability. In this review, we cover recent advancements in this branch of mass spectrometry that target proteins, a centrally important class of macromolecules that accounts for most biochemical functions and drug targets. Our efforts cover tools such as hydrogen-deuterium exchange, chemical cross-linking, ion mobility, collision induced unfolding, and other techniques capable of stability assessments on a proteomic scale. In addition, we focus on a range of application areas where mass spectrometry-driven protein stability measurements have made notable impacts, including studies of membrane proteins, heat shock proteins, amyloidogenic proteins, and biotherapeutics. We conclude by briefly discussing the future of this vibrant and fast-moving area of research.
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Affiliation(s)
- Daniel D. Vallejo
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Carolina Rojas Ramírez
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Kristine F. Parson
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Yilin Han
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Varun G. Gadkari
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Brandon T. Ruotolo
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
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8
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Sun J, Li W, Gross ML. Advances in mass spectrometry-based footprinting of membrane proteins. Proteomics 2022; 22:e2100222. [PMID: 35290716 PMCID: PMC10493193 DOI: 10.1002/pmic.202100222] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 02/24/2022] [Accepted: 02/25/2022] [Indexed: 11/09/2022]
Abstract
Structural biology is entering an exciting time where many new high-resolution structures of large complexes and membrane proteins (MPs) are determined regularly. These advances have been driven by over 15 years of technological improvements, first in macromolecular crystallography, and recently in cryo-electron microscopy. Obtaining information about MP higher order structure and interactions is also a frontier, important but challenging owing to their unique properties and the need to choose suitable detergents/lipids for their study. The development of mass spectrometry (MS), both instruments and methodology in the past 10 years, has also advanced it as a complementary method to study MP structure and interactions. In this review, we discuss advances in MS-based footprinting for MPs and highlight recent methodologies that offer new promise for MP study by chemical footprinting and mass spectrometry.
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Affiliation(s)
- Jie Sun
- Department of Chemistry, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Weikai Li
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Michael L Gross
- Department of Chemistry, Washington University in St. Louis, St. Louis, Missouri, USA
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9
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Polák M, Yassaghi G, Kavan D, Filandr F, Fiala J, Kukačka Z, Halada P, Loginov DS, Novák P. Utilization of Fast Photochemical Oxidation of Proteins and Both Bottom-up and Top-down Mass Spectrometry for Structural Characterization of a Transcription Factor-dsDNA Complex. Anal Chem 2022; 94:3203-3210. [PMID: 35134296 DOI: 10.1021/acs.analchem.1c04746] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
A combination of covalent labeling techniques and mass spectrometry (MS) is currently a progressive approach for deriving insights related to the mapping of protein surfaces or protein-ligand interactions. In this study, we mapped an interaction interface between the DNA binding domain (DBD) of FOXO4 protein and the DNA binding element (DAF16) using fast photochemical oxidation of proteins (FPOP). Residues involved in protein-DNA interaction were identified using the bottom-up approach. To confirm the findings and avoid a misinterpretation of the obtained data, caused by possible multiple radical oxidations leading to the protein surface alteration and oxidation of deeply buried amino acid residues, a top-down approach was employed for the first time in FPOP analysis. An isolation of singly oxidized ions enabled their gas-phase separation from multiply oxidized species followed by CID and ECD fragmentation. Application of both fragmentation techniques allowed generation of complementary fragment sets, out of which the regions shielded in the presence of DNA were deduced. The findings obtained by bottom-up and top-down approaches were highly consistent. Finally, FPOP results were compared with those of the HDX study of the FOXO4-DBD·DAF16 complex. No contradictions were found between the methods. Moreover, their combination provides complementary information related to the structure and dynamics of the protein-DNA complex. Data are available via ProteomeXchange with identifier PXD027624.
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Affiliation(s)
- Marek Polák
- Institute of Microbiology, The Czech Academy of Sciences, Prague, 14220, Czech Republic.,Faculty of Science, Charles University, Prague, 12843, Czech Republic
| | - Ghazaleh Yassaghi
- Institute of Microbiology, The Czech Academy of Sciences, Prague, 14220, Czech Republic
| | - Daniel Kavan
- Institute of Microbiology, The Czech Academy of Sciences, Prague, 14220, Czech Republic.,Faculty of Science, Charles University, Prague, 12843, Czech Republic
| | - František Filandr
- Institute of Microbiology, The Czech Academy of Sciences, Prague, 14220, Czech Republic.,Faculty of Science, Charles University, Prague, 12843, Czech Republic
| | - Jan Fiala
- Institute of Microbiology, The Czech Academy of Sciences, Prague, 14220, Czech Republic.,Faculty of Science, Charles University, Prague, 12843, Czech Republic
| | - Zdeněk Kukačka
- Institute of Microbiology, The Czech Academy of Sciences, Prague, 14220, Czech Republic
| | - Petr Halada
- Institute of Microbiology, The Czech Academy of Sciences, Prague, 14220, Czech Republic
| | - Dmitry S Loginov
- Institute of Microbiology, The Czech Academy of Sciences, Prague, 14220, Czech Republic.,Orekhovich Institute of Biomedical Chemistry, Moscow, 119191, Russia
| | - Petr Novák
- Institute of Microbiology, The Czech Academy of Sciences, Prague, 14220, Czech Republic
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10
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Pan X, Vachet RW. MEMBRANE PROTEIN STRUCTURES AND INTERACTIONS FROM COVALENT LABELING COUPLED WITH MASS SPECTROMETRY. MASS SPECTROMETRY REVIEWS 2022; 41:51-69. [PMID: 33145813 PMCID: PMC8093322 DOI: 10.1002/mas.21667] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 10/15/2020] [Accepted: 10/16/2020] [Indexed: 05/31/2023]
Abstract
Membrane proteins are incredibly important biomolecules because they mediate interactions between a cell's external and internal environment. Obtaining information about membrane protein structure and interactions is thus important for understanding these essential biomolecules. Compared with the analyses of water-soluble proteins, the structural analysis of membrane proteins is more challenging owing to their unique chemical properties and the presence of lipid components that are necessary to solubilize them. The combination of covalent labeling (CL) and mass spectrometry (MS) has recently been applied with great success to study membrane protein structure and interactions. These studies have demonstrated the many advantages that CL-MS methods have over other traditional biophysical techniques. In this review, we discuss both amino acid-specific and non-specific labeling approaches and the special considerations needed to address the unique challenges associated with interrogating membrane proteins. This review highlights the aspects of this approach that require special care to be applied correctly and provides a comprehensive review of the membrane protein systems that have been studied by CL-MS. © 2020 John Wiley & Sons Ltd. Mass Spec Rev.
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11
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Guo C, Cheng M, Li W, Gross ML. Diethylpyrocarbonate Footprints a Membrane Protein in Micelles. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2021; 32:2636-2643. [PMID: 34664961 PMCID: PMC8903028 DOI: 10.1021/jasms.1c00172] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Membrane proteins play crucial roles in cell signaling and transport and, thus, are the targets of many small molecule drugs. The characterization of membrane protein structures poses challenges for the high-resolution biophysical tools because the transmembrane (TM) domain is hydrophobic, opening an opportunity for mass spectrometry (MS)-based footprinting. The hydrophobic reagent diethylpyrocarbonate (DEPC), a heavily studied footprinter for water-soluble proteins, can label up to 30% of surface residues via a straightforward protocol, streamlining the MS-based footprinting workflow. To test its applicability to membrane proteins, we footprinted vitamin K epoxide reductase (VKOR) membrane protein with DEPC. The results demonstrate that besides labeling the hydrophilic extracellular (extramembrane (EM)) domain, DEPC can also diffuse into the hydrophobic TM domain and subsequently label that region. The labeling process was facilitated by tip sonication to enhance reagent diffusion into micelles. We then analyzed the correlation between the residue modification extent and the theoretical accessible surface area percentage (%ASA); the data generally show good correlation with the residue location. Compared with conventional hydrophilic footprinters, the relatively hydrophobic DEPC can map a membrane protein's TM domain, suggesting that the reagent's hydrophobicity can be exploited to obtain structural information on the membrane-spanning region. This encouraging result should assist in the development of more efficient footprinters for membrane protein TM domain footprinting, enabled by further understanding the relationship between a reagent's hydrophobicity and its preferred labeling sites.
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Affiliation(s)
- Chunyang Guo
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, United States
| | - Ming Cheng
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, United States
| | - Weikai Li
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - Michael L Gross
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, United States
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12
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Zhou F, Yang Y, Chemuru S, Cui W, Liu S, Gross M, Li W. Footprinting Mass Spectrometry of Membrane Proteins: Ferroportin Reconstituted in Saposin A Picodiscs. Anal Chem 2021; 93:11370-11378. [PMID: 34383472 DOI: 10.1021/acs.analchem.1c02325] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Membrane proteins participate in a broad range of cellular processes and represent more than 60% of drug targets. One approach to their structural analyses is mass spectrometry (MS)-based footprinting including hydrogen/deuterium exchange (HDX), fast photochemical oxidation of proteins (FPOP), and residue-specific chemical modification. Studying membrane proteins usually requires their isolation from the native lipid environment, after which they often become unstable. To overcome this problem, we are pursuing a novel methodology of incorporating membrane proteins into saposin A picodiscs for MS footprinting. We apply different footprinting approaches to a model membrane protein, mouse ferroportin, in picodiscs and achieve high coverage that enables the analysis of the ferroportin structure. FPOP footprinting shows extensive labeling of the extramembrane regions of ferroportin and protection at its transmembrane regions, suggesting that the membrane folding of ferroportin is maintained throughout the labeling process. In contrast, an amphipathic reagent, N-ethylmaleimide (NEM), efficiently labels cysteine residues in both extramembrane and transmembrane regions, thereby affording complementary footprinting coverage. Finally, optimization of sample treatment gives a peptic-map of ferroportin in picodiscs with 92% sequence coverage, setting the stage for HDX. These results, taken together, show that picodiscs are a new platform broadly applicable to mass spectrometry studies of membrane proteins.
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Affiliation(s)
- Fengbo Zhou
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - Yihu Yang
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - Saketh Chemuru
- Department of Chemistry, Washington University, St. Louis, Missouri 63110, United States
| | - Weidong Cui
- Department of Chemistry, Washington University, St. Louis, Missouri 63110, United States
| | - Shixuan Liu
- Department of Chemistry, Washington University, St. Louis, Missouri 63110, United States
| | - Michael Gross
- Department of Chemistry, Washington University, St. Louis, Missouri 63110, United States
| | - Weikai Li
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri 63110, United States
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13
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Cornwell O, Ault JR, Bond NJ, Radford SE, Ashcroft AE. Investigation of D76N β 2-Microglobulin Using Protein Footprinting and Structural Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2021; 32:1583-1592. [PMID: 33586970 PMCID: PMC9282677 DOI: 10.1021/jasms.0c00438] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
NMR studies and X-ray crystallography have shown that the structures of the 99-residue amyloidogenic protein β2-microglobulin (β2m) and its more aggregation-prone variant, D76N, are indistinguishable, and hence, the reason for the striking difference in their aggregation propensities remains elusive. Here, we have employed two protein footprinting methods, hydrogen-deuterium exchange (HDX) and fast photochemical oxidation of proteins (FPOP), in conjunction with ion mobility-mass spectrometry, to probe the differences in conformational dynamics of the two proteins. Using HDX-MS, a clear difference in HDX protection is observed between these two proteins in the E-F loop (residues 70-77) which contains the D76N substitution, with a significantly higher deuterium uptake being observed in the variant protein. Conversely, following FPOP-MS only minimal differences in the level of oxidation between the two proteins are observed in the E-F loop region, suggesting only modest side-chain movements in that area. Together the HDX-MS and FPOP-MS data suggest that a tangible perturbation to the hydrogen-bonding network in the E-F loop has taken place in the D76N variant and furthermore illustrate the benefit of using multiple complementary footprinting methods to address subtle, but possibly biologically important, differences between highly similar proteins.
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Affiliation(s)
- Owen Cornwell
- Biopharmaceuticals
R & D, AstraZeneca, Granta Park, Cambridge CB21 6GP, U.K.
| | - James R. Ault
- Astbury
Centre for Structural Molecular Biology & School of Molecular
and Cellular Biology, University of Leeds, Leeds LS2 9JT, U.K.
| | - Nicholas J. Bond
- Biopharmaceuticals
R & D, AstraZeneca, Granta Park, Cambridge CB21 6GP, U.K.
| | - Sheena E. Radford
- Astbury
Centre for Structural Molecular Biology & School of Molecular
and Cellular Biology, University of Leeds, Leeds LS2 9JT, U.K.
| | - Alison E. Ashcroft
- Astbury
Centre for Structural Molecular Biology & School of Molecular
and Cellular Biology, University of Leeds, Leeds LS2 9JT, U.K.
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14
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Cheng Z, Mobley C, Misra SK, Gadepalli RS, Hammond RI, Brown LS, Rimoldi JM, Sharp JS. Self-Organized Amphiphiles Are Poor Hydroxyl Radical Scavengers in Fast Photochemical Oxidation of Proteins Experiments. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2021; 32:1155-1161. [PMID: 33881849 PMCID: PMC8790760 DOI: 10.1021/jasms.0c00457] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Analysis of membrane protein topography using fast photochemical oxidation of proteins (FPOP) has been reported in recent years but is still underrepresented in literature. Based on the hydroxyl radical reactivity of lipids and other amphiphiles, it is believed that the membrane environment acts as a hydroxyl radical scavenger decreasing effective hydroxyl radical doses and resulting in less observed oxidation of proteins. We found no significant change in bulk solvent radical scavenging activity upon the addition of disrupted cellular membranes up to 25600 cells/μL using an inline radical dosimeter. We confirmed the nonscavenging nature of the membrane in bulk solution with the FPOP results of a soluble model protein in the presence of cell membranes, which showed no significant difference in oxidation with or without membranes. The use of detergents revealed that, while soluble detergent below the critical micelle concentration is a potent hydroxyl radical scavenger, additional detergent has little to no hydroxyl radical scavenging effect once the critical micelle concentration is reached. Examination of both an extracellular peptide of the integral membrane protein bacteriorhodopsin as well as a novel hydroxyl radical dosimeter tethered to a Triton X-series amphiphile indicate that proximity to the membrane surface greatly decreases reaction with hydroxyl radicals, even though the oxidation target is equally solvent accessible. These results suggest that the observed reduced oxidation of solvent-accessible surfaces of integral membrane proteins is due to the high local concentration of radical scavengers in the membrane or membrane mimetics competing for the local concentration of hydroxyl radicals.
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Affiliation(s)
- Zhi Cheng
- Department of Biomolecular Sciences, University of Mississippi, University, MS 38677
| | - Charles Mobley
- Department of Biomolecular Sciences, University of Mississippi, University, MS 38677
| | - Sandeep K. Misra
- Department of Biomolecular Sciences, University of Mississippi, University, MS 38677
| | - Rama S. Gadepalli
- Department of Biomolecular Sciences, University of Mississippi, University, MS 38677
| | - Rachel I. Hammond
- Department of Biomolecular Sciences, University of Mississippi, University, MS 38677
| | - Leonid S. Brown
- Department of Physics and Biophysics Interdepartmental Group, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - John M. Rimoldi
- Department of Biomolecular Sciences, University of Mississippi, University, MS 38677
| | - Joshua S. Sharp
- Department of Biomolecular Sciences, University of Mississippi, University, MS 38677
- Department of Chemistry and Biochemistry, University of Mississippi, University, MS 38677
- GenNext Technologies, Inc. Half Moon Bay, CA 94019
- Correspondence to
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15
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McKenzie-Coe A, Shortt R, Jones LM. THE MAKING OF A FOOTPRINT IN PROTEIN FOOTPRINTING: A REVIEW IN HONOR OF MICHAEL L. GROSS. MASS SPECTROMETRY REVIEWS 2021; 40:177-200. [PMID: 32400038 PMCID: PMC7849054 DOI: 10.1002/mas.21632] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 04/17/2020] [Accepted: 04/23/2020] [Indexed: 06/11/2023]
Abstract
Within the past decade protein footprinting in conjunction with mass spectrometry has become a powerful and versatile means to unravel the higher order structure of proteins. Footprinting-based approaches has demonstrated the capacity to inform on interaction sites and dynamic regions that participate in conformational changes. These findings when set in a biological perspective inform on protein folding/unfolding, protein-protein interactions, and protein-ligand interactions. In this review, we will look at the contribution of Dr. Michael L. Gross to protein footprinting approaches such as hydrogen deuterium exchange mass spectrometry and hydroxyl radical protein footprinting. This review details the development of novel footprinting methods as well as their applications to study higher order protein structure. © 2020 The Authors. Mass Spectrometry Reviews published by John Wiley & Sons Ltd. Mass Spec Rev.
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Affiliation(s)
- Alan McKenzie-Coe
- Department of Pharmaceutical Sciences, University of Maryland Baltimore, Baltimore, Maryland, 21201
| | - Raquel Shortt
- Department of Pharmaceutical Sciences, University of Maryland Baltimore, Baltimore, Maryland, 21201
| | - Lisa M Jones
- Department of Pharmaceutical Sciences, University of Maryland Baltimore, Baltimore, Maryland, 21201
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16
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Cheng M, Guo C, Li W, Gross ML. Free‐Radical Membrane Protein Footprinting by Photolysis of Perfluoroisopropyl Iodide Partitioned to Detergent Micelle by Sonication. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202014096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Ming Cheng
- Department of Chemistry Washington University in St. Louis One Brookings Drive Saint Louis MO 63130 USA
- Current address: Department of Molecular Medicine The Scripps Research Institute La Jolla CA 92037 USA
| | - Chunyang Guo
- Department of Chemistry Washington University in St. Louis One Brookings Drive Saint Louis MO 63130 USA
| | - Weikai Li
- Department of Biochemistry and Molecular Biophysics Washington University School of Medicine St. Louis MO 63130 USA
| | - Michael L. Gross
- Department of Chemistry Washington University in St. Louis One Brookings Drive Saint Louis MO 63130 USA
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17
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Cheng M, Guo C, Li W, Gross ML. Free-Radical Membrane Protein Footprinting by Photolysis of Perfluoroisopropyl Iodide Partitioned to Detergent Micelle by Sonication. Angew Chem Int Ed Engl 2021; 60:8867-8873. [PMID: 33751812 PMCID: PMC8083173 DOI: 10.1002/anie.202014096] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 12/29/2020] [Indexed: 12/14/2022]
Abstract
A free-radical footprinting approach is described for integral membrane protein (IMP) that extends, significantly, the "fast photochemical oxidation of proteins" (FPOP) platform. This new approach exploits highly hydrophobic perfluoroisopropyl iodide (PFIPI) together with tip sonication to ensure efficient transport into the micelle interior, allowing laser dissociation and footprinting of the transmembrane domains. In contrast to water soluble footprinters, PFIPI footprints both the hydrophobic intramembrane and the hydrophilic extramembrane domains of the IMP vitamin K epoxide reductase (VKOR). The footprinting is fast, giving high coverage for Tyr (100 %) and Trp. The incorporation of the reagent with sonication does not significantly affect VKOR's enzymatic function, and tyrosine iodination does not compromise protease digestion and the subsequent analysis. The locations for the modifications are largely consistent with the corresponding solvent accessibilities, recommending this approach for future membrane protein footprinting.
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Affiliation(s)
- Ming Cheng
- Department of Chemistry, Washington University in St. Louis, One Brookings Drive, Saint Louis, MO, 63130, USA
- Current address: Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Chunyang Guo
- Department of Chemistry, Washington University in St. Louis, One Brookings Drive, Saint Louis, MO, 63130, USA
| | - Weikai Li
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, 63130, USA
| | - Michael L Gross
- Department of Chemistry, Washington University in St. Louis, One Brookings Drive, Saint Louis, MO, 63130, USA
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18
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Hammerschmid D, van Dyck JF, Sobott F, Calabrese AN. Interrogating Membrane Protein Structure and Lipid Interactions by Native Mass Spectrometry. Methods Mol Biol 2021; 2168:233-261. [PMID: 33582995 DOI: 10.1007/978-1-0716-0724-4_11] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
Native mass spectrometry and native ion mobility mass spectrometry are now established techniques in structural biology, with recent work developing these methods for the study of integral membrane proteins reconstituted in both lipid bilayer and detergent environments. Here we show how native mass spectrometry can be used to interrogate integral membrane proteins, providing insights into conformation, oligomerization, subunit composition/stoichiometry, and interactions with detergents/lipids/drugs. Furthermore, we discuss the sample requirements and experimental considerations unique to integral membrane protein native mass spectrometry research.
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Affiliation(s)
- Dietmar Hammerschmid
- Protein Chemistry, Proteomics and Epigenetic Signalling (PPES), Department of Biomedical Sciences, University of Antwerp, Wilrijk, Belgium.,Biomolecular & Analytical Mass Spectrometry Group, Chemistry Department, University of Antwerp, Antwerp, Belgium
| | - Jeroen F van Dyck
- Biomolecular & Analytical Mass Spectrometry Group, Chemistry Department, University of Antwerp, Antwerp, Belgium
| | - Frank Sobott
- Biomolecular & Analytical Mass Spectrometry Group, Chemistry Department, University of Antwerp, Antwerp, Belgium.,Faculty of Biological Sciences, School of Molecular and Cellular Biology, University of Leeds, Leeds, UK.,Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
| | - Antonio N Calabrese
- Faculty of Biological Sciences, School of Molecular and Cellular Biology, University of Leeds, Leeds, UK. .,Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK.
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19
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Styrene maleic-acid lipid particles (SMALPs) into detergent or amphipols: An exchange protocol for membrane protein characterisation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183192. [PMID: 31945320 PMCID: PMC7086155 DOI: 10.1016/j.bbamem.2020.183192] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 12/06/2019] [Accepted: 01/10/2020] [Indexed: 12/24/2022]
Abstract
Membrane proteins are traditionally extracted and purified in detergent for biochemical and structural characterisation. This process is often costly and laborious, and the stripping away of potentially stabilising lipids from the membrane protein of interest can have detrimental effects on protein integrity. Recently, styrene-maleic acid (SMA) co-polymers have offered a solution to this problem by extracting membrane proteins directly from their native membrane, while retaining their naturally associated lipids in the form of stable SMA lipid particles (SMALPs). However, the inherent nature and heterogeneity of the polymer renders their use challenging for some downstream applications – particularly mass spectrometry (MS). While advances in cryo-electron microscopy (cryo-EM) have enhanced our understanding of membrane protein:lipid interactions in both SMALPs and detergent, the resolution obtained with this technique is often insufficient to accurately identify closely associated lipids within the transmembrane annulus. Native-MS has the power to fill this knowledge gap, but the SMA polymer itself remains largely incompatible with this technique. To increase sample homogeneity and allow characterisation of membrane protein:lipid complexes by native-MS, we have developed a novel SMA-exchange method; whereby the membrane protein of interest is first solubilised and purified in SMA, then transferred into amphipols or detergents. This allows the membrane protein and endogenously associated lipids extracted by SMA co-polymer to be identified and examined by MS, thereby complementing results obtained by cryo-EM and creating a better understanding of how the lipid bilayer directly affects membrane protein structure and function. First reported exchange protocol for transferring membrane proteins solubilised in SMALPs, into detergent or amphipols. Purification of protein:lipid complexes without detergent for mass spectrometry and subsequent lipid identification. Cost effective membrane protein purification requiring only minimal amounts of detergents in the exchange process.
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20
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Johnson DT, Di Stefano LH, Jones LM. Fast photochemical oxidation of proteins (FPOP): A powerful mass spectrometry-based structural proteomics tool. J Biol Chem 2019; 294:11969-11979. [PMID: 31262727 DOI: 10.1074/jbc.rev119.006218] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Fast photochemical oxidation of proteins (FPOP) is a MS-based method that has proved useful in studies of protein structures, interactions, conformations, and protein folding. The success of this method relies on the irreversible labeling of solvent-exposed amino acid side chains by hydroxyl radicals. FPOP generates these radicals through laser-induced photolysis of hydrogen peroxide. The data obtained provide residue-level resolution of protein structures and interactions on the microsecond timescale, enabling investigations of fast processes such as protein folding and weak protein-protein interactions. An extensive comparison between FPOP and other footprinting techniques gives insight on their complementarity as well as the robustness of FPOP to provide unique structural information once unattainable. The versatility of this method is evidenced by both the heterogeneity of samples that can be analyzed by FPOP and the myriad of applications for which the method has been successfully used: from proteins of varying size to intact cells. This review discusses the wide applications of this technique and highlights its high potential. Applications including, but not limited to, protein folding, membrane proteins, structure elucidation, and epitope mapping are showcased. Furthermore, the use of FPOP has been extended to probing proteins in cells and in vivo These promising developments are also presented herein.
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Affiliation(s)
- Danté T Johnson
- Department of Pharmaceutical Sciences, University of Maryland, Baltimore, Maryland 21201
| | - Luciano H Di Stefano
- Department of Pharmaceutical Sciences, University of Maryland, Baltimore, Maryland 21201
| | - Lisa M Jones
- Department of Pharmaceutical Sciences, University of Maryland, Baltimore, Maryland 21201.
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21
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Li Y, Lee JS. Staring at protein-surfactant interactions: Fundamental approaches and comparative evaluation of their combinations - A review. Anal Chim Acta 2019; 1063:18-39. [DOI: 10.1016/j.aca.2019.02.024] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2018] [Revised: 02/15/2019] [Accepted: 02/18/2019] [Indexed: 02/07/2023]
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22
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Shi L, Gross ML. Fast Photochemical Oxidation of Proteins Coupled with Mass Spectrometry. Protein Pept Lett 2019; 26:27-34. [PMID: 30484399 DOI: 10.2174/0929866526666181128124554] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 08/30/2018] [Accepted: 09/27/2018] [Indexed: 11/22/2022]
Abstract
BACKGROUND Determination of the composition and some structural features of macromolecules can be achieved by using structural proteomics approaches coupled with mass spectrometry (MS). One approach is hydroxyl radical protein footprinting whereby amino-acid side chains are modified with reactive reagents to modify irreversibly a protein side chain. The outcomes, when deciphered with mass-spectrometry-based proteomics, can increase our knowledge of structure, assembly, and conformational dynamics of macromolecules in solution. Generating the hydroxyl radicals by laser irradiation, Hambly and Gross developed the approach of Fast Photochemical Oxidation of Proteins (FPOP), which labels proteins on the sub millisecond time scale and provides, with MS analysis, deeper understanding of protein structure and protein-ligand and protein- protein interactions. This review highlights the fundamentals of FPOP and provides descriptions of hydroxyl-radical and other radical and carbene generation, of the hydroxyl labeling of proteins, and of determination of protein modification sites. We also summarize some recent applications of FPOP coupled with MS in protein footprinting. CONCLUSION We survey results that show the capability of FPOP for qualitatively measuring protein solvent accessibility on the residue level. To make these approaches more valuable, we describe recent method developments that increase FPOP's quantitative capacity and increase the spatial protein sequence coverage. To improve FPOP further, several new labeling reagents including carbenes and other radicals have been developed. These growing improvements will allow oxidative- footprinting methods coupled with MS to play an increasingly significant role in determining the structure and dynamics of macromolecules and their assemblies.
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Affiliation(s)
- Liuqing Shi
- Department of Chemistry, Washington University, St. Louis, MO 63130, United States
| | - Michael L Gross
- Department of Chemistry, Washington University, St. Louis, MO 63130, United States
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23
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Cornwell O, Radford SE, Ashcroft AE, Ault JR. Comparing Hydrogen Deuterium Exchange and Fast Photochemical Oxidation of Proteins: a Structural Characterisation of Wild-Type and ΔN6 β 2-Microglobulin. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2018; 29:2413-2426. [PMID: 30267362 PMCID: PMC6276068 DOI: 10.1007/s13361-018-2067-y] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 09/07/2018] [Accepted: 09/10/2018] [Indexed: 05/23/2023]
Abstract
Hydrogen deuterium exchange (HDX) coupled to mass spectrometry (MS) is a well-established technique employed in the field of structural MS to probe the solvent accessibility, dynamics and hydrogen bonding of backbone amides in proteins. By contrast, fast photochemical oxidation of proteins (FPOP) uses hydroxyl radicals, liberated from the photolysis of hydrogen peroxide, to covalently label solvent accessible amino acid side chains on the microsecond-millisecond timescale. Here, we use these two techniques to study the structural and dynamical differences between the protein β2-microglobulin (β2m) and its amyloidogenic truncation variant, ΔN6. We show that HDX and FPOP highlight structural/dynamical differences in regions of the proteins, localised to the region surrounding the N-terminal truncation. Further, we demonstrate that, with carefully optimised LC-MS conditions, FPOP data can probe solvent accessibility at the sub-amino acid level, and that these data can be interpreted meaningfully to gain more detailed understanding of the local environment and orientation of the side chains in protein structures. Graphical Abstract ᅟ.
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Affiliation(s)
- Owen Cornwell
- 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
| | - Alison E Ashcroft
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK.
| | - James R Ault
- 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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24
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Riaz M, Misra SK, Sharp JS. Towards high-throughput fast photochemical oxidation of proteins: Quantifying exposure in high fluence microtiter plate photolysis. Anal Biochem 2018; 561-562:32-36. [PMID: 30240591 PMCID: PMC6186496 DOI: 10.1016/j.ab.2018.09.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 09/06/2018] [Accepted: 09/17/2018] [Indexed: 01/15/2023]
Abstract
Protein structural analysis by mass spectrometry has gained significant popularity in recent years, including high-resolution protein topographical mapping by fast photochemical oxidation of proteins (FPOP). The ability to provide protein topographical information at moderate spatial resolution makes FPOP an attractive technology for the protein pharmaceutical discovery and development processes. However, current technology limits the throughput and requires significant manual sample manipulation. Similarly, as FPOP is being used on larger samples, sample flow through the capillary becomes challenging. No systematic comparison of the performance of static flash photolysis with traditional flow FPOP has been reported. Here, we evaluate a 96-well microtiter-based laser flash photolysis method for the topographical probing of proteins, which subsequently could be used to analyze higher order structure of the protein in a high-throughput fashion with minimal manual sample manipulation. We used multiple metrics to compare microtiter FPOP performance with that of traditional flow FPOP: adenine-based hydroxyl radical dosimetry, oxidation efficiency of a model peptide, and hydroxyl radical protein footprint of myoglobin. In all cases, microtiter plate FPOP performed comparably with traditional flow FPOP, requiring a small fraction of the time for exposure. This greatly reduced sample exposure time, coupled with automated sample handling in 96-well microtiter plates, makes microtiter-based FPOP an important step in achieving the throughput required to adapt hydroxyl radical protein footprinting for screening purposes.
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Affiliation(s)
- Mohammad Riaz
- Department of BioMolecular Sciences, University of Mississippi, University, MS, 38677, USA
| | - Sandeep K Misra
- Department of BioMolecular Sciences, University of Mississippi, University, MS, 38677, USA
| | - Joshua S Sharp
- Department of BioMolecular Sciences, University of Mississippi, University, MS, 38677, USA.
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25
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Calabrese AN, Radford SE. Mass spectrometry-enabled structural biology of membrane proteins. Methods 2018; 147:187-205. [DOI: 10.1016/j.ymeth.2018.02.020] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Revised: 01/30/2018] [Accepted: 02/21/2018] [Indexed: 01/01/2023] Open
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26
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Limpikirati P, Liu T, Vachet RW. Covalent labeling-mass spectrometry with non-specific reagents for studying protein structure and interactions. Methods 2018; 144:79-93. [PMID: 29630925 PMCID: PMC6051898 DOI: 10.1016/j.ymeth.2018.04.002] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Revised: 04/03/2018] [Accepted: 04/04/2018] [Indexed: 12/13/2022] Open
Abstract
Using mass spectrometry (MS) to obtain information about a higher order structure of protein requires that a protein's structural properties are encoded into the mass of that protein. Covalent labeling (CL) with reagents that can irreversibly modify solvent accessible amino acid side chains is an effective way to encode structural information into the mass of a protein, as this information can be read-out in a straightforward manner using standard MS-based proteomics techniques. The differential reactivity of proteins under two or more conditions can be used to distinguish protein topologies, conformations, and/or binding sites. CL-MS methods have been effectively used for the structural analysis of proteins and protein complexes, particularly for systems that are difficult to study by other more traditional biochemical techniques. This review provides an overview of the non-specific CL approaches that have been combined with MS with a particular emphasis on the reagents that are commonly used, including hydroxyl radicals, carbenes, and diethylpyrocarbonate. We describe the reagent and protein factors that affect the reactivity of amino acid side chains. We also include details about experimental design and workflow, data analysis, recent applications, and some future prospects of CL-MS methods.
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Affiliation(s)
| | - Tianying Liu
- Department of Chemistry, University of Massachusetts Amherst, MA 01003, United States
| | - Richard W Vachet
- Department of Chemistry, University of Massachusetts Amherst, MA 01003, United States.
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27
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Implementing fast photochemical oxidation of proteins (FPOP) as a footprinting approach to solve diverse problems in structural biology. Methods 2018; 144:94-103. [PMID: 29800613 DOI: 10.1016/j.ymeth.2018.05.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 05/18/2018] [Accepted: 05/19/2018] [Indexed: 11/24/2022] Open
Abstract
Fast photochemical oxidation of proteins (FPOP) is a footprinting technique used in mass spectrometry-based structural proteomics. It has been applied to solve a variety of problems in different areas of biology. A FPOP platform requires a laser, optics, and sample flow path properly assembled to enable fast footprinting. Sample preparation, buffer conditions, and reagent concentrations are essential to obtain reasonable oxidations on proteins. FPOP samples can be analyzed by LC-MS methods to measure the modification extent, which is a function of the solvent-accessible surface area of the protein. The platform can be expanded to accommodate several new approaches, including dose-response studies, new footprinting reagents, and two-laser pump-probe experiments. Here, we briefly review FPOP applications and in a detailed manner describe the procedures to set up an FPOP protein footprinting platform.
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28
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Rathore D, Faustino A, Schiel J, Pang E, Boyne M, Rogstad S. The role of mass spectrometry in the characterization of biologic protein products. Expert Rev Proteomics 2018; 15:431-449. [DOI: 10.1080/14789450.2018.1469982] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Deepali Rathore
- Division of Pharmaceutical Analysis, Office of Testing and Research, Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD, USA
- Center for Biomedical Mass Spectrometry Research, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Anneliese Faustino
- Division of Pharmaceutical Analysis, Office of Testing and Research, Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD, USA
| | - John Schiel
- Biomolecular Measurement Division, National Institute of Standards and Technology, Institute for Bioscience and Biotechnology Research, Rockville, MD, USA
| | - Eric Pang
- Office of Lifecycle Drug Products, Office of Pharmaceutical Quality, Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD, USA
| | - Michael Boyne
- Division of Pharmaceutical Analysis, Office of Testing and Research, Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD, USA
- COUR Pharmaceuticals Development Company, Northbrook, IL, USA
| | - Sarah Rogstad
- Division of Pharmaceutical Analysis, Office of Testing and Research, Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD, USA
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