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Kuwajima K, Yagi-Utsumi M, Yanaka S, Kato K. DMSO-Quenched H/D-Exchange 2D NMR Spectroscopy and Its Applications in Protein Science. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27123748. [PMID: 35744871 PMCID: PMC9230524 DOI: 10.3390/molecules27123748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 06/06/2022] [Accepted: 06/07/2022] [Indexed: 11/16/2022]
Abstract
Hydrogen/deuterium (H/D) exchange combined with two-dimensional (2D) NMR spectroscopy has been widely used for studying the structure, stability, and dynamics of proteins. When we apply the H/D-exchange method to investigate non-native states of proteins such as equilibrium and kinetic folding intermediates, H/D-exchange quenching techniques are indispensable, because the exchange reaction is usually too fast to follow by 2D NMR. In this article, we will describe the dimethylsulfoxide (DMSO)-quenched H/D-exchange method and its applications in protein science. In this method, the H/D-exchange buffer is replaced by an aprotic DMSO solution, which quenches the exchange reaction. We have improved the DMSO-quenched method by using spin desalting columns, which are used for medium exchange from the H/D-exchange buffer to the DMSO solution. This improvement has allowed us to monitor the H/D exchange of proteins at a high concentration of salts or denaturants. We describe methodological details of the improved DMSO-quenched method and present a case study using the improved method on the H/D-exchange behavior of unfolded human ubiquitin in 6 M guanidinium chloride.
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Affiliation(s)
- Kunihiro Kuwajima
- Department of Physics, School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
- Correspondence: (K.K.); (K.K.)
| | - Maho Yagi-Utsumi
- Exploratory Research Center on Life and Living Systems and Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Aichi, Japan; (M.Y.-U.); (S.Y.)
- Department of Functional Molecular Science, School of Physical Sciences, SOKENDAI (the Graduate University for Advanced Studies), 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Aichi, Japan
- Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya 467-8603, Aichi, Japan
| | - Saeko Yanaka
- Exploratory Research Center on Life and Living Systems and Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Aichi, Japan; (M.Y.-U.); (S.Y.)
- Department of Functional Molecular Science, School of Physical Sciences, SOKENDAI (the Graduate University for Advanced Studies), 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Aichi, Japan
| | - Koichi Kato
- Exploratory Research Center on Life and Living Systems and Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Aichi, Japan; (M.Y.-U.); (S.Y.)
- Department of Functional Molecular Science, School of Physical Sciences, SOKENDAI (the Graduate University for Advanced Studies), 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Aichi, Japan
- Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya 467-8603, Aichi, Japan
- Correspondence: (K.K.); (K.K.)
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2
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Sanches K, Wai DCC, Norton RS. Conformational dynamics in peptide toxins: Implications for receptor interactions and molecular design. Toxicon 2021; 201:127-140. [PMID: 34454969 DOI: 10.1016/j.toxicon.2021.08.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 08/19/2021] [Accepted: 08/23/2021] [Indexed: 10/20/2022]
Abstract
Peptide toxins are potent and often exquisitely selective probes of the structure and function of ion channels and receptors, and are therefore of significant interest to the pharmaceutical and biotech industries as both pharmacological tools and therapeutic leads. The three-dimensional structures of peptide toxins are essential as a basis for understanding their structure-activity relationships and their binding to target receptors, as well as in guiding the design of analogues with modified potency and/or selectivity for key targets. NMR spectroscopy has played a key role in elucidating the structures of peptide toxins and probing their structure-function relationships. In this article, we highlight the additional important contribution of NMR to characterising the dynamics of peptide toxins. We also compare the information available from NMR measurements with that afforded by molecular dynamics simulations. We describe several examples of the importance of dynamics measurements over a range of timescales for understanding the structure-function relationships of peptide toxins and their receptor engagement. Peptide toxins that inhibit the voltage-gated potassium channel KV1.3 with pM affinities display different degrees of conformational flexibility, even though they contain multiple disulfide bonds, and this flexibility can affect the relative orientation of residues that have been shown to be critical for channel binding. Information on the dynamic properties of peptide toxins is important in the design of analogues or mimetics where receptor-bound structures are not available.
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Affiliation(s)
- Karoline Sanches
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, 3052, Australia; ARC Centre for Fragment-Based Design, Monash University, Parkville, Victoria, 3052, Australia
| | - Dorothy C C Wai
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, 3052, Australia
| | - Raymond S Norton
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, 3052, Australia; ARC Centre for Fragment-Based Design, Monash University, Parkville, Victoria, 3052, Australia.
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3
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Zhang Y, Chen X, Zhang L, Shi Q, Zhao S, Xu C. Specification of the nitrogen functional group in a hydrotreated petroleum molecule using hydrogen/deuterium exchange electrospray ionization high-resolution mass spectrometry. Analyst 2020; 145:4442-4451. [PMID: 32529999 DOI: 10.1039/d0an00772b] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Hydrotreatment is extensively used for the production of clean fuel. Attaining an understanding of the structural conversion of the nitrogen species during hydrotreatment is very challenging due to the compositional complexity and the absence of a proper characterization method. In the presented work, we coupled hydrogen/deuterium exchange (HDX) with positive-ion electrospray ionization high-resolution mass spectrometry ((+) ESI HR MS) to investigate the difference between the composition of the nitrogen-containing species and the functional groups before and after hydrotreatment. The solvent and additive were optimized for HDX (+) ESI HRMS through systematic evaluations on model nitrogen-containing compounds. We found that adding deuterated water (D2O) and deuterated formic acid (DCOOD) significantly increased the degree of HDX and thus facilitated the identification of nitrogen functional groups. After application to the hydrotreated petroleum samples, the compositional variation of intermediate amine compounds during the heavy petroleum hydrotreatment process was clearly revealed.
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Affiliation(s)
- Ying Zhang
- State Key Laboratory of Heavy Oil Processing & Petroleum Molecular Engineering Center (PMEC), China University of Petroleum, Beijing 102249, China.
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4
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Liu XR, Zhang MM, Gross ML. Mass Spectrometry-Based Protein Footprinting for Higher-Order Structure Analysis: Fundamentals and Applications. Chem Rev 2020; 120:4355-4454. [PMID: 32319757 PMCID: PMC7531764 DOI: 10.1021/acs.chemrev.9b00815] [Citation(s) in RCA: 130] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Proteins adopt different higher-order structures (HOS) to enable their unique biological functions. Understanding the complexities of protein higher-order structures and dynamics requires integrated approaches, where mass spectrometry (MS) is now positioned to play a key role. One of those approaches is protein footprinting. Although the initial demonstration of footprinting was for the HOS determination of protein/nucleic acid binding, the concept was later adapted to MS-based protein HOS analysis, through which different covalent labeling approaches "mark" the solvent accessible surface area (SASA) of proteins to reflect protein HOS. Hydrogen-deuterium exchange (HDX), where deuterium in D2O replaces hydrogen of the backbone amides, is the most common example of footprinting. Its advantage is that the footprint reflects SASA and hydrogen bonding, whereas one drawback is the labeling is reversible. Another example of footprinting is slow irreversible labeling of functional groups on amino acid side chains by targeted reagents with high specificity, probing structural changes at selected sites. A third footprinting approach is by reactions with fast, irreversible labeling species that are highly reactive and footprint broadly several amino acid residue side chains on the time scale of submilliseconds. All of these covalent labeling approaches combine to constitute a problem-solving toolbox that enables mass spectrometry as a valuable tool for HOS elucidation. As there has been a growing need for MS-based protein footprinting in both academia and industry owing to its high throughput capability, prompt availability, and high spatial resolution, we present a summary of the history, descriptions, principles, mechanisms, and applications of these covalent labeling approaches. Moreover, their applications are highlighted according to the biological questions they can answer. This review is intended as a tutorial for MS-based protein HOS elucidation and as a reference for investigators seeking a MS-based tool to address structural questions in protein science.
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Affiliation(s)
| | | | - Michael L. Gross
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO, USA, 63130
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5
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Hwang S, Öster C, Chevelkov V, Giller K, Lange S, Becker S, Lange A. Characterization of H/D exchange in type 1 pili by proton-detected solid-state NMR and molecular dynamics simulations. JOURNAL OF BIOMOLECULAR NMR 2019; 73:281-291. [PMID: 31028572 PMCID: PMC6692446 DOI: 10.1007/s10858-019-00247-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 04/11/2019] [Indexed: 06/09/2023]
Abstract
Uropathogenic Escherichia coli invades and colonizes hosts by attaching to cells using adhesive pili on the bacterial surface. Although many biophysical techniques have been used to study the structure and mechanical properties of pili, many important details are still unknown. Here we use proton-detected solid-state NMR experiments to investigate solvent accessibility and structural dynamics. Deuterium back-exchange at labile sites of the perdeuterated, fully proton back-exchanged pili was conducted to investigate hydrogen/deuterium (H/D) exchange patterns of backbone amide protons in pre-assembled pili. We found distinct H/D exchange patterns in lateral and axial intermolecular interfaces in pili. Amide protons protected from H/D exchange in pili are mainly located in the core region of the monomeric subunit and in the lateral intermolecular interface, whereas the axial intermolecular interface and the exterior region of pili are highly exposed to H/D exchange. Additionally, we performed molecular dynamics simulations of the type 1 pilus rod and estimated the probability of H/D exchange based on hydrogen bond dynamics. The comparison of the experimental observables and simulation data provides insights into stability and mechanical properties of pili.
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Affiliation(s)
- Songhwan Hwang
- Department of Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
| | - Carl Öster
- Department of Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
| | - Veniamin Chevelkov
- Department of Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
| | - Karin Giller
- Department of NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Sascha Lange
- Department of Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
| | - Stefan Becker
- Department of NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Adam Lange
- Department of Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany.
- Institut für Biologie, Humboldt-Universität Zu Berlin, Berlin, Germany.
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6
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Mackenzie HW, Hansen DF. Arginine Side-Chain Hydrogen Exchange: Quantifying Arginine Side-Chain Interactions in Solution. Chemphyschem 2019; 20:252-259. [PMID: 30085401 PMCID: PMC6391956 DOI: 10.1002/cphc.201800598] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Indexed: 02/03/2023]
Abstract
The rate with which labile backbone hydrogen atoms in proteins exchange with the solvent has long been used to probe protein interactions in aqueous solutions. Arginine, an essential amino acid found in many interaction interfaces, is capable of an impressive range of interactions via its guanidinium group. The hydrogen exchange rate of the guanidinium hydrogens therefore becomes an important measure to quantify side-chain interactions. Herein we present an NMR method to quantify the hydrogen exchange rates of arginine side-chain 1 Hϵ protons and thus present a method to gauge the strength of arginine side-chain interactions. The method employs 13 C-detection and the one-bond deuterium isotope shift observed for 15 Nϵ to generate two exchanging species in 1 H2 O/2 H2 O mixtures. An application to the protein T4 Lysozyme is shown, where protection factors calculated from the obtained exchange rates correlate well with the interactions observed in the crystal structure. The methodology presented provides an important step towards characterising interactions of arginine side-chains in enzymes, in phase separation, and in protein interaction interfaces in general.
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Affiliation(s)
- Harold W. Mackenzie
- Institute of Structural and Molecular Biology Division of BiosciencesUniversity College LondonLondon WC1E 6BTUnited Kingdom
| | - D. Flemming Hansen
- Institute of Structural and Molecular Biology Division of BiosciencesUniversity College LondonLondon WC1E 6BTUnited Kingdom
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7
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Shigemitsu Y, Hiroaki H. Common molecular pathogenesis of disease-related intrinsically disordered proteins revealed by NMR analysis. J Biochem 2018; 163:11-18. [PMID: 28992347 DOI: 10.1093/jb/mvx056] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 06/17/2017] [Indexed: 01/23/2023] Open
Abstract
Intrinsically disordered proteins (IDPs) are either completely unstructured or contain large disordered regions in their native state; they have drawn much attention in the field of molecular pathology. Some of them substantially tend to form protein self-assemblies, such as toxic or non-toxic aggregates and fibrils, and have been postulated to relate to diseases. These disease-related IDPs include Aβ(1-42) [Alzheimer's disease (AD)], Tau (AD and tauopathy), α-synuclein (Parkinson's disease) and p53 (cancer). Several studies suggest that these aggregation and/or fibril formation processes are often initiated by transient conformational changes of the IDPs prior to protein self-assembly. Interestingly, the pathological molecular processes of these IDPs share multiple common features with those of protein misfolding diseases, such as transmissible spongiform encephalopathy (PrPsc) and AL-amyloidosis (VL-domain of γ-immunoglobulin). This review provides an overview of solution NMR techniques that can help analyse the early and transient events of conformational equilibrium of IDPs and folded proteins.
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Affiliation(s)
- Yoshiki Shigemitsu
- Laboratory of Structural and Molecular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya University, Aichi 464-8601, Japan
| | - Hidekazu Hiroaki
- Laboratory of Structural and Molecular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya University, Aichi 464-8601, Japan
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8
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Medeiros-Silva J, Jekhmane S, Baldus M, Weingarth M. Hydrogen bond strength in membrane proteins probed by time-resolved 1H-detected solid-state NMR and MD simulations. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2017; 87:80-85. [PMID: 28342732 DOI: 10.1016/j.ssnmr.2017.03.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Revised: 03/09/2017] [Accepted: 03/13/2017] [Indexed: 06/06/2023]
Abstract
1H-detected solid-state NMR in combination with 1H/2D exchange steps allows for the direct identification of very strong hydrogen bonds in membrane proteins. On the example of the membrane-embedded potassium channel KcsA, we quantify the longevity of such very strong hydrogen bonds by combining time-resolved 1H-detected solid-state NMR experiments and molecular dynamics simulations. In particular, we show that the carboxyl-side chain of the highly conserved residue Glu51 is involved in ultra-strong hydrogen bonds, which are fully-water-exposed and yet stable for weeks. The astonishing stability of these hydrogen bonds is important for the structural integrity of potassium channels, which we further corroborate by computational studies.
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Affiliation(s)
- João Medeiros-Silva
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Department of Chemistry, Utrecht University, Pandualaan 8, 3584 CH Utrecht, The Netherlands
| | - Shehrazade Jekhmane
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Department of Chemistry, Utrecht University, Pandualaan 8, 3584 CH Utrecht, The Netherlands
| | - Marc Baldus
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Department of Chemistry, Utrecht University, Pandualaan 8, 3584 CH Utrecht, The Netherlands
| | - Markus Weingarth
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Department of Chemistry, Utrecht University, Pandualaan 8, 3584 CH Utrecht, The Netherlands.
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9
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Chevelkov V, Giller K, Becker S, Lange A. Measurement of backbone hydrogen-deuterium exchange in the type III secretion system needle protein PrgI by solid-state NMR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2017; 283:110-116. [PMID: 28985499 DOI: 10.1016/j.jmr.2017.08.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 08/15/2017] [Accepted: 08/27/2017] [Indexed: 06/07/2023]
Abstract
In this report we present site-specific measurements of amide hydrogen-deuterium exchange rates in a protein in the solid state phase by MAS NMR. Employing perdeuteration, proton detection and a high external magnetic field we could adopt the highly efficient Relax-EXSY protocol previously developed for liquid state NMR. According to this method, we measured the contribution of hydrogen exchange on apparent 15N longitudinal relaxation rates in samples with differing D2O buffer content. Differences in the apparent T1 times allowed us to derive exchange rates for multiple residues in the type III secretion system needle protein.
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Affiliation(s)
- Veniamin Chevelkov
- Department of Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, 13125 Berlin, Germany
| | - Karin Giller
- Department of NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Stefan Becker
- Department of NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Adam Lange
- Department of Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, 13125 Berlin, Germany; Institut für Biologie, Humboldt-Universität zu Berlin, 10115 Berlin, Germany.
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10
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Claesen J, Burzykowski T. Computational methods and challenges in hydrogen/deuterium exchange mass spectrometry. MASS SPECTROMETRY REVIEWS 2017; 36:649-667. [PMID: 27602546 DOI: 10.1002/mas.21519] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 05/08/2016] [Accepted: 08/18/2016] [Indexed: 06/06/2023]
Abstract
Hydrogen/Deuterium exchange (HDX) has been applied, since the 1930s, as an analytical tool to study the structure and dynamics of (small) biomolecules. The popularity of using HDX to study proteins increased drastically in the last two decades due to the successful combination with mass spectrometry (MS). Together with this growth in popularity, several technological advances have been made, such as improved quenching and fragmentation. As a consequence of these experimental improvements and the increased use of protein-HDXMS, large amounts of complex data are generated, which require appropriate analysis. Computational analysis of HDXMS requires several steps. A typical workflow for proteins consists of identification of (non-)deuterated peptides or fragments of the protein under study (local analysis), or identification of the deuterated protein as a whole (global analysis); determination of the deuteration level; estimation of the protection extent or exchange rates of the labile backbone amide hydrogen atoms; and a statistically sound interpretation of the estimated protection extent or exchange rates. Several algorithms, specifically designed for HDX analysis, have been proposed. They range from procedures that focus on one specific step in the analysis of HDX data to complete HDX workflow analysis tools. In this review, we provide an overview of the computational methods and discuss outstanding challenges. © 2016 Wiley Periodicals, Inc. Mass Spec Rev 36:649-667, 2017.
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Affiliation(s)
- Jürgen Claesen
- I-BioStat, Hasselt University, Campus Diepenbeek, Agoralaan Gebouw D, Diepenbeek 3590, Belgium
| | - Tomasz Burzykowski
- I-BioStat, Hasselt University, Campus Diepenbeek, Agoralaan Gebouw D, Diepenbeek 3590, Belgium
- Statistics and Medical informatics Unit, Medical University of Bialystok, Białystok, Poland
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Balakrishnan S, Sarma SP. Engineering Aromatic–Aromatic Interactions To Nucleate Folding in Intrinsically Disordered Regions of Proteins. Biochemistry 2017; 56:4346-4359. [DOI: 10.1021/acs.biochem.7b00437] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Swati Balakrishnan
- Molecular
Biophysics Unit, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Siddhartha P. Sarma
- Molecular
Biophysics Unit, Indian Institute of Science, Bangalore, Karnataka 560012, India
- NMR
Research Center, Indian Institute of Science, Bangalore, Karnataka 560012, India
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12
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Englander SW, Mayne L, Kan ZY, Hu W. Protein Folding-How and Why: By Hydrogen Exchange, Fragment Separation, and Mass Spectrometry. Annu Rev Biophys 2016; 45:135-52. [PMID: 27145881 DOI: 10.1146/annurev-biophys-062215-011121] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Advanced hydrogen exchange (HX) methodology can now determine the structure of protein folding intermediates and their progression in folding pathways. Key developments over time include the HX pulse labeling method with nuclear magnetic resonance analysis, the fragment separation method, the addition to it of mass spectrometric (MS) analysis, and recent improvements in the HX MS technique and data analysis. Also, the discovery of protein foldons and their role supplies an essential interpretive link. Recent work using HX pulse labeling with MS analysis finds that a number of proteins fold by stepping through a reproducible sequence of native-like intermediates in an ordered pathway. The stepwise nature of the pathway is dictated by the cooperative foldon unit construction of the protein. The pathway order is determined by a sequential stabilization principle; prior native-like structure guides the formation of adjacent native-like structure. This view does not match the funneled energy landscape paradigm of a very large number of folding tracks, which was framed before foldons were known and is more appropriate for the unguided residue-level search to surmount an initial kinetic barrier rather than for the overall unfolded-state to native-state folding pathway.
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Affiliation(s)
- S Walter Englander
- Johnson Research Foundation, Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6059; , , ,
| | - Leland Mayne
- Johnson Research Foundation, Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6059; , , ,
| | - Zhong-Yuan Kan
- Johnson Research Foundation, Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6059; , , ,
| | - Wenbing Hu
- Johnson Research Foundation, Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6059; , , ,
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13
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Protein Structural Analysis via Mass Spectrometry-Based Proteomics. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 919:397-431. [PMID: 27975228 DOI: 10.1007/978-3-319-41448-5_19] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Modern mass spectrometry (MS) technologies have provided a versatile platform that can be combined with a large number of techniques to analyze protein structure and dynamics. These techniques include the three detailed in this chapter: (1) hydrogen/deuterium exchange (HDX), (2) limited proteolysis, and (3) chemical crosslinking (CX). HDX relies on the change in mass of a protein upon its dilution into deuterated buffer, which results in varied deuterium content within its backbone amides. Structural information on surface exposed, flexible or disordered linker regions of proteins can be achieved through limited proteolysis, using a variety of proteases and only small extents of digestion. CX refers to the covalent coupling of distinct chemical species and has been used to analyze the structure, function and interactions of proteins by identifying crosslinking sites that are formed by small multi-functional reagents, termed crosslinkers. Each of these MS applications is capable of revealing structural information for proteins when used either with or without other typical high resolution techniques, including NMR and X-ray crystallography.
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Abstract
Myriad biological processes proceed through states that defy characterization by conventional atomic-resolution structural biological methods. The invisibility of these 'dark' states can arise from their transient nature, low equilibrium population, large molecular weight, and/or heterogeneity. Although they are invisible, these dark states underlie a range of processes, acting as encounter complexes between proteins and as intermediates in protein folding and aggregation. New methods have made these states accessible to high-resolution analysis by nuclear magnetic resonance (NMR) spectroscopy, as long as the dark state is in dynamic equilibrium with an NMR-visible species. These methods - paramagnetic NMR, relaxation dispersion, saturation transfer, lifetime line broadening, and hydrogen exchange - allow the exploration of otherwise invisible states in exchange with a visible species over a range of timescales, each taking advantage of some unique property of the dark state to amplify its effect on a particular NMR observable. In this review, we introduce these methods and explore two specific techniques - paramagnetic relaxation enhancement and dark state exchange saturation transfer - in greater detail.
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Affiliation(s)
- Nicholas J. Anthis
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520, USA
| | - G. Marius Clore
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520, USA
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15
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Majumdar R, Middaugh C, Weis DD, Volkin DB. Hydrogen-Deuterium Exchange Mass Spectrometry as an Emerging Analytical Tool for Stabilization and Formulation Development of Therapeutic Monoclonal Antibodies. J Pharm Sci 2015; 104:327-45. [DOI: 10.1002/jps.24224] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Revised: 09/24/2014] [Accepted: 09/26/2014] [Indexed: 12/11/2022]
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16
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Vranken WF, Vuister GW, Bonvin AMJJ. NMR-based modeling and refinement of protein 3D structures. Methods Mol Biol 2015; 1215:351-380. [PMID: 25330971 DOI: 10.1007/978-1-4939-1465-4_16] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
NMR is a well-established method to characterize the structure and dynamics of biomolecules in solution. High-quality structures can now be produced thanks to both experimental advances and computational developments that incorporate new NMR parameters and improved protocols and force fields in the structure calculation and refinement process. In this chapter, we give a short overview of the various types of NMR data that can provide structural information, and then focus on the structure calculation methodology itself. We discuss and illustrate with tutorial examples "classical" structure calculation, refinement, and structure validation approaches.
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Affiliation(s)
- Wim F Vranken
- Department of Structural Biology, VIB Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, B-1050, Brussels, Belgium
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Engen JR, Wales TE. Analytical Aspects of Hydrogen Exchange Mass Spectrometry. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2015; 8:127-48. [PMID: 26048552 PMCID: PMC4989240 DOI: 10.1146/annurev-anchem-062011-143113] [Citation(s) in RCA: 102] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
This article reviews the analytical aspects of measuring hydrogen exchange by mass spectrometry (HX MS). We describe the nature of analytical selectivity in hydrogen exchange, then review the analytical tools required to accomplish fragmentation, separation, and the mass spectrometry measurements under restrictive exchange quench conditions. In contrast to analytical quantitation that relies on measurements of peak intensity or area, quantitation in HX MS depends on measuring a mass change with respect to an undeuterated or deuterated control, resulting in a value between zero and the maximum amount of deuterium that can be incorporated. Reliable quantitation is a function of experimental fidelity and to achieve high measurement reproducibility, a large number of experimental variables must be controlled during sample preparation and analysis. The method also reports on important qualitative aspects of the sample, including conformational heterogeneity and population dynamics.
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Affiliation(s)
- John R Engen
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115;
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Lopez J, Ahuja P, Landrieu I, Cantrelle FX, Huvent I, Lippens G. H/D exchange of a 15N labelled Tau fragment as measured by a simple Relax-EXSY experiment. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2014; 249:32-37. [PMID: 25462944 DOI: 10.1016/j.jmr.2014.10.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Revised: 10/03/2014] [Accepted: 10/06/2014] [Indexed: 06/04/2023]
Abstract
We present an equilibrium H/D exchange experiment to measure the exchange rates of labile amide protons in intrinsically unfolded proteins. By measuring the contribution of the H/D exchange to the apparent T1 relaxation rates in solvents of different D2O content, we can easily derive the rates of exchange for rapidly exchanging amide protons. The method does not require double isotope labelling, is sensitive, and requires limited fitting of the data. We demonstrate it on a functional fragment of Tau, and provide evidence for the hydrogen bond formation of the phosphate moiety of Ser214 with its own amide proton in the same fragment phosphorylated by the PKA kinase.
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Affiliation(s)
- Juan Lopez
- CNRS UMR 8576, Unité de Glycobiologie Structurale et Fonctionnelle, Université des Sciences et Technologies de Lille 1, 59655 Villeneuve d'Ascq Cedex, France
| | - Puneet Ahuja
- CNRS UMR 8576, Unité de Glycobiologie Structurale et Fonctionnelle, Université des Sciences et Technologies de Lille 1, 59655 Villeneuve d'Ascq Cedex, France
| | - Isabelle Landrieu
- CNRS UMR 8576, Unité de Glycobiologie Structurale et Fonctionnelle, Université des Sciences et Technologies de Lille 1, 59655 Villeneuve d'Ascq Cedex, France; CNRS USR 3078, Institut de Recherche Interdisciplinaire, Centre National de la Recherche Scientifique, 59655 Villeneuve d'Ascq, France
| | - François-Xavier Cantrelle
- CNRS UMR 8576, Unité de Glycobiologie Structurale et Fonctionnelle, Université des Sciences et Technologies de Lille 1, 59655 Villeneuve d'Ascq Cedex, France
| | - Isabelle Huvent
- CNRS UMR 8576, Unité de Glycobiologie Structurale et Fonctionnelle, Université des Sciences et Technologies de Lille 1, 59655 Villeneuve d'Ascq Cedex, France
| | - Guy Lippens
- CNRS UMR 8576, Unité de Glycobiologie Structurale et Fonctionnelle, Université des Sciences et Technologies de Lille 1, 59655 Villeneuve d'Ascq Cedex, France.
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Rennella E, Solyom Z, Brutscher B. Measuring hydrogen exchange in proteins by selective water saturation in (1)H- (15)N SOFAST/BEST-type experiments: advantages and limitations. JOURNAL OF BIOMOLECULAR NMR 2014; 60:99-107. [PMID: 25173410 DOI: 10.1007/s10858-014-9857-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Accepted: 08/22/2014] [Indexed: 06/03/2023]
Abstract
HET(ex)-SOFAST NMR (Schanda et al. in J Biomol NMR 33:199-211, 2006) has been proposed some years ago as a fast and sensitive method for semi-quantitative measurement of site-specific amide-water hydrogen exchange effects along the backbone of proteins. Here we extend this concept to BEST readout sequences that provide a better resolution at the expense of some loss in sensitivity. We discuss the theoretical background and implementation of the experiment, and demonstrate its performance for an intrinsically disordered protein, 2 well folded globular proteins, and a transiently populated folding intermediate state. We also provide a critical evaluation of the level of accuracy that can be obtained when extracting quantitative exchange rates from HET(ex) NMR measurements.
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Affiliation(s)
- Enrico Rennella
- Institut de Biologie Structurale, Université Grenoble 1, 71 avenue des Martyrs, 38044, Grenoble Cedex 9, France
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20
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Moulick R, Udgaonkar JB. Thermodynamic characterization of the unfolding of the prion protein. Biophys J 2014; 106:410-20. [PMID: 24461016 DOI: 10.1016/j.bpj.2013.11.4491] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Revised: 11/15/2013] [Accepted: 11/27/2013] [Indexed: 12/16/2022] Open
Abstract
The prion protein appears to be unusually susceptible to conformational change, and unlike nearly all other proteins, it can easily be made to convert to alternative misfolded conformations. To understand the basis of this structural plasticity, a detailed thermodynamic characterization of two variants of the mouse prion protein (moPrP), the full-length moPrP (23-231) and the structured C-terminal domain, moPrP (121-231), has been carried out. All thermodynamic parameters governing unfolding, including the changes in enthalpy, entropy, free energy, and heat capacity, were found to be identical for the two protein variants. The N-terminal domain remains unstructured and does not interact with the C-terminal domain in the full-length protein at pH 4. Moreover, the enthalpy and entropy of unfolding of moPrP (121-231) are similar in magnitude to values reported for other proteins of similar size. However, the protein has an unusually high native-state heat capacity, and consequently, the change in heat capacity upon unfolding is much lower than that expected for a protein of similar size. It appears, therefore, that the native state of the prion protein undergoes substantial fluctuations in enthalpy and hence, in structure.
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Affiliation(s)
- Roumita Moulick
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
| | - Jayant B Udgaonkar
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India.
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21
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Liuni P, Zhu S, Wilson DJ. Oxidative protein labeling with analysis by mass spectrometry for the study of structure, folding, and dynamics. Antioxid Redox Signal 2014; 21:497-510. [PMID: 24512178 DOI: 10.1089/ars.2014.5850] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
SIGNIFICANCE Analytical approaches that can provide insights into the mechanistic processes underlying protein folding and dynamics are few since the target analytes-high-energy structural intermediates-are short lived and often difficult to distinguish from coexisting structures. Folding "intermediates" can be populated at equilibrium using weakly denaturing solvents, but it is not clear that these species are identical to those that are transiently populated during folding under "native" conditions. Oxidative labeling with mass spectrometric analysis is a powerful alternative for structural characterization of proteins and transient protein species based on solvent exposure at specific sites. RECENT ADVANCES Oxidative labeling is increasingly used with exceedingly short (μs) labeling pulses, both to minimize the occurrence of artifactual structural changes due to the incorporation of label and to detect short-lived species. The recent introduction of facile photolytic approaches for producing reactive oxygen species is an important technological advance that will enable more widespread adoption of the technique. CRITICAL ISSUES The most common critique of oxidative labeling data is that even with brief labeling pulses, covalent modification of the protein may cause significant artifactual structural changes. FUTURE DIRECTIONS While the oxidative labeling with the analysis by mass spectrometry is mature enough that most basic methodological issues have been addressed, a complete systematic understanding of side chain reactivity in the context of intact proteins is an avenue for future work. Specifically, there remain issues around the impact of primary sequence and side chain interactions on the reactivity of "solvent-exposed" residues. Due to its analytical power, wide range of applications, and relative ease of implementation, oxidative labeling is an increasingly important technique in the bioanalytical toolbox.
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Affiliation(s)
- Peter Liuni
- 1 Department of Chemistry, York University , Toronto, Canada
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Nayidu NK, Tan Y, Taheri A, Li X, Bjorndahl TC, Nowak J, Wishart DS, Hegedus D, Gruber MY. Brassica villosa, a system for studying non-glandular trichomes and genes in the Brassicas. PLANT MOLECULAR BIOLOGY 2014; 85:519-39. [PMID: 24831512 DOI: 10.1007/s11103-014-0201-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2013] [Accepted: 05/11/2014] [Indexed: 05/18/2023]
Abstract
Brassica villosa is a wild Brassica C genome species with very dense trichome coverage and strong resistance to many insect pests of Brassica oilseeds and vegetables. Transcriptome analysis of hairy B. villosa leaves indicated higher expression of several important trichome initiation genes compared with glabrous B. napus leaves and consistent with the Arabidopsis model of trichome development. However, transcripts of the TRY inhibitory gene in hairy B. villosa were surprisingly high relative to B. napus and relative transcript levels of SAD2, EGL3, and several XIX genes were low, suggesting potential ancillary or less important trichome-related roles for these genes in Brassica species compared with Arabidopsis. Several antioxidant, calcium, non-calcium metal and secondary metabolite genes also showed differential expression between these two species. These coincided with accumulation of two alkaloid-like compounds, high levels of calcium, and other metals in B. villosa trichomes that are correlated with the known tolerance of B. villosa to high salt and the calcium-rich natural habitat of this wild species. This first time report on the isolation of large amounts of pure B. villosa trichomes, on trichome content, and on relative gene expression differences in an exceptionally hairy Brassica species compared with a glabrous species opens doors for the scientific community to understand trichome gene function in the Brassicas and highlights the potential of B. villosa as a trichome research platform.
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Affiliation(s)
- Naghabushana K Nayidu
- Saskatoon Research Centre, Agriculture and Agri-Food Canada, 107 Science Place, Saskatoon, SK, S7N0X2, Canada,
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23
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Richardt A, Mrestani-Klaus C, Bordusa F. Impact of ionic liquids on the structure of peptides proved by HR-MAS NMR spectroscopy. J Mol Liq 2014. [DOI: 10.1016/j.molliq.2013.12.027] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Sevy AM, Healey JF, Deng W, Spiegel PC, Meeks SL, Li R. Epitope mapping of inhibitory antibodies targeting the C2 domain of coagulation factor VIII by hydrogen-deuterium exchange mass spectrometry. J Thromb Haemost 2013; 11:2128-36. [PMID: 24152306 PMCID: PMC3947443 DOI: 10.1111/jth.12433] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2013] [Indexed: 01/18/2023]
Abstract
BACKGROUND The development of anti-factor VIII antibodies (inhibitors) is a significant complication in the management of patients with hemophilia A, leading to significant increases in morbidity and treatment cost. Using a panel of mAbs against different epitopes on FVIII, we have recently shown that epitope specificity, inhibitor kinetics and time to maximum inhibition are more important than inhibitor titer in predicting responses to FVIII and the combination of FVIII and recombinant FVIIa. In particular, a subset of high-titer inhibitors responded to high-dose FVIII, which would not be predicted on the basis of their inhibitor titer alone. Thus, the ability to quickly map the epitope spectrum of patient plasma with a clinically feasible assay may fundamentally change how clinicians approach the treatment of high-titer inhibitor patients. OBJECTIVES To map the epitopes of anti-FVIII mAbs, three of which are classic inhibitors and one of which is a non-classic inhibitor, by the use of hydrogen-deuterium exchange coupled with mass spectrometry (HDX-MS). METHODS The binding epitopes of four mAbs targeting the FVIII C2 domain were mapped with HDX-MS. RESULTS The epitopes determined with HDX-MS are consistent with those obtained earlier through structural characterization and antibody competition assays. In addition, classic and non-classic inhibitor epitopes could be distinguished by the use of a limited subset of C2 domain-derived peptic fragments. CONCLUSION Our results demonstrate the effectiveness and robustness of the HDX-MS method for epitope mapping, and suggest a potential role of rapid mapping of FVIII inhibitor epitopes in facilitating individualized treatment of inhibitor patients.
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Affiliation(s)
- Alexander M. Sevy
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA
| | - John F. Healey
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA
| | - Wei Deng
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA
| | - P. Clint Spiegel
- Department of Chemistry, Western Washington University, Bellingham, WA, USA
| | - Shannon L. Meeks
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA
| | - Renhao Li
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA
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25
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Abstract
Protein stability is usually studied in simple buffered solutions, but most proteins function inside cells, where the heterogeneous and crowded environment presents a complex, nonideal system. Proteins are expected to behave differently under cellular crowding owing to two types of contacts: hard-core repulsions and weak, chemical interactions. The effect of hard-core repulsions is purely entropic, resulting in volume exclusion owing to the mere presence of the crowders. The weak interactions can be repulsive or attractive, thus enhancing or diminishing the excluded volume, respectively. We used a reductionist approach to assess the effects of intracellular crowding. Escherichia coli cytoplasm was dialyzed, lyophilized, and resuspended at two concentrations. NMR-detected amide proton exchange was then used to quantify the stability of the globular protein chymotrypsin inhibitor 2 (CI2) in these crowded solutions. The cytosol destabilizes CI2, and the destabilization increases with increasing cytosol concentration. This observation shows that the cytoplasm interacts favorably, but nonspecifically, with CI2, and these interactions overcome the stabilizing hard-core repulsions. The effects of the cytosol are even stronger than those of homogeneous protein crowders, reinforcing the biological significance of weak, nonspecific interactions.
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27
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Huber R. “Wie ich zur Proteaseforschung kam oder, richtiger gesagt, wie die Proteaseforschung zu mir kam”. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201205629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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28
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Krishnan VV, Murali N. Radiation damping in modern NMR experiments: progress and challenges. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2013; 68:41-57. [PMID: 23398972 PMCID: PMC3644564 DOI: 10.1016/j.pnmrs.2012.06.001] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Accepted: 06/07/2012] [Indexed: 05/12/2023]
Affiliation(s)
- V V Krishnan
- Department of Chemistry, California State University, Fresno, CA 93740, USA.
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29
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Huber R. "How I chose research on proteases or, more correctly, how it chose me". Angew Chem Int Ed Engl 2012. [PMID: 23208749 DOI: 10.1002/anie.201205629] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Robert Huber
- Max-Planck-Institut für Biochemie, Martinsried, Germany
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30
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Rob T, Liuni P, Gill PK, Zhu S, Balachandran N, Berti PJ, Wilson DJ. Measuring dynamics in weakly structured regions of proteins using microfluidics-enabled subsecond H/D exchange mass spectrometry. Anal Chem 2012; 84:3771-9. [PMID: 22458633 DOI: 10.1021/ac300365u] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
This work introduces an integrated microfluidic device for measuring rapid H/D exchange (HDX) in proteins. By monitoring backbone amide HDX on the millisecond to low second time scale, we are able to characterize conformational dynamics in weakly structured regions, such as loops and molten globule-like domains that are inaccessible in conventional HDX experiments. The device accommodates the entire MS-based HDX workflow on a single chip with residence times sufficiently small (ca. 8 s) that back-exchange is negligible (≤5%), even without cooling. Components include an adjustable position capillary mixer providing a variable-time labeling pulse, a static mixer for HDX quenching, a proteolytic microreactor for rapid protein digestion, and on-chip electrospray ionization (ESI). In the present work, we characterize device performance using three model systems, each illustrating a different application of 'time-resolved' HDX. Ubiquitin is used to illustrate a crude, high throughput structural analysis based on a single subsecond HDX time-point. In experiments using cytochrome c, we distinguish dynamic behavior in loops, establishing a link between flexibility and interactions with the heme prosthetic group. Finally, we localize an unusually high 'burst-phase' of HDX in the large tetrameric enzyme DAHP synthase to a 'molten globule-like' region surrounding the active site.
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Affiliation(s)
- Tamanna Rob
- Department of Chemistry, York University, Toronto, Ontario, Canada
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31
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Wang S, Shi L, Kawamura I, Brown LS, Ladizhansky V. Site-specific solid-state NMR detection of hydrogen-deuterium exchange reveals conformational changes in a 7-helical transmembrane protein. Biophys J 2011; 101:L23-5. [PMID: 21806918 DOI: 10.1016/j.bpj.2011.06.035] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Revised: 05/18/2011] [Accepted: 06/23/2011] [Indexed: 10/17/2022] Open
Abstract
Solid-state NMR spectroscopy is an efficient tool for following conformational dynamics of membrane proteins at atomic resolution. We used this technique for the site-specific detection of light-induced hydrogen-deuterium exchange in the lipid-embedded heptahelical transmembrane photosensor Anabaena sensory rhodopsin to pinpoint the location of its conformational changes upon activation. We show that the light-induced conformational changes result in a dramatic, but localized, increase in the exchange in the transmembrane regions. Most notably, the cytoplasmic half of helix G and the cytoplasmic ends of helices B and C exchange more extensively, probably as a result of their relative displacement in the activated state, allowing water to penetrate into the core of the protein. These light-induced rearrangements must provide the structural basis for the photosensory function of Anabaena sensory rhodopsin.
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Affiliation(s)
- Shenlin Wang
- Department of Physics and Biophysics Interdepartmental Group, University of Guelph, Guelph, Ontario, Canada
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32
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Mayne L, Kan ZY, Chetty PS, Ricciuti A, Walters BT, Englander SW. Many overlapping peptides for protein hydrogen exchange experiments by the fragment separation-mass spectrometry method. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2011; 22:1898-905. [PMID: 21952777 PMCID: PMC3396559 DOI: 10.1007/s13361-011-0235-4] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Revised: 08/11/2011] [Accepted: 08/12/2011] [Indexed: 05/19/2023]
Abstract
Measurement of the naturally occurring hydrogen exchange (HX) behavior of proteins can in principle provide highly resolved thermodynamic and kinetic information on protein structure, dynamics, and interactions. The HX fragment separation-mass spectrometry method (HX-MS) is able to measure hydrogen exchange in biologically important protein systems that are not accessible to NMR methods. In order to achieve high structural resolution in HX-MS experiments, it will be necessary to obtain many sequentially overlapping peptide fragments and be able to identify and analyze them efficiently and accurately by mass spectrometry. This paper describes operations which, when applied to four different proteins ranging in size from 140 to 908 residues, routinely provides hundreds of useful unique peptides, covering the entire protein length many times over. Coverage in terms of the average number of peptide fragments that span each amino acid exceeds 10. The ability to achieve these results required the integrated application of experimental methods that are described here and a computer analysis program, called ExMS, described in a following paper.
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Affiliation(s)
- Leland Mayne
- Johnson Research Foundation, Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, 1006 Stellar-Chance Labs, 422 Curie Boulevard, Philadelphia, PA 19104, USA.
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Takeda M, Jee J, Ono AM, Terauchi T, Kainosho M. Hydrogen Exchange Study on the Hydroxyl Groups of Serine and Threonine Residues in Proteins and Structure Refinement Using NOE Restraints with Polar Side-Chain Groups. J Am Chem Soc 2011; 133:17420-7. [DOI: 10.1021/ja206799v] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Mitsuhiro Takeda
- Structural Biology Research Center, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - JunGoo Jee
- Center for Priority Areas, Graduate School of Science and Technology, Tokyo Metropolitan University, 1-1 minami-ohsawa, Hachioji 192-0397, Japan
| | - Akira M. Ono
- Center for Priority Areas, Graduate School of Science and Technology, Tokyo Metropolitan University, 1-1 minami-ohsawa, Hachioji 192-0397, Japan
| | - Tsutomu Terauchi
- Center for Priority Areas, Graduate School of Science and Technology, Tokyo Metropolitan University, 1-1 minami-ohsawa, Hachioji 192-0397, Japan
| | - Masatsune Kainosho
- Structural Biology Research Center, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
- Center for Priority Areas, Graduate School of Science and Technology, Tokyo Metropolitan University, 1-1 minami-ohsawa, Hachioji 192-0397, Japan
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Hanashima S, Kato K, Yamaguchi Y. 13C-NMR quantification of proton exchange at LewisX hydroxyl groups in water. Chem Commun (Camb) 2011; 47:10800-2. [PMID: 21892456 DOI: 10.1039/c1cc13310a] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
NMR-based analysis of glycans by directly observing hydroxyl protons has been difficult because of their inherently fast exchange with water. We observed hydroxyl proton exchanges in a LewisX-LewisX interaction by using deuterium isotope shifts on (13)C-NMR. This strategy is suitable for analyzing weak interactions by identifying involved protons.
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Affiliation(s)
- Shinya Hanashima
- Structural Glycobiology Team, RIKEN Advanced Science Institute, 2-1 Hirosawa, Wako-shi, 351-0198 Saitama, Japan
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35
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Fan JS, Lim J, Yu B, Yang D. Measurement of amide hydrogen exchange rates with the use of radiation damping. JOURNAL OF BIOMOLECULAR NMR 2011; 51:151-162. [PMID: 21947923 DOI: 10.1007/s10858-011-9549-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2011] [Accepted: 07/07/2011] [Indexed: 05/31/2023]
Abstract
A simple method for measuring amide hydrogen exchange rates is presented, which is based on the selective inversion of water magnetization with the use of radiation damping. Simulations show that accurate exchange rates can be measured despite the complications of radiation damping and cross relaxation to the exchange process between amide and water protons. This method cannot eliminate the contributions of the exchange-relayed NOE and direct NOE to the measured exchange rates, but minimize the direct NOE contribution. In addition, the amides with a significant amount of such indirect contributions are possible to be identified from the shape of the exchange peak intensity profiles or/and from the apparent relaxation rates of amide protons which are extracted from fitting the intensity profiles to an equation established here for our experiment. The method was tested on ubiquitin and also applied to an acyl carrier protein. The amide exchange rates for the acyl carrier protein at two pHs indicate that the entire protein is highly dynamic on the second timescale. Low protection factors for the residues in the regular secondary structural elements also suggest the presence of invisible unfolded species. The highly dynamic nature of the acyl carrier protein may be crucial for its interactions with its substrate and enzymes.
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Affiliation(s)
- Jing-Song Fan
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Singapore
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36
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Structural insights into conformational changes of a cyclic nucleotide-binding domain in solution from Mesorhizobium loti K1 channel. Proc Natl Acad Sci U S A 2011; 108:6121-6. [PMID: 21430265 DOI: 10.1073/pnas.1015890108] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cyclic nucleotide-sensitive ion channels, known as HCN and CNG channels, are activated by binding of ligands to a domain (CNBD) located on the cytoplasmic side of the channel. The underlying mechanisms are not well understood. To elucidate the gating mechanism, structures of both the ligand-free and -bound CNBD are required. Several crystal structures of the CNBD from HCN2 and a bacterial CNG channel (MloK1) have been solved. However, for HCN2, the cAMP-free and -bound state did not reveal substantial structural rearrangements. For MloK1, structural information for the cAMP-free state has only been gained from mutant CNBDs. Moreover, in the crystal, the CNBD molecules form an interface between dimers, proposed to be important for allosteric channel gating. Here, we have determined the solution structure by NMR spectroscopy of the cAMP-free wild-type CNBD of MloK1. A comparison of the solution structure of cAMP-free and -bound states reveals large conformational rearrangement on ligand binding. The two structures provide insights on a unique set of conformational events that accompany gating within the ligand-binding site.
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37
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del Amo JML, Fink U, Reif B. Quantification of protein backbone hydrogen-deuterium exchange rates by solid state NMR spectroscopy. JOURNAL OF BIOMOLECULAR NMR 2010; 48:203-212. [PMID: 20960033 DOI: 10.1007/s10858-010-9450-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2010] [Accepted: 09/21/2010] [Indexed: 05/30/2023]
Abstract
We present the quantification of backbone amide hydrogen-deuterium exchange rates (HDX) for immobilized proteins. The experiments make use of the deuterium isotope effect on the amide nitrogen chemical shift, as well as on proton dilution by deuteration. We find that backbone amides in the microcrystalline α-spectrin SH3 domain exchange rather slowly with the solvent (with exchange rates negligible within the individual (15)N-T (1) timescales). We observed chemical exchange for 6 residues with HDX exchange rates in the range from 0.2 to 5 s(-1). Backbone amide (15)N longitudinal relaxation times that we determined previously are not significantly affected for most residues, yielding no systematic artifacts upon quantification of backbone dynamics (Chevelkov et al. 2008b). Significant exchange was observed for the backbone amides of R21, S36 and K60, as well as for the sidechain amides of N38, N35 and for W41ε. These residues could not be fit in our previous motional analysis, demonstrating that amide proton chemical exchange needs to be considered in the analysis of protein dynamics in the solid-state, in case D(2)O is employed as a solvent for sample preparation. Due to the intrinsically long (15)N relaxation times in the solid-state, the approach proposed here can expand the range of accessible HDX rates in the intermediate regime that is not accessible so far with exchange quench and MEXICO type experiments.
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Shaw BF, Arthanari H, Narovlyansky M, Durazo A, Frueh DP, Pollastri MP, Lee A, Bilgicer B, Gygi SP, Wagner G, Whitesides GM. Neutralizing positive charges at the surface of a protein lowers its rate of amide hydrogen exchange without altering its structure or increasing its thermostability. J Am Chem Soc 2010; 132:17411-25. [PMID: 21090618 DOI: 10.1021/ja9067035] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
This paper combines two techniques--mass spectrometry and protein charge ladders--to examine the relationship between the surface charge and hydrophobicity of a representative globular protein (bovine carbonic anhydrase II; BCA II) and its rate of amide hydrogen-deuterium (H/D) exchange. Mass spectrometric analysis indicated that the sequential acetylation of surface lysine-ε-NH3(+) groups--a type of modification that increases the net negative charge and hydrophobicity of the surface of BCA II without affecting its secondary or tertiary structure--resulted in a linear decrease in the aggregate rate of amide H/D exchange at pD 7.4, 15 °C. According to analysis with MS, the acetylation of each additional lysine generated between 1.4 and 0.9 additional hydrogens that are protected from H/D exchange during the 2 h exchange experiment at 15 °C, pD 7.4. NMR spectroscopy demonstrated that none of the hydrogen atoms which became protected upon acetylation were located on the side chain of the acetylated lysine residues (i.e., lys-ε-NHCOCH3) but were instead located on amide NHCO moieties in the backbone. The decrease in rate of exchange associated with acetylation paralleled a decrease in thermostability: the most slowly exchanging rungs of the charge ladder were the least thermostable (as measured by differential scanning calorimetry). This observation--that faster rates of exchange are associated with slower rates of denaturation--is contrary to the usual assumptions in protein chemistry. The fact that the rates of H/D exchange were similar for perbutyrated BCA II (e.g., [lys-ε-NHCO(CH2)2CH3]18) and peracetylated BCA II (e.g., [lys-ε-NHCOCH3]18) suggests that the electrostatic charge is more important than the hydrophobicity of surface groups in determining the rate of H/D exchange. These electrostatic effects on the kinetics of H/D exchange could complicate (or aid) the interpretation of experiments in which H/D exchange methods are used to probe the structural effects of non-isoelectric perturbations to proteins (i.e., phosphorylation, acetylation, or the binding of the protein to an oligonucleotide or to another charged ligand or protein).
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Affiliation(s)
- Bryan F Shaw
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA.
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Edwards AA, Tipton JD, Brenowitz MD, Emmett MR, Marshall AG, Evans GB, Tyler PC, Schramm VL. Conformational states of human purine nucleoside phosphorylase at rest, at work, and with transition state analogues. Biochemistry 2010; 49:2058-67. [PMID: 20108972 DOI: 10.1021/bi902041j] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Human purine nucleoside phosphorylase (PNP) is a homotrimer binding tightly to the transition state analogues Immucillin-H (ImmH; K(d) = 56 pM) and DATMe-ImmH-Immucillin-H (DATMe-ImmH; K(d) = 8.6 pM). ImmH binds with a larger entropic penalty than DATMe-ImmH, a chemically more flexible inhibitor. The testable hypothesis is that PNP conformational states are more relaxed (dynamic) with DATMe-ImmH, despite tighter binding than with ImmH. PNP conformations are probed by peptide amide deuterium exchange (HDX) using liquid chromatography high-resolution Fourier transform ion cyclotron resonance mass spectrometry and by sedimentation rates. Catalytically equilibrating Michaelis complexes (PNP.PO(4).inosine <--> PNP.Hx.R-1-P) and inhibited complexes (PNP.PO(4).DATMe-ImmH and PNP.PO(4).ImmH) show protection from HDX at 9, 13, and 15 sites per subunit relative to resting PNP (PNP.PO(4)) in extended incubations. The PNP.PO(4).ImmH complex is more compact (by sedimentation rate) than the other complexes. HDX kinetic analysis of ligand-protected sites corresponds to peptides near the catalytic sites. HDX and sedimentation results establish that PNP protein conformation (dynamic motion) correlates more closely with entropy of binding than with affinity. Catalytically active turnover with saturated substrate sites causes less change in HDX and sedimentation rates than binding of transition state analogues. DATMe-ImmH more closely mimics the transition of human PNP than does ImmH and achieves strong binding interactions at the catalytic site while causing relatively modest alterations of the protein dynamic motion. Transition state analogues causing the most rigid, closed protein conformation are therefore not necessarily the most tightly bound. Close mimics of the transition state are hypothesized to retain enzymatic dynamic motions related to transition state formation.
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Affiliation(s)
- Achelle A Edwards
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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Chevelkov V, Xue Y, Rao DK, Forman-Kay JD, Skrynnikov NR. 15N H/D-SOLEXSY experiment for accurate measurement of amide solvent exchange rates: application to denatured drkN SH3. JOURNAL OF BIOMOLECULAR NMR 2010; 46:227-244. [PMID: 20195703 DOI: 10.1007/s10858-010-9398-8] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2009] [Accepted: 02/03/2010] [Indexed: 05/28/2023]
Abstract
Amide solvent exchange rates are regarded as a valuable source of information on structure/dynamics of unfolded (disordered) proteins. Proton-based saturation transfer experiments, normally used to measure solvent exchange, are known to meet some serious difficulties. The problems mainly arise from the need to (1) manipulate water magnetization and (2) discriminate between multiple magnetization transfer pathways that occur within the proton pool. Some of these issues are specific to unfolded proteins. For example, the compensation scheme used to cancel the Overhauser effect in the popular CLEANEX experiment is not designed for use with unfolded proteins. In this report we describe an alternative experimental strategy, where amide (15)N is used as a probe of solvent exchange. The experiment is performed in 50% H(2)O-50% D(2)O solvent and is based on the (HACACO)NH pulse sequence. The resulting spectral map is fully equivalent to the conventional HSQC. To fulfill its purpose, the experiment monitors the conversion of deuterated species, (15)N(D), into protonated species, (15)N(H), as effected by the solvent exchange. Conceptually, this experiment is similar to EXSY which prompted the name of (15)N(H/D)-SOLEXSY (SOLvent EXchange SpectroscopY). Of note, our experimental scheme, which relies on nitrogen rather than proton to monitor solvent exchange, is free of the complications described above. The developed pulse sequence was used to measure solvent exchange rates in the chemically denatured state of the drkN SH3 domain. The results were found to correlate well with the CLEANEX-PM data, r = 0.97, thus providing a measure of validation for both techniques. When the experimentally measured exchange rates are converted into protection factors, most of the values fall in the range 0.5-2, consistent with random-coil behavior. However, elevated values, ca. 5, are obtained for residues R38 and A39, as well as the side-chain indole of W36. This is surprising, given that high protection factors imply hydrogen bonding or hydrophobic burial not expected to occur in a chemically denatured state of a protein. We, therefore, hypothesized that elevated protection factors are an artefact arising from the calculation of the reference (random-coil) exchange rates. To confirm this hypothesis, we prepared samples of several short peptides derived from the sequence of the drkN SH3 domain; these samples were used to directly measure the reference exchange rates. The revised protection factors obtained in this manner proved to be close to 1.0. These results also have implications for the more compact unfolded state of drkN SH3, which appears to be fully permeable to water as well, with no manifestations of hydrophobic burial.
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Affiliation(s)
- Veniamin Chevelkov
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN, 47907-2084, USA
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Takeda M, Jee J, Ono AM, Terauchi T, Kainosho M. Hydrogen Exchange Rate of Tyrosine Hydroxyl Groups in Proteins As Studied by the Deuterium Isotope Effect on Cζ Chemical Shifts. J Am Chem Soc 2009; 131:18556-62. [DOI: 10.1021/ja907911y] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Mitsuhiro Takeda
- Structural Biology Research Center, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602, Japan, and Center of Priority Areas, Graduate School of Science and Technology, Tokyo Metropolitan University, 1-1 Minami-ohsawa, Hachioji, 192-0397, Japan
| | - JunGoo Jee
- Structural Biology Research Center, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602, Japan, and Center of Priority Areas, Graduate School of Science and Technology, Tokyo Metropolitan University, 1-1 Minami-ohsawa, Hachioji, 192-0397, Japan
| | - Akira Mei Ono
- Structural Biology Research Center, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602, Japan, and Center of Priority Areas, Graduate School of Science and Technology, Tokyo Metropolitan University, 1-1 Minami-ohsawa, Hachioji, 192-0397, Japan
| | - Tsutomu Terauchi
- Structural Biology Research Center, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602, Japan, and Center of Priority Areas, Graduate School of Science and Technology, Tokyo Metropolitan University, 1-1 Minami-ohsawa, Hachioji, 192-0397, Japan
| | - Masatsune Kainosho
- Structural Biology Research Center, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602, Japan, and Center of Priority Areas, Graduate School of Science and Technology, Tokyo Metropolitan University, 1-1 Minami-ohsawa, Hachioji, 192-0397, Japan
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Durazo A, Shaw BF, Chattopadhyay M, Faull KF, Nersissian AM, Valentine JS, Whitelegge JP. Metal-free superoxide dismutase-1 and three different amyotrophic lateral sclerosis variants share a similar partially unfolded beta-barrel at physiological temperature. J Biol Chem 2009; 284:34382-9. [PMID: 19805550 DOI: 10.1074/jbc.m109.052076] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The structure and unfolding of metal-free (apo) human wild-type SOD1 and three pathogenic variants of SOD1 (A4V, G93R, and H48Q) that cause familial amyotrophic lateral sclerosis have been studied with amide hydrogen/deuterium exchange and mass spectrometry. The results indicate that a significant proportion of each of these proteins exists in solution in a conformation in which some strands of the beta-barrel (i.e. beta2) are well protected from exchange at physiological temperature (37 degrees C), whereas other strands (i.e. beta3 and beta4) appear to be unprotected from hydrogen/deuterium exchange. Moreover, the thermal unfolding of these proteins does not result in the uniform incorporation of deuterium throughout the polypeptide but involves the local unfolding of different residues at different temperatures. Some regions of the proteins (i.e. the "Greek key" loop, residues 104-116) unfold at a significantly higher temperature than other regions (i.e. beta3 and beta4, residues 21-53). Together, these results show that human wild-type apo-SOD1 and variants have a partially unfolded beta-barrel at physiological temperature and unfold non-cooperatively.
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Affiliation(s)
- Armando Durazo
- Department of Chemistry and Biochemistry, UCLA, Los Angeles, California 90095, USA
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Gledhill JM, Walters BT, Wand AJ. AMORE-HX: a multidimensional optimization of radial enhanced NMR-sampled hydrogen exchange. JOURNAL OF BIOMOLECULAR NMR 2009; 45:233-9. [PMID: 19633974 PMCID: PMC3042283 DOI: 10.1007/s10858-009-9357-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2009] [Accepted: 06/29/2009] [Indexed: 05/19/2023]
Abstract
The Cartesian sampled three-dimensional HNCO experiment is inherently limited in time resolution and sensitivity for the real time measurement of protein hydrogen exchange. This is largely overcome by use of the radial HNCO experiment that employs the use of optimized sampling angles. The significant practical limitation presented by use of three-dimensional data is the large data storage and processing requirements necessary and is largely overcome by taking advantage of the inherent capabilities of the 2D-FT to process selective frequency space without artifact or limitation. Decomposition of angle spectra into positive and negative ridge components provides increased resolution and allows statistical averaging of intensity and therefore increased precision. Strategies for averaging ridge cross sections within and between angle spectra are developed to allow further statistical approaches for increasing the precision of measured hydrogen occupancy. Intensity artifacts potentially introduced by over-pulsing are effectively eliminated by use of the BEST approach.
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Affiliation(s)
| | | | - A. Joshua Wand
- To whom correspondence should be addressed. , Contact Information: Professor A. J. Wand, Department of Biochemistry & Biophysics, University of Pennsylvania, 905 Stellar-Chance Laboratories, 422 Curie Blvd., Philadelphia, PA 19104-6059, telephone: 215-573-7288, facsimile: 215-573-7290
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Umetsu Y, Aizawa T, Muto K, Yamamoto H, Kamiya M, Kumaki Y, Mizuguchi M, Demura M, Hayakawa Y, Kawano K. C-terminal elongation of growth-blocking peptide enhances its biological activity and micelle binding affinity. J Biol Chem 2009; 284:29625-34. [PMID: 19710009 DOI: 10.1074/jbc.m109.011148] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Growth-blocking peptide (GBP) is a hormone-like peptide that suppresses the growth of the host armyworm. Although the 23-amino acid GBP (1-23 GBP) is expressed in nonparasitized armyworm plasma, the parasitization by wasp produces the 28-amino acid GBP (1-28 GBP) through an elongation of the C-terminal amino acid sequence. In this study, we characterized the GBP variants, which consist of various lengths of the C-terminal region, by comparing their biological activities and three-dimensional structures. The results of an injection study indicate that 1-28 GBP most strongly suppresses larval growth. NMR analysis shows that these peptides have basically the same tertiary structures and that the extension of the C-terminal region is disordered. However, the C-terminal region of 1-28 GBP undergoes a conformational transition from a random coiled state to an alpha-helical state in the presence of dodecylphosphocholine micelles. This suggests that binding of the C-terminal region would affect larval growth activity.
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Affiliation(s)
- Yoshitaka Umetsu
- Division of Biological Sciences, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan
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45
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NMR analysis of native-state protein conformational flexibility by hydrogen exchange. Methods Mol Biol 2009; 490:285-310. [PMID: 19157088 DOI: 10.1007/978-1-59745-367-7_12] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/21/2023]
Abstract
The rate of hydrogen exchange for the most protected amides of a protein is widely used to provide an estimate of global conformational stability by analyzing the exchange kinetics in the unfolded state in terms of model peptide exchange rates. The exchange behavior of the other amides of the protein which do not exchange via a global unfolding mechanism can provide insight into the smaller-scale conformational transitions that facilitate access to solvent as required for the exchange reaction. However, since the residual tertiary structure in the exchange-competent conformation can modulate the chemistry of the exchange reaction, equilibrium values estimated from normalization with model peptide rates are open to question. To overcome this limitation, the most robust approaches utilize differential analyses as a function of experimental variables such as denaturant concentration, temperature, pH, and mutational variation. Practical aspects of these various differential analysis techniques are considered with illustrations drawn from the literature.
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46
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Huang JR, Hsu STD, Christodoulou J, Jackson SE. The extremely slow-exchanging core and acid-denatured state of green fluorescent protein. HFSP JOURNAL 2008; 2:378-87. [PMID: 19436495 DOI: 10.2976/1.2976660] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2008] [Accepted: 07/07/2008] [Indexed: 11/19/2022]
Abstract
Green fluorescent protein (GFP) is a large protein with a complex eleven-stranded beta-barrel structure. Previous studies have shown that it has a complex energy landscape for folding on which there are several intermediate states and a denatured state with significant residual structure. Here, we use two different types of HD exchange measurement and nuclear magnetic resonance (NMR) techniques to probe the energy landscape for folding of GFP in further detail. HD exchange experiments were performed over a wide range of conditions including different concentrations of denaturant. Results show that the penetration model dominates the exchange mechanism, consistent with the known stability and slow unfolding kinetics of GFP. HD exchange experiments at high pH establish that there is an extremely slow-exchanging superstable core of amide protons in GFP that are clustered and located in beta-strands 1, 2, 4, 5, and 6. These residues form part of a mini-beta-sheet which we propose constitutes a folding nucleus. Using a pulsed-labeling strategy, the acid-denatured state has been investigated and the residual structure observed in earlier studies shown to locate to beta-strands 1 and 3. There is some evidence that this residual structure is stabilized by a localized hydrophobic collapse of the polypeptide chain.
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48
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Gao C, Wijesinha-Bettoni R, Wilde PJ, Mills ENC, Smith LJ, Mackie AR. Surface Properties Are Highly Sensitive to Small pH Induced Changes in the 3-D Structure of α-Lactalbumin. Biochemistry 2008; 47:1659-66. [DOI: 10.1021/bi700999r] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Chunli Gao
- Structuring Food for Health Programme, Institute of Food Research, Norwich Research Park, Colney NR4 7UA, U.K., and Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K
| | - Ramani Wijesinha-Bettoni
- Structuring Food for Health Programme, Institute of Food Research, Norwich Research Park, Colney NR4 7UA, U.K., and Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K
| | - Peter J. Wilde
- Structuring Food for Health Programme, Institute of Food Research, Norwich Research Park, Colney NR4 7UA, U.K., and Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K
| | - E. N. Clare Mills
- Structuring Food for Health Programme, Institute of Food Research, Norwich Research Park, Colney NR4 7UA, U.K., and Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K
| | - Lorna J. Smith
- Structuring Food for Health Programme, Institute of Food Research, Norwich Research Park, Colney NR4 7UA, U.K., and Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K
| | - Alan R. Mackie
- Structuring Food for Health Programme, Institute of Food Research, Norwich Research Park, Colney NR4 7UA, U.K., and Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K
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Fuentes G, van Dijk ADJ, Bonvin AMJJ. Nuclear magnetic resonance-based modeling and refinement of protein three-dimensional structures and their complexes. Methods Mol Biol 2008; 443:229-255. [PMID: 18446291 DOI: 10.1007/978-1-59745-177-2_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Nuclear magnetic resonance (NMR) has become a well-established method to characterize the structures of biomolecules in solution. High-quality structures are now produced, thanks to both experimental and computational developments, allowing the use of new NMR parameters and improved protocols and force fields in structure calculation and refinement. In this chapter, we give a short overview of the various types of NMR data that can provide structural information, and then focus on the structure calculation methodology itself. We discuss and illustrate with tutorial examples both "classical" structure calculation and refinement approaches as well as more recently developed protocols for modeling biomolecular complexes.
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Affiliation(s)
- Gloria Fuentes
- Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, The Netherlands
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50
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Abstract
Two fundamentally different views of how proteins fold are now being debated. Do proteins fold through multiple unpredictable routes directed only by the energetically downhill nature of the folding landscape or do they fold through specific intermediates in a defined pathway that systematically puts predetermined pieces of the target native protein into place? It has now become possible to determine the structure of protein folding intermediates, evaluate their equilibrium and kinetic parameters, and establish their pathway relationships. Results obtained for many proteins have serendipitously revealed a new dimension of protein structure. Cooperative structural units of the native protein, called foldons, unfold and refold repeatedly even under native conditions. Much evidence obtained by hydrogen exchange and other methods now indicates that cooperative foldon units and not individual amino acids account for the unit steps in protein folding pathways. The formation of foldons and their ordered pathway assembly systematically puts native-like foldon building blocks into place, guided by a sequential stabilization mechanism in which prior native-like structure templates the formation of incoming foldons with complementary structure. Thus the same propensities and interactions that specify the final native state, encoded in the amino-acid sequence of every protein, determine the pathway for getting there. Experimental observations that have been interpreted differently, in terms of multiple independent pathways, appear to be due to chance misfolding errors that cause different population fractions to block at different pathway points, populate different pathway intermediates, and fold at different rates. This paper summarizes the experimental basis for these three determining principles and their consequences. Cooperative native-like foldon units and the sequential stabilization process together generate predetermined stepwise pathways. Optional misfolding errors are responsible for 3-state and heterogeneous kinetic folding.
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Affiliation(s)
- S Walter Englander
- The Johnson Research Foundation, Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia 19104-6059, USA.
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