1
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Schramm HM, Cabrera ER, Greer C, Clowers BH. A Modular Variable Temperature FT-IMS Instrument Optimized for Gas-Phase Ion Chemistry Applications. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2024. [PMID: 38994799 DOI: 10.1021/jasms.4c00183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/13/2024]
Abstract
The latest iteration of modular, open-source rolled ion mobility spectrometers was characterized and tailored for heated ion chemistry experiments. Because the nature of ion-neutral interactions is innately linked to the temperature of the drift cell, heated IMS experiments explicitly probe the fundamental characteristics of these collisions. While classic mobility experiments examine ions through inert buffer gases, doping the drift cell with reactive vapor enables desolvated chemical reactions to be studied. By using materials with minimal outgassing and ensuring the isolation of the drift tube from the surrounding ambient conditions, an open-source drift cell outfitted with heating components enables investigations of chemical reactions as a function of temperature. We show here that elevated temperatures facilitate an increase in deuterium incorporation and allow for hydrogen/deuterium exchanges otherwise unattainable under ambient conditions. While the initial fast exchanges get faster as temperature is increased, the slow rate which rises from the kinetic nonlinearity though to be attributed to ion-neutral clustering, remains constant with no change in mobility shifts. Additionally, we show the analytical merit of multiplexing mobility data by comparing the performance of traditional signal-averaging and FT-IMS modes.
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Affiliation(s)
- Haley M Schramm
- Department of Chemistry, Washington State University, Pullman, Washington 99163, United States
| | - Elvin R Cabrera
- Department of Chemistry, Washington State University, Pullman, Washington 99163, United States
| | - Cullen Greer
- Department of Chemistry, Washington State University, Pullman, Washington 99163, United States
| | - Brian H Clowers
- Department of Chemistry, Washington State University, Pullman, Washington 99163, United States
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2
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Webb IK. Perspective: The complex relationship between charge, mobility, and gas-phase protein structure. JOURNAL OF MASS SPECTROMETRY : JMS 2024; 59:e5013. [PMID: 38605450 DOI: 10.1002/jms.5013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Revised: 02/07/2024] [Accepted: 02/21/2024] [Indexed: 04/13/2024]
Abstract
Ion mobility spectrometry coupled to mass spectrometry (IMS/MS) is a widely used tool for biomolecular separations and structural elucidation. The application of IMS/MS has resulted in exciting developments in structural proteomics and genomics. This perspective gives a brief background of the field, addresses some of the important issues in making structural measurements, and introduces complementary techniques.
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Affiliation(s)
- Ian K Webb
- Department of Chemistry and Chemical Biology, Indiana University Purdue University Indianapolis, Indianapolis, Indiana, USA
- Center for Computational Biology and Bioinformatics, Indiana University School of Medicine, Indianapolis, Indiana, USA
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3
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Zviagin A, Boyarkin OV. Ion Spectroscopy Reveals Structural Difference for Proteins Microhydrated by Retention and Condensation of Water. J Phys Chem A 2024. [PMID: 38489273 DOI: 10.1021/acs.jpca.4c00263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/17/2024]
Abstract
Protein ubiquitin in its +7 charge state microhydrated by 5 and 10 water molecules has been interrogated in the gas phase by cold ion UV/IR spectroscopy. The complexes were formed either by condensing water onto the unfolded bare proteins in a temperature-controlled ion trap or by incomplete dehydration of the folded proteins. In the case of cryogenic condensation, the UV spectra of the complexes exhibit a resolved vibrational structure, which looks similar to the spectrum of bare unfolded ubiquitin. The spectra become, however, broad-band with no structure when complexes of the same size are produced by incomplete dehydration under soft conditions of electrospray ionization. We attribute this spectroscopic dissimilarity to the structural difference of the protein: condensing a few water molecules cannot refold the gas-phase structure of the bare ubiquitin, while the retained water preserves its solution-like folded motif through evaporative cooling. This assessment is firmly confirmed by IR spectroscopy, which reveals the presence of free NH and carboxylic OH stretching vibrations only in the complexes with condensed water.
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Affiliation(s)
- Andrei Zviagin
- SCI-SB-RB Group, ISIC, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Oleg V Boyarkin
- SCI-SB-RB Group, ISIC, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
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4
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Schramm HM, Tamadate T, Hogan CJ, Clowers BH. Evaluation of Hydrogen-Deuterium Exchange during Transient Vapor Binding of MeOD with Model Peptide Systems Angiotensin II and Bradykinin. J Phys Chem A 2023; 127:8849-8861. [PMID: 37827113 DOI: 10.1021/acs.jpca.3c04608] [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: 10/14/2023]
Abstract
The advancement of hybrid mass spectrometric tools as an indirect probe of molecular structure and dynamics relies heavily upon a clear understanding between gas-phase ion reactivity and ion structural characteristics. This work provides new insights into gas-phase ion-neutral reactions of the model peptides (i.e., angiotensin II and bradykinin) on a per-residue basis by integrating hydrogen/deuterium exchange, ion mobility, tandem mass spectrometry, selective vapor binding, and molecular dynamics simulations. By comparing fragmentation patterns with simulated probabilities of vapor uptake, a clear link between gas-phase hydrogen/deuterium exchange and the probabilities of localized vapor association is established. The observed molecular dynamics trends related to the sites and duration of vapor binding track closely with experimental observation. Additionally, the influence of additional charges and structural characteristics on exchange kinetics and ion-neutral cluster formation is examined. These data provide a foundation for the analysis of solvation dynamics of larger, native-like conformations of proteins in the gas phase.
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Affiliation(s)
- Haley M Schramm
- Department of Chemistry, Washington State University, Pullman, Washington 99163, United States
| | - Tomoya Tamadate
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Christopher J Hogan
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Brian H Clowers
- Department of Chemistry, Washington State University, Pullman, Washington 99163, United States
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5
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Wan J, Nytka M, Qian H, Lemr K, Tureček F. Do d(GCGAAGC) Cations Retain the Hairpin Structure in the Gas Phase? A Cyclic Ion Mobility Mass Spectrometry and Density Functional Theory Computational Study. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2023; 34:2323-2340. [PMID: 37696624 DOI: 10.1021/jasms.3c00228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/13/2023]
Abstract
d(GCGAAGC) is the smallest oligonucleotide with a well-defined hairpin structure in solution. We report a study of multiply protonated d(GCGAAGC) and its sequence-scrambled isomers, d(CGAAGCG), d(GCGAACG), and d(CGGAAGC), that were produced by electrospray ionization with the goal of investigating their gas-phase structures and dissociations. Cyclic ion mobility measurements revealed that dications of d(GCGAAGC) as well as the scrambled-sequence ions were mixtures of protomers and/or conformers that had collision cross sections (CCS) within a 439-481 Å2 range. Multiple ion conformers were obtained by electrospray under native conditions as well as from aqueous methanol. Arrival time distribution profiles were characteristic of individual isomeric heptanucleotides. Extensive Born-Oppenheimer molecular dynamics (BOMD) and density functional theory (DFT) calculations of d(GCGAAGC)2+ isomers indicated that hairpin structures were high-energy isomers of more compact distorted conformers. Protonation caused a break up of the C2···G6 pair that was associated with the formation of strong hydrogen bonds in zwitterionic phosphate anion-nucleobase cation motifs that predominated in low energy ions. Multiple components were also obtained for d(GCGAAGC)3+ trications under native and denaturing electrospray conditions. The calculated trication structures showed disruption of the G···C pairs in low energy zwitterions. A hairpin trication was calculated to be a high energy isomer. d(GCGAAGC)4+ tetracations were produced and separated by c-IMS as two major isomers. All low energy d(GCGAAGC)4+ ions obtained by DFT geometry optimizations were zwitterions in which all five purine bases were protonated, and the ion charge was balanced by a phosphate anion. Tetracations of the scrambled sequences were each formed as one dominant isomer. The CCS calculated with the MobCal-MPI method were found to closely match experimental values. Collision-induced dissociation (CID) spectra of multiply charged heptanucleotides showed nucleobase loss and backbone cleavages occurring chiefly at the terminal nucleosides. Electron-transfer-CID tandem mass spectra were used to investigate dissociations of different charge and spin states of charge-reduced heptanucleotide cation radicals.
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Affiliation(s)
- Jiahao Wan
- Department of Chemistry, University of Washington, Bagley Hall, Box 351700, Seattle, Washington 98195-1700, United States
| | - Marianna Nytka
- Department of Analytical Chemistry, Faculty of Science, Palacký University, 17. listopadu 12, 779 00 Olomouc, Czech Republic
- Institute of Microbiology of the Czech Academy of Sciences, Vídeňská 1083, 142 20 Prague, Czech Republic
| | - Haocheng Qian
- Department of Chemistry, University of Washington, Bagley Hall, Box 351700, Seattle, Washington 98195-1700, United States
| | - Karel Lemr
- Department of Analytical Chemistry, Faculty of Science, Palacký University, 17. listopadu 12, 779 00 Olomouc, Czech Republic
- Institute of Microbiology of the Czech Academy of Sciences, Vídeňská 1083, 142 20 Prague, Czech Republic
| | - František Tureček
- Department of Chemistry, University of Washington, Bagley Hall, Box 351700, Seattle, Washington 98195-1700, United States
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6
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Sharif D, Rahman M, Mahmud S, Sultana MN, Attanayake K, DeBastiani A, Foroushani SH, Li P, Valentine SJ. In-droplet hydrogen-deuterium exchange to examine protein/peptide solution conformer heterogeneity. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2023; 37:e9593. [PMID: 37430450 DOI: 10.1002/rcm.9593] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 04/25/2023] [Accepted: 05/22/2023] [Indexed: 07/12/2023]
Abstract
RATIONALE Many different structure analysis techniques are not capable of probing the heterogeneity of solution conformations. Here, we examine the ability of in-droplet hydrogen-deuterium exchange (HDX) to directly probe solution conformer heterogeneity of a protein with mass spectrometry (MS) detection. METHODS Two vibrating capillary vibrating sharp-edge spray ionization (cVSSI) devices have been arranged such that they generate microdroplet plumes of the analyte and D2 O reagent, which coalesce to form reaction droplets where HDX takes place in the solution environment. The native HDX-MS setup has been first explored for two model peptides that have distinct structural compositions in solution. The effectiveness of the multidevice cVSSI-HDX in illustrating structural details has been further exploited to investigate coexisting solution-phase conformations of the protein ubiquitin. RESULTS In-droplet HDX reveals decreased backbone exchange for a model peptide that has a greater helix-forming propensity. Differences in intrinsic rates of the alanine and serine residues may account for much of the observed protection. The data allow the first estimates of backbone exchange rates for peptides undergoing in-droplet HDX. That said, the approach may hold greater potential for investigating the tertiary structure and structural transitions of proteins. For ubiquitin protein, HDX reactivity differences suggest that multiple conformers are present in native solutions. The addition of methanol to buffered aqueous solutions of ubiquitin results in increased populations of solution conformers of higher reactivity. Data analysis suggests that partially folded conformers such as the A-state of ubiquitin increase with methanol content; the native state may be preserved to a limited degree even under stronger denaturation conditions. CONCLUSION The deuterium uptake after in-droplet HDX has been observed to correspond to some degree with peptide backbone hydrogen protection based on differences in intrinsic rates of exchange. The presence of coexisting protein solution structures under native and denaturing solution conditions has been distinguished by the isotopic distributions of deuterated ubiquitin ions.
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Affiliation(s)
- Daud Sharif
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia, USA
| | - Mohammad Rahman
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia, USA
| | - Sultan Mahmud
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia, USA
| | - Mst Nigar Sultana
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia, USA
| | - Kushani Attanayake
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia, USA
| | - Anthony DeBastiani
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia, USA
| | - Samira Hajian Foroushani
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia, USA
| | - Peng Li
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia, USA
| | - Stephen J Valentine
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia, USA
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7
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Smith RD. Large Individual Ion FTICR Measurements from the Mid-1990s Using Reactions for Charge Determination Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2023; 34:803-812. [PMID: 37021701 DOI: 10.1021/jasms.2c00329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
This article discusses from a personal and present-day perspective the first studies of large highly charged individual molecular ions that were conducted using electrospray ionization with Fourier transform ion cyclotron resonance MS in the mid-1990s. These studies are distinguished from Current Charge Detection Mass Spectrometry (CDMS) primarily by their use of individual ion charge state changes due to reactions for accurate charge determination. This work describes the key differences in technologies and methods with present CDMS and the likely implications of these differences. I comment on surprising individual ion behavior observed in some measurements involving increases in charge state, as well as their possible basis, and also briefly discuss the potential utility of the reaction-based mass measurement approach used in the context of what might more globally be referred to as "Charge Determination Mass Spectrometry".
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Affiliation(s)
- Richard D Smith
- Pacific Northwest National Laboratory Richland, Washington 99352 United States
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8
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Schramm HM, Tamadate T, Hogan CJ, Clowers BH. Ion-neutral clustering alters gas-phase hydrogen-deuterium exchange rates. Phys Chem Chem Phys 2023; 25:4959-4968. [PMID: 36722872 DOI: 10.1039/d2cp04388b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The rates and mechanisms of chemical reactions that occur at a phase boundary often differ considerably from chemical behavior in bulk solution, but remain difficult to quantify. Ion-neutral interactions are one such class of chemical reactions whose behavior during the nascent stages of solvation differs from bulk solution while occupying critical roles in aerosol formation, atmospheric chemistry, and gas-phase ion separations. Through a gas-phase ion separation technique utilizing a counter-current flow of deuterated vapor, we quantify the degree of hydrogen-deuterium exchange (HDX) and ion-neutral clustering on a series of model chemical systems (i.e. amino acids). By simultaneously quantifying the degree of vapor association and HDX, the effects of cluster formation on reaction kinetics are realized. These results imply that cluster formation cannot be ignored when modeling complex nucleation processes and biopolymer structural dynamics.
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Affiliation(s)
- Haley M Schramm
- Department of Chemistry, Washington State University, Pullman, WA 99163, USA.
| | - Tomoya Tamadate
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN 55455, USA
| | - Christopher J Hogan
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN 55455, USA
| | - Brian H Clowers
- Department of Chemistry, Washington State University, Pullman, WA 99163, USA.
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9
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Chaturvedi R, Webb IK. Multiplexed Conformationally Selective, Localized Gas-Phase Hydrogen Deuterium Exchange of Protein Ions Enabled by Transmission-Mode Electron Capture Dissociation. Anal Chem 2022; 94:8975-8982. [PMID: 35708487 DOI: 10.1021/acs.analchem.2c00942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In this article, we present an approach for conformationally multiplexed, localized hydrogen deuterium exchange (HDX) of gas-phase protein ions facilitated by ion mobility (IM) followed by electron capture dissociation (ECD). A quadrupole-IM-time of flight instrument previously modified to enable ECD in transmission mode (without ion trapping) immediately following a mobility separation was further modified to allow for deuterated ammonia (ND3) to be leaked in after m/z selection. Collisional activation was minimized to prevent deuterium scrambling from giving structurally irrelevant results. Gas-phase HDX with ECD fragmentation for exchange site localization was demonstrated with the extensively studied protein folding models ubiquitin and cytochrome c. Ubiquitin was ionized from conditions that stabilize the native state and conditions that stabilize the partially folded A-state. IM of deuterated ubiquitin 6+ ions allowed the separation of more compact conformers from more extended conformers. ECD of the separated subpopulations revealed that the more extended (later arriving) conformers had significant, localized differences in the amount of HDX observed. The 5+ charge state showed many regions with protection from HDX, and the 11+ charge state, ionized from conditions that stabilize the A-state, showed high levels of deuterium incorporation throughout most of the protein sequence. The 7+ ions of cytochrome c ionized from aqueous conditions showed greater HDX with unstructured regions of the protein relative to interior, structured regions, especially those involved in heme binding. With careful tuning and attention to deuterium scrambling, our approach holds promise for determining region-specific information on a conformer-selected basis for gas-phase protein structures, including localized characterizations of ligand, epitope, and protein-protein binding.
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Affiliation(s)
- Ritu Chaturvedi
- Department of Chemistry and Chemical Biology, Indiana University Purdue University Indianapolis, Indianapolis, Indiana 46202, United States
| | - Ian K Webb
- Department of Chemistry and Chemical Biology, Indiana University Purdue University Indianapolis, Indianapolis, Indiana 46202, United States.,Center for Computational Biology and Bioinformatics, Indiana University School of Medicine, Indianapolis, Indiana 46202, United States
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10
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Zviagin A, Kopysov V, Nagornova NS, Boyarkin OV. Tracking local and global structural changes in a protein by cold ion spectroscopy. Phys Chem Chem Phys 2022; 24:8158-8165. [PMID: 35332911 DOI: 10.1039/d2cp00217e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Characterization of native structures of proteins in the gas phase remains challenging due to the unpredictable conformational changes the molecules undergo during desolvation and ionization. We spectroscopically studied cryogenically cooled protonated protein ubiquitin and its microhydrated complexes prepared in the gas phase in a range of charge states under different ionization conditions. The UV spectra appear vibrationally resolved for the unfolded protein, but become redshifted and smooth for the native-like structures of ubiquitin. This spectroscopic change results from the H-bonding of the hydroxyl of Tyr to the amide group of Glu-51 in the compact structures; the minimum length of this bond was estimated to be ∼1.7 Å. IR spectroscopy reflects the global structural change by observing redshifts of free NH/OH-stretch vibrational transitions. Evaporative cooling of microhydrated complexes of ubiquitin keeps the protein chilly during ionization, enabling native-like conformers with up to eight protons to survive in the gas phase.
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Affiliation(s)
- Andrei Zviagin
- Laboratoire de Chimie Physique Moléculaire, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
| | - Vladimir Kopysov
- Laboratoire de Chimie Physique Moléculaire, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
| | - Natalia S Nagornova
- Laboratoire de Chimie Physique Moléculaire, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
| | - Oleg V Boyarkin
- Laboratoire de Chimie Physique Moléculaire, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
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11
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Raab SA, El-Baba TJ, Laganowsky A, Russell DH, Valentine SJ, Clemmer DE. Protons Are Fast and Smart; Proteins Are Slow and Dumb: On the Relationship of Electrospray Ionization Charge States and Conformations. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2021; 32:1553-1561. [PMID: 34151568 PMCID: PMC9003666 DOI: 10.1021/jasms.1c00100] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We present simple considerations of how differences in time scales of motions of protons, the lightest and fastest chemical moiety, and the much longer time scales associated with the dynamics of proteins, among the heaviest and slowest analytes, may allow many protein conformations from solution to be kinetically trapped during the process of electrospraying protein solutions into the gas phase. In solution, the quantum nature of protons leads them to change locations by tunneling, an instantaneous process; moreover, the Grotthuss mechanism suggests that these small particles can respond nearly instantaneously to the dynamic motions of proteins that occur on much longer time scales. A conformational change is accompanied by favorable or unfavorable variations in the free energy of the system, providing the impetus for solvent ↔ protein proton exchange. Thus, as thermal distributions of protein conformations interconvert, protonation states rapidly respond, as specific acidic and basic sites are exposed or protected. In the vacuum of the mass spectrometer, protons become immobilized in locations that are specific to the protein conformations from which they were incorporated. In this way, conformational states from solution are preserved upon electrospraying them into the gas phase. These ideas are consistent with the exquisite sensitivity of electrospray mass spectra to small changes of the local environment that alter protein structure in solution. We might remember this approximation for the protonation of proteins in solution with the colloquial expression-protons are fast and smart; proteins are slow and dumb.
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Affiliation(s)
- Shannon A Raab
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Tarick J El-Baba
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Arthur Laganowsky
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - David H Russell
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Stephen J Valentine
- Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - David E Clemmer
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
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12
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Uppal SS, Mookherjee A, Harkewicz R, Beasley SE, Bush MF, Guttman M. High-Precision, Gas-Phase Hydrogen/Deuterium-Exchange Kinetics by Mass Spectrometry Enabled by Exchange Standards. Anal Chem 2020; 92:7725-7732. [PMID: 32368904 DOI: 10.1021/acs.analchem.0c00749] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Mass spectrometry (MS) has become a primary tool for identifying and quantifying biological molecules. In combination with other orthogonal techniques, such as gas-phase hydrogen/deuterium exchange (gHDX), MS is also capable of probing the structure of ions. However, gHDX kinetics can depend strongly on many factors, including laboratory temperature, instrumental conditions, and instrument platform selection. These effects can lead to high variability with gHDX measurements, which has hindered the broader adoption of gHDX for structural MS. Here we introduce an approach for standardizing gHDX measurements using cosampled standards. Quantifying the exchange kinetics for analytes relative to the exchange kinetics of the standards results in greater accuracy and precision than the underlying absolute measurements. The standardization was found to be effective for several types of analytes including small molecules and intact proteins. A subset of analytes showed deviations in their standardized exchange profiles that are attributed to field heating and the concomitant conformational isomerization. Inclusion of helium during the gHDX process for collisional cooling helps mitigate such variations in exchange kinetics related to ion heating. We anticipate that the outcomes of this research will enable the broader use of gHDX in MS-based workflows for molecular identification and isomer differentiation.
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Affiliation(s)
- Sanjit S Uppal
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Abhigya Mookherjee
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Rick Harkewicz
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Sarah E Beasley
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Matthew F Bush
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Miklos Guttman
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington 98195, United States
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13
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Arndt JR, Chaibva M, Beasley M, Karanji AK, Kondalaji SG, Khakinejad M, Sarver O, Legleiter J, Valentine SJ. Nucleation Inhibition of Huntingtin Protein (htt) by Polyproline PPII Helices: A Potential Interaction with the N-Terminal α-Helical Region of Htt. Biochemistry 2020; 59:436-449. [PMID: 31814404 PMCID: PMC7344267 DOI: 10.1021/acs.biochem.9b00689] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Huntington's disease is a genetic neurodegenerative disorder characterized by the formation of amyloid fibrils of the huntingtin protein (htt). The 17-residue N-terminal region of htt (Nt17) has been implicated in the formation of early phase oligomeric species, which may be neurotoxic. Because tertiary interactions with a downstream (C-terminal) polyproline (polyP) region of htt may disrupt the formation of oligomers, which are precursors to fibrillar species, the effect of co-incubation of a region of htt with a 10-residue polyP peptide on oligomerization and fibrillization has been examined by atomic force microscopy. From multiple, time-course experiments, morphological changes in oligomeric species are observed for the protein/peptide mixture and compared with the protein alone. Additionally, an overall decrease in fibril formation is observed for the heterogeneous mixture. To consider potential sites of interaction between the Nt17 region and polyP, mixtures containing Nt17 and polyP peptides have been examined by ion mobility spectrometry and gas-phase hydrogen-deuterium exchange coupled with mass spectrometry. These data combined with molecular dynamics simulations suggest that the C-terminal region of Nt17 may be a primary point of contact. One interpretation of the results is that polyP may possibly regulate Nt17 by inducing a random coil region in the C-terminal portion of Nt17, thus decreasing the propensity to form the reactive amphipathic α-helix. A separate interpretation is that the residues important for helix-helix interactions are blocked by polyP association.
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Affiliation(s)
- James R Arndt
- C. Eugene Bennett Department of Chemistry, West Virginia University, 100 Prospect Street, Morgantown, West Virginia 26506, United States
| | - Maxmore Chaibva
- C. Eugene Bennett Department of Chemistry, West Virginia University, 100 Prospect Street, Morgantown, West Virginia 26506, United States
| | - Maryssa Beasley
- C. Eugene Bennett Department of Chemistry, West Virginia University, 100 Prospect Street, Morgantown, West Virginia 26506, United States
| | - Ahmad Kiani Karanji
- C. Eugene Bennett Department of Chemistry, West Virginia University, 100 Prospect Street, Morgantown, West Virginia 26506, United States
| | - Samaneh Ghassabi Kondalaji
- C. Eugene Bennett Department of Chemistry, West Virginia University, 100 Prospect Street, Morgantown, West Virginia 26506, United States
| | - Mahdiar Khakinejad
- C. Eugene Bennett Department of Chemistry, West Virginia University, 100 Prospect Street, Morgantown, West Virginia 26506, United States
| | - Olivia Sarver
- C. Eugene Bennett Department of Chemistry, West Virginia University, 100 Prospect Street, Morgantown, West Virginia 26506, United States
| | - Justin Legleiter
- C. Eugene Bennett Department of Chemistry, West Virginia University, 100 Prospect Street, Morgantown, West Virginia 26506, United States
- WV Nano Safe Iniative, West Virginia University, Morgantown, West Virginia 26506, United States
- The Center for Neuroscience, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Stephen J Valentine
- C. Eugene Bennett Department of Chemistry, West Virginia University, 100 Prospect Street, Morgantown, West Virginia 26506, United States
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14
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Breitgoff FD, Keller K, Qi M, Klose D, Yulikov M, Godt A, Jeschke G. UWB DEER and RIDME distance measurements in Cu(II)-Cu(II) spin pairs. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2019; 308:106560. [PMID: 31377151 DOI: 10.1016/j.jmr.2019.07.047] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 07/12/2019] [Accepted: 07/15/2019] [Indexed: 06/10/2023]
Abstract
Distance determination by Electron Paramagnetic Resonance (EPR) based on measurements of the dipolar coupling are technically challenging for electron spin systems with broad spectra due to comparatively narrow microwave pulse excitation bandwidths. With Na4[{CuII(PyMTA)}-(stiff spacer)-{CuII(PyMTA)}] as a model compound, we compared DEER and RIDME measurements and investigated the use of frequency-swept pulses. We found very large improvements in sensitivity when substituting the monochromatic pump pulse by a frequency-swept one in DEER experiments with monochromatic observer pulses. This effect was especially strong in X band, where nearly the whole spectrum can be included in the experiment. The RIDME experiment is characterised by a trade-off in signal intensity and modulation depth. Optimal parameters are further influenced by varying steepness of the background decay. A simple 2-point optimization experiment was found to serve as good estimate to identify the mixing time of highest sensitivity. Using frequency-swept pulses in the observer sequences resulted in lower SNR in both the RIDME and the DEER experiment. Orientation selectivity was found to vary in both experiments with the detection position as well as with the settings of the pump pulse in DEER. In RIDME, orientation selection by relaxation anisotropy of the inverted spin appeared to be negligible as form factors remain relatively constant with varying mixing time. This reduces the overall observed orientation selection to the one given by the detection position. Field-averaged data from RIDME and DEER with a shaped pump pulse resulted in the same dipolar spectrum. We found that both methods have their advantages and disadvantages for given instrumental limitations and sample properties. Thus the choice of method depends on the situation at hand and we discuss which parameters should be considered for optimization.
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Affiliation(s)
- Frauke D Breitgoff
- ETH Zürich, Lab. Phys. Chem., Vladimir-Prelog-Weg 2, 8063 Zürich 3 Switzerland.
| | - Katharina Keller
- ETH Zürich, Lab. Phys. Chem., Vladimir-Prelog-Weg 2, 8063 Zürich 3 Switzerland.
| | - Mian Qi
- Faculty of Chemistry and Center for Molecular Materials (CM(2)), Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany
| | - Daniel Klose
- ETH Zürich, Lab. Phys. Chem., Vladimir-Prelog-Weg 2, 8063 Zürich 3 Switzerland
| | - Maxim Yulikov
- ETH Zürich, Lab. Phys. Chem., Vladimir-Prelog-Weg 2, 8063 Zürich 3 Switzerland
| | - Adelheid Godt
- Faculty of Chemistry and Center for Molecular Materials (CM(2)), Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany.
| | - Gunnar Jeschke
- ETH Zürich, Lab. Phys. Chem., Vladimir-Prelog-Weg 2, 8063 Zürich 3 Switzerland
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15
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Conant CR, Fuller DR, Zhang Z, Woodall DW, Russell DH, Clemmer DE. Substance P in the Gas Phase: Conformational Changes and Dissociations Induced by Collisional Activation in a Drift Tube. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2019; 30:932-945. [PMID: 30980379 PMCID: PMC6865269 DOI: 10.1007/s13361-019-02160-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 02/15/2019] [Accepted: 02/15/2019] [Indexed: 05/02/2023]
Abstract
The work presented below is related to our companion paper in this issue, entitled: Substance P in solution: trans-to-cis configurational changes of penultimate prolines initiate non-enzymatic peptide bond cleavages. Two-dimensional ion mobility spectrometry (IMS-IMS) and mass spectrometry techniques are used to investigate structural transitions for [M+3H]3+ ions of substance P (subP) upon collisional activation (CA) in the gas phase. In this approach, different conformations of ions having a specified mobility are selected after an initial IMS separation, collisionally activated to produce new conformers, and these product structures are separated again using a second IMS region. In this way, it is possible to follow folding and unfolding transitions of different conformations. The analysis shows evidence for five conformations. Unlike other systems, every transition is irreversible. Studies as a function of activation voltage are used to discern pathways of structural changes prior to reaching the energy required for dissociation. Thresholds associated with the onsets of transitions are calibrated to obtain estimates of the energetic barriers between different structures and semi-quantitative potential energy diagrams are presented. Overall, barriers associated with structural transitions of [subP+3H]3+ in the absence of solvent are on the order of ~ 40 kJ mol-1, substantially lower than the ~ 90 kJ mol-1 required for some similar structural transitions in solutions of ethanol. Comparisons of the transition energies in the gas phase with thermochemistry for similar transitions in solution provide clues about why reverse transitions are prohibited. Graphical Abstract.
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Affiliation(s)
- Christopher R Conant
- Department of Chemistry, Indiana University, 800 Kirkwood Avenue, Bloomington, IN, 47401, USA
| | - Daniel R Fuller
- Department of Chemistry, Indiana University, 800 Kirkwood Avenue, Bloomington, IN, 47401, USA
| | - Zhichao Zhang
- Department of Chemistry, Indiana University, 800 Kirkwood Avenue, Bloomington, IN, 47401, USA
| | - Daniel W Woodall
- Department of Chemistry, Indiana University, 800 Kirkwood Avenue, Bloomington, IN, 47401, USA
| | - David H Russell
- Department of Chemistry, Texas A&M University, College Station, TX, 77843, USA
| | - David E Clemmer
- Department of Chemistry, Indiana University, 800 Kirkwood Avenue, Bloomington, IN, 47401, USA.
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16
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Kelly K, Bell S, Maleki H, Valentine S. Synthetic Small Molecule Characterization and Isomer Discrimination Using Gas-Phase Hydrogen-Deuterium Exchange IMS-MS. Anal Chem 2019; 91:6259-6265. [PMID: 30999746 DOI: 10.1021/acs.analchem.9b00979] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Ion mobility spectrometry-mass spectrometry (IMS-MS) combined with gas-phase hydrogen-deuterium exchange has been used to characterize novel psychoactive substances (NPSs) which are small synthetic compounds designed to mimic the effects of other illicit substances. Here, NPSs containing labile heteroatom hydrogens were evaluated for HDX reactivity in the presence of either deuterated water (D2O) or ammonia (ND3) within the drift tube. An initial evaluation of exchange propensity was performed for six NPSs. Five compounds exchanged in the presence of ND3 while only one NPS (benzyl piperazine) exchanged with D2O. The exchange mechanism of D2O requires stabilization with a nearby charged site; the diamine ring of benzyl piperazine provided this charge site at a fixed length. Three disubstituted benzene isomers ( o-, m-, and p-fluorophenyl piperazine) containing the diamine ring structure and a fluorine atom were subsequently analyzed. Having identical isotopic composition and nearly identical drift time distributions, these isomers could not be distinguished by IMS-MS alone. However, upon undergoing HDX in the drift tube, a t test of means (α = 0.05) showed that discrimination was possible if the exchange data from both reagent gases were included. Molecular dynamics simulations show that the proximity of the fluorine to the diamine ring hinders the dihedral angle rotation between the benzene and the diamine ring; this may partially account for the observed exchange differences.
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17
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Czar MF, Marchand A, Zenobi R. A Modified Traveling Wave Ion Mobility Mass Spectrometer as a Versatile Platform for Gas-Phase Ion-Molecule Reactions. Anal Chem 2019; 91:6624-6631. [PMID: 31008583 DOI: 10.1021/acs.analchem.9b00541] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Taken individually, chemical labeling and mass spectrometry are two well-established tools for the structural characterization of biomolecular complexes. A way to combine their respective advantages is to perform gas-phase ion-molecule reactions (IMRs) inside the mass spectrometer. This is, however, not so well developed because of the limited range of usable chemicals and the lack of commercially available IMR devices. Here, we modified a traveling wave ion mobility mass spectrometer to enable IMRs in the trapping region of the instrument. Only one minor hardware modification is needed to allow vapors of a variety of liquid reagents to be leaked into the trap traveling wave ion guide of the instrument. A diverse set of IMRs can then readily be performed without any loss in instrument performance. We demonstrate the advantages of implementing IMR capabilities in general, and to this quadrupole-ion mobility-time-of-flight (Q-IM-TOF) mass spectrometer in particular, by exploiting the full functionality of the instrument, including mass selection, ion mobility separation, and post-mobility fragmentation. The potential to carry out gas-phase IMR kinetics experiments is also illustrated. We demonstrate the versatility of the setup using gas-phase IMRs of established utility for biological mass spectrometry, including hydrogen-deuterium exchange, ion-molecule proton transfer reactions, and covalent modification of DNA anions using trimethylsilyl chloride.
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Affiliation(s)
- Martin F Czar
- Laboratory of Organic Chemistry, Department of Chemistry and Applied Biosciences , ETH Zurich , Zurich 8093 , Switzerland
| | - Adrien Marchand
- Laboratory of Organic Chemistry, Department of Chemistry and Applied Biosciences , ETH Zurich , Zurich 8093 , Switzerland
| | - Renato Zenobi
- Laboratory of Organic Chemistry, Department of Chemistry and Applied Biosciences , ETH Zurich , Zurich 8093 , Switzerland
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18
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Mistarz UH, Chandler SA, Brown JM, Benesch JLP, Rand KD. Probing the Dissociation of Protein Complexes by Means of Gas-Phase H/D Exchange Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2019; 30:45-57. [PMID: 30460642 DOI: 10.1007/s13361-018-2064-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 08/29/2018] [Accepted: 08/30/2018] [Indexed: 05/16/2023]
Abstract
Gas-phase hydrogen/deuterium exchange measured by mass spectrometry (gas-phase HDX-MS) is a fast method to probe the conformation of protein ions. The use of gas-phase HDX-MS to investigate the structure and interactions of protein complexes is however mostly unharnessed. Ionizing proteins under conditions that maximize preservation of their native structure (native MS) enables the study of solution-like conformation for milliseconds after electrospray ionization (ESI), which enables the use of ND3-gas inside the mass spectrometer to rapidly deuterate heteroatom-bound non-amide hydrogens. Here, we explored the utility of gas-phase HDX-MS to examine protein-protein complexes and inform on their binding surface and the structural consequences of gas-phase dissociation. Protein complexes ranging from 24 kDa dimers to 395 kDa 24mers were analyzed by gas-phase HDX-MS with subsequent collision-induced dissociation (CID). The number of exchangeable sites involved in complex formation could, therefore, be estimated. For instance, dimers of cytochrome c or α-lactalbumin incorporated less deuterium/subunit than their unbound monomer counterparts, providing a measure of the number of heteroatom-bound side-chain hydrogens involved in complex formation. We furthermore studied if asymmetric charge-partitioning upon dissociation of protein complexes caused intermolecular H/D migration. In larger multimeric protein complexes, the dissociated monomer showed a significant increase in deuterium. This indicates that intermolecular H/D migration occurs as part of the asymmetric partitioning of charge during CID. We discuss several models that may explain this increase deuterium content and find that a model where only deuterium involved in migrating charge can account for most of the deuterium enrichment observed on the ejected monomer. In summary, the deuterium content of the ejected subunit can be used to estimate that of the intact complex with deviations observed for large complexes accounted for by charge migration. Graphical abstract ᅟ.
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Affiliation(s)
- Ulrik H Mistarz
- Protein Analysis Group, Department of Pharmacy, University of Copenhagen, Universitetsparken 2, 2100, Copenhagen, Denmark
| | - Shane A Chandler
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QZ, UK
| | - Jeffery M Brown
- Waters Corporation, Stamford Avenue, Altrincham Road, Wilmslow, SK9 4AX, UK
| | - Justin L P Benesch
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QZ, UK.
| | - Kasper D Rand
- Protein Analysis Group, Department of Pharmacy, University of Copenhagen, Universitetsparken 2, 2100, Copenhagen, Denmark.
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19
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Karanji AK, Khakinejad M, Kondalaji SG, Majuta SN, Attanayake K, Valentine SJ. Comparison of Peptide Ion Conformers Arising from Non-Helical and Helical Peptides Using Ion Mobility Spectrometry and Gas-Phase Hydrogen/Deuterium Exchange. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2018; 29:2402-2412. [PMID: 30324261 PMCID: PMC6553874 DOI: 10.1007/s13361-018-2053-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 07/17/2018] [Accepted: 08/03/2018] [Indexed: 05/06/2023]
Abstract
The dominant gas-phase conformer of [M+3H]3+ ions of the model peptide acetyl-PSSSSKSSSSKSSSSKSSSSK has been examined with ion mobility spectrometry (IMS), gas-phase hydrogen deuterium exchange (HDX), and mass spectrometry (MS) techniques. The [M+3H]3+ peptide ions are observed predominantly as a relatively compact conformer type. Upon subjecting these ions to electron transfer dissociation (ETD), the level of protection for each amino acid residue in the peptide sequence is assessed. The overall per-residue deuterium uptake is observed to be relatively more efficient for the neutral residues than for the model peptide acetyl-PAAAAKAAAAKAAAAKAAAAK. In comparison, the N-terminal and C-terminal regions of the serine peptide show greater relative protection compared with interior residues. Molecular dynamics (MD) simulations have been used to generate candidate structures for collision cross section and HDX reactivity matching. Hydrogen accessibility scoring (HAS) for select structural candidates from MD simulations has been used to suggest conformer types that could contribute to the observed HDX patterns. The results are discussed with respect to recent studies employing extensive MD simulations of gas-phase structure establishment of a peptide system. Graphical Abstract ᅟ.
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Affiliation(s)
- Ahmad Kiani Karanji
- Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA
| | - Mahdiar Khakinejad
- Department of Biophysics, Johns Hopkins University, Baltimore, MD, 21218, USA
| | | | - Sandra N Majuta
- Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA
| | - Kushani Attanayake
- Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA
| | - Stephen J Valentine
- Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA.
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20
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Kostyukevich Y, Acter T, Zherebker A, Ahmed A, Kim S, Nikolaev E. Hydrogen/deuterium exchange in mass spectrometry. MASS SPECTROMETRY REVIEWS 2018; 37:811-853. [PMID: 29603316 DOI: 10.1002/mas.21565] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 02/22/2018] [Accepted: 03/08/2018] [Indexed: 05/22/2023]
Abstract
The isotopic exchange approach is in use since the first observation of such reactions in 1933 by Lewis. This approach allows the investigation of the pathways of chemical and biochemical reactions, determination of structure, composition, and conformation of molecules. Mass spectrometry has now become one of the most important analytical tools for the monitoring of the isotopic exchange reactions. Investigation of conformational dynamics of proteins, quantitative measurements, obtaining chemical, and structural information about individual compounds of the complex natural mixtures are mainly based on the use of isotope exchange in combination with high resolution mass spectrometry. The most important reaction is the Hydrogen/Deuterium exchange, which is mainly performed in the solution. Recently we have developed the approach allowing performing of the Hydrogen/Deuterium reaction on-line directly in the ionization source under atmospheric pressure. Such approach simplifies the sample preparation and can accelerate the exchange reaction so that certain hydrogens that are considered as non-labile will also participate in the exchange. The use of in-ionization source H/D exchange in modern mass spectrometry for structural elucidation of molecules serves as the basic theme in this review. We will focus on the mechanisms of the isotopic exchange reactions and on the application of in-ESI, in-APCI, and in-APPI source Hydrogen/Deuterium exchange for the investigation of petroleum, natural organic matter, oligosaccharides, and proteins including protein-protein complexes. The simple scenario for adaptation of H/D exchange reactions into mass spectrometric method is also highlighted along with a couple of examples collected from previous studies.
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Affiliation(s)
- Yury Kostyukevich
- Skolkovo Institute of Science and Technology, Skolkovo, Russian Federation
- Institute for Energy Problems of Chemical Physics Russian Academy of Sciences, Moscow, Russia
- Moscow Institute of Physics and Technology, Dolgoprudnyi, Moscow Region, Russia
| | - Thamina Acter
- Department of Chemistry, Kyungpook National University, Daegu, Republic of Korea
| | - Alexander Zherebker
- Skolkovo Institute of Science and Technology, Skolkovo, Russian Federation
- Institute for Energy Problems of Chemical Physics Russian Academy of Sciences, Moscow, Russia
| | - Arif Ahmed
- Department of Chemistry, Kyungpook National University, Daegu, Republic of Korea
| | - Sunghwan Kim
- Department of Chemistry, Kyungpook National University, Daegu, Republic of Korea
- Green Nano Center, Kyungpook National University, Daegu, Republic of Korea
| | - Eugene Nikolaev
- Skolkovo Institute of Science and Technology, Skolkovo, Russian Federation
- Institute for Energy Problems of Chemical Physics Russian Academy of Sciences, Moscow, Russia
- Moscow Institute of Physics and Technology, Dolgoprudnyi, Moscow Region, Russia
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21
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Oganesyan I, Lento C, Wilson DJ. Contemporary hydrogen deuterium exchange mass spectrometry. Methods 2018; 144:27-42. [DOI: 10.1016/j.ymeth.2018.04.023] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 04/16/2018] [Accepted: 04/21/2018] [Indexed: 02/07/2023] Open
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22
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Mistarz UH, Rand KD. Installation, validation, and application examples of two instrumental setups for gas-phase HDX-MS analysis of peptides and proteins. Methods 2018; 144:113-124. [PMID: 29753788 DOI: 10.1016/j.ymeth.2018.05.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 04/17/2018] [Accepted: 05/04/2018] [Indexed: 01/15/2023] Open
Abstract
Gas-phase hydrogen/deuterium exchange measured by mass spectrometry in a millisecond timeframe after ESI (gas-phase HDX-MS) is a fast and sensitive, yet unharnessed method to analyze the primary- and higher-order structure, intramolecular and intermolecular interactions, surface properties, and charge location of peptides and proteins. During a gas-phase HDX-MS experiment, heteroatom-bound non-amide hydrogens are made to exchange with deuterium during a millisecond timespan after electrospray ionization (ESI) by reaction with the highly basic reagent ND3, enabling conformational analysis of protein states that are pertinent to the native solution-phase. Here, we describe two different instrumental approaches to enable gas-phase HDX-MS for analysis of peptides and proteins on high-resolution Q-TOF mass spectrometers. We include a description of the procedure and equipment required for successful installation as well as suggested procedures for testing, validation, and troubleshooting of a gas-phase HDX-MS setup. In the two described approaches, gas-phase HDX-MS are performed either immediately after ESI in the cone exit region by leading N2-gas over a deuterated ND3/D2O solution, or by leading purified ND3-gas into different traveling wave ion guides (TWIG) of the mass spectrometer. We envision that a detailed description of the two gas-phase HDX-MS setups and their practical implementation and validation can pave the way for gas-phase HDX-MS to become a more routinely used MS technique for structural analysis of peptides and proteins.
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Affiliation(s)
- Ulrik H Mistarz
- Department of Pharmacy, University of Copenhagen, Copenhagen, Denmark
| | - Kasper D Rand
- Department of Pharmacy, University of Copenhagen, Copenhagen, Denmark.
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23
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Maleki H, Karanji AK, Majuta S, Maurer MM, Valentine SJ. Ion Mobility Spectrometry-Mass Spectrometry Coupled with Gas-Phase Hydrogen/Deuterium Exchange for Metabolomics Analyses. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2018; 29:230-241. [PMID: 28956290 PMCID: PMC5942887 DOI: 10.1007/s13361-017-1798-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 08/22/2017] [Accepted: 08/26/2017] [Indexed: 05/11/2023]
Abstract
Ion mobility spectrometry-mass spectrometry (IMS-MS) in combination with gas-phase hydrogen/deuterium exchange (HDX) and collision-induced dissociation (CID) is evaluated as an analytical method for small-molecule standard and mixture characterization. Experiments show that compound ions exhibit unique HDX reactivities that can be used to distinguish different species. Additionally, it is shown that gas-phase HDX kinetics can be exploited to provide even further distinguishing capabilities by using different partial pressures of reagent gas. The relative HDX reactivity of a wide variety of molecules is discussed in light of the various molecular structures. Additionally, hydrogen accessibility scoring (HAS) and HDX kinetics modeling of candidate (in silico) ion structures is utilized to estimate the relative ion conformer populations giving rise to specific HDX behavior. These data interpretation methods are discussed with a focus on developing predictive tools for HDX behavior. Finally, an example is provided in which ion mobility information is supplemented with HDX reactivity data to aid identification efforts of compounds in a metabolite extract. Graphical Abstract ᅟ.
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Affiliation(s)
- Hossein Maleki
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA
| | - Ahmad K Karanji
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA
| | - Sandra Majuta
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA
| | - Megan M Maurer
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA
| | - Stephen J Valentine
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA.
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24
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Yang Y, Liao G, Kong X. Charge-state Resolved Infrared Multiple Photon Dissociation (IRMPD) Spectroscopy of Ubiquitin Ions in the Gas Phase. Sci Rep 2017; 7:16592. [PMID: 29185478 PMCID: PMC5707388 DOI: 10.1038/s41598-017-16831-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 11/16/2017] [Indexed: 11/25/2022] Open
Abstract
In this study, we obtained for the first time the direct infrared multiple photon dissociation (IRMPD) spectra of ubiquitin ions in the range 2700-3750 cm-1. Ubiquitin ions with different charge states showed absorption in the two regions of 2940-3000 cm-1 and 3280-3400 cm-1. The increase of the charge state of ubiquitin ions broadened the absorption peak on the high-frequency side in the second region, indicating some hydrogen bonds were weakened due to Coulomb interaction. It is also found that the relative intensity of the absorption peak in the first region compared to the absorption peak in the second region increased with increasing charge state, making the IRMPD spectra charge-state resolved. Although it is usually reasonable to suggest the origin of the absorption in the range 2940-3000 cm-1 as the C-H bond stretching modes, the results show significantly reduced absorption after the deuteration of all labile hydrogen atoms. A possible explanation for this is that the coupling coefficients between the C-H vibrational mode and other selective modes decreased greatly after the deuteration, reducing the rate of energy redistribution and probability of consecutive IR absorption.
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Affiliation(s)
- Yijie Yang
- State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin, 300071, China
| | - Guanhua Liao
- State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin, 300071, China
| | - Xianglei Kong
- State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin, 300071, China.
- Collaborative Innovation Center of Chemical Science and Engineering, Nankai University, Tianjin, 300071, China.
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25
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Molano-Arevalo JC, Dit Fouque KJ, Pham K, Miksovska J, Ridgeway ME, Park MA, Fernandez-Lima F. Characterization of Intramolecular Interactions of Cytochrome c Using Hydrogen-Deuterium Exchange-Trapped Ion Mobility Spectrometry-Mass Spectrometry and Molecular Dynamics. Anal Chem 2017; 89:8757-8765. [PMID: 28742962 PMCID: PMC5653375 DOI: 10.1021/acs.analchem.7b00844] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Globular proteins, such as cytochrome c (cyt c), display an organized native conformation, maintained by a hydrogen bond interaction network. In the present work, the structural interrogation of kinetically trapped intermediates of cyt c was performed by correlating the ion-neutral collision cross section (CCS) and charge state with the starting solution conditions and time after desolvation using collision induced activation (CIA), time-resolved hydrogen/deuterium back exchange (HDX) and trapped ion mobility spectrometry-mass spectrometry (TIMS-MS). The high ion mobility resolving power of the TIMS analyzer allowed the identification of new ion mobility bands, yielding a total of 63 mobility bands over the +6 to +21 charge states and 20 mobility bands over the -5 to -10 charge states. Mobility selected HDX rates showed that for the same charge state, conformers with larger CCS present faster HDX rates in both positive and negative ion mode, suggesting that the charge sites and neighboring exchange sites on the accessible surface area define the exchange rate regardless of the charge state. Complementary molecular dynamic simulations permitted the generation of candidate structures and a mechanistic model of the folding transitions from native (N) to molten globule (MG) to kinetic intermediates (U) pathways. Our results suggest that cyt c major structural unfolding is associated with the distancing of the N- and C-terminal helices and subsequent solvent exposure of the hydrophobic, heme-containing cavity.
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Affiliation(s)
| | - Kevin Jeanne Dit Fouque
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, USA
| | - Khoa Pham
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, USA
| | - Jaroslava Miksovska
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, USA
- Biomolecular Sciences Institute, Florida International University, Miami, FL 33199
| | | | - Melvin A. Park
- Bruker Daltonics, Inc., Billerica, Massachusetts, 01821, USA
| | - Francisco Fernandez-Lima
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, USA
- Biomolecular Sciences Institute, Florida International University, Miami, FL 33199
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26
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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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27
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Maleki H, Maurer MM, Ronaghi N, Valentine SJ. Ion Mobility, Hydrogen/Deuterium Exchange, and Isotope Scrambling: Tools to Aid Compound Identification in ‘Omics Mixtures. Anal Chem 2017; 89:6399-6407. [PMID: 28505408 DOI: 10.1021/acs.analchem.7b00075] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Hossein Maleki
- Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Megan M. Maurer
- Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Nima Ronaghi
- Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Stephen J. Valentine
- Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
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28
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Khakinejad M, Ghassabi Kondalaji S, Tafreshian A, Valentine SJ. Comprehensive Gas-Phase Peptide Ion Structure Studies Using Ion Mobility Techniques: Part 2. Gas-Phase Hydrogen/Deuterium Exchange for Ion Population Estimation. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2017; 28:960-970. [PMID: 28315238 PMCID: PMC5656063 DOI: 10.1007/s13361-017-1641-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 02/23/2017] [Accepted: 02/25/2017] [Indexed: 05/09/2023]
Abstract
Gas-phase hydrogen/deuterium exchange (HDX) using D2O reagent and collision cross-section (CCS) measurements are utilized to monitor the ion conformers of the model peptide acetyl-PAAAAKAAAAKAAAAKAAAAK. The measurements are carried out on a home-built ion mobility instrument coupled to a linear ion trap mass spectrometer containing electron transfer dissociation (ETD) capabilities. ETD is utilized to obtain per-residue deuterium uptake data for select ion conformers, and a new algorithm is presented for interpreting the HDX data. Using molecular dynamics (MD) production data and a hydrogen accessibility scoring (HAS)-number of effective collisions (NEC) model, hypothetical HDX behavior is attributed to various in-silico candidate (CCS match) structures. The HAS-NEC model is applied to all candidate structures, and non-negative linear regression is employed to determine structure contributions resulting in the best match to deuterium uptake. The accuracy of the HAS-NEC model is tested with the comparison of predicted and experimental isotopic envelopes for several of the observed c-ions. It is proposed that gas-phase HDX can be utilized effectively as a second criterion (after CCS matching) for filtering suitable MD candidate structures. In this study, the second step of structure elucidation, 13 nominal structures were selected (from a pool of 300 candidate structures) and each with a population contribution proposed for these ions. Graphical Abstract ᅟ.
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Affiliation(s)
- Mahdiar Khakinejad
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA
| | | | - Amirmahdi Tafreshian
- Department of Statistics, West Virginia University, P.O. Box 6330, Morgantown, WV, 26506, USA
| | - Stephen J Valentine
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA.
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29
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Uppal SS, Beasley SE, Scian M, Guttman M. Gas-Phase Hydrogen/Deuterium Exchange for Distinguishing Isomeric Carbohydrate Ions. Anal Chem 2017; 89:4737-4742. [PMID: 28304155 DOI: 10.1021/acs.analchem.7b00683] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The structural diversity of carbohydrates presents a major challenge for glycobiology and the analysis of glycoconjugates. Mass spectrometry has become a primary tool for glycan analysis thanks to its speed and sensitivity, but the information content regarding the glycan structure of protonated glycoconjugates is hindered by the inability to differentiate linkage and stereoisomers. Here, we examine a variety of protonated carbohydrate structures by gas-phase hydrogen/deuterium exchange (HDX) to discover that the exchange rates are distinct for isomeric carbohydrates with even subtle structural differences. By incorporating an internal exchange standard, HDX could effectively distinguish all linkage and stereoisomers that were examined and presents a mass spectrometry-based approach for glycan structural analysis with immense potential.
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Affiliation(s)
- Sanjit S Uppal
- Department of Medicinal Chemistry, University of Washington , Seattle, Washington 98195, United States
| | - Sarah E Beasley
- Department of Medicinal Chemistry, University of Washington , Seattle, Washington 98195, United States
| | - Michele Scian
- Department of Medicinal Chemistry, University of Washington , Seattle, Washington 98195, United States
| | - Miklos Guttman
- Department of Medicinal Chemistry, University of Washington , Seattle, Washington 98195, United States
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30
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Straus RN, Jockusch RA. Probing the Gaseous Structure of a β-Hairpin Peptide with H/D Exchange and Electron Capture Dissociation. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2017; 28:358-369. [PMID: 27943124 DOI: 10.1007/s13361-016-1528-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 10/05/2016] [Accepted: 10/10/2016] [Indexed: 06/06/2023]
Abstract
An improved understanding of the extent to which native protein structure is retained upon transfer to the gas phase promises to enhance biological mass spectrometry, potentially streamlining workflows and providing fundamental insights into hydration effects. Here, we investigate the gaseous conformation of a model β-hairpin peptide using gas-phase hydrogen-deuterium (H/D) exchange with subsequent electron capture dissociation (ECD). Global gas-phase H/D exchange levels, and residue-specific exchange levels derived from ECD data, are compared among the wild type 16-residue peptide GB1p and several variants. High protection from H/D exchange observed for GB1p, but not for a truncated version, is consistent with the retention of secondary structure of GB1p in the gas phase or its refolding into some other compact structure. Four alanine mutants that destabilize the hairpin in solution show levels of protection similar to that of GB1p, suggesting collapse or (re)folding of these peptides upon transfer to the gas phase. These results offer a starting point from which to understand how a key secondary structural element, the β-hairpin, is affected by transfer to the gas phase. This work also demonstrates the utility of a much-needed addition to the tool set that is currently available for the investigation of the gaseous conformation of biomolecules, which can be employed in the future to better characterize gaseous proteins and protein complexes. Graphical Abstract ᅟ.
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Affiliation(s)
- Rita N Straus
- Department of Chemistry, University of Toronto, Toronto, ON, M5S 3H6, Canada
| | - Rebecca A Jockusch
- Department of Chemistry, University of Toronto, Toronto, ON, M5S 3H6, Canada.
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31
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Lössl P, van de Waterbeemd M, Heck AJ. The diverse and expanding role of mass spectrometry in structural and molecular biology. EMBO J 2016; 35:2634-2657. [PMID: 27797822 PMCID: PMC5167345 DOI: 10.15252/embj.201694818] [Citation(s) in RCA: 171] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 07/25/2016] [Accepted: 10/07/2016] [Indexed: 12/20/2022] Open
Abstract
The emergence of proteomics has led to major technological advances in mass spectrometry (MS). These advancements not only benefitted MS-based high-throughput proteomics but also increased the impact of mass spectrometry on the field of structural and molecular biology. Here, we review how state-of-the-art MS methods, including native MS, top-down protein sequencing, cross-linking-MS, and hydrogen-deuterium exchange-MS, nowadays enable the characterization of biomolecular structures, functions, and interactions. In particular, we focus on the role of mass spectrometry in integrated structural and molecular biology investigations of biological macromolecular complexes and cellular machineries, highlighting work on CRISPR-Cas systems and eukaryotic transcription complexes.
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Affiliation(s)
- Philip Lössl
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, University of Utrecht, Utrecht, The Netherlands
- Netherlands Proteomics Center, Utrecht, The Netherlands
| | - Michiel van de Waterbeemd
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, University of Utrecht, Utrecht, The Netherlands
- Netherlands Proteomics Center, Utrecht, The Netherlands
| | - Albert Jr Heck
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, University of Utrecht, Utrecht, The Netherlands
- Netherlands Proteomics Center, Utrecht, The Netherlands
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32
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Barr JD, Shi L, Russell DH, Clemmer DE, Holliday AE. Following a Folding Transition with Capillary Electrophoresis and Ion Mobility Spectrometry. Anal Chem 2016; 88:10933-10939. [PMID: 27809500 DOI: 10.1021/acs.analchem.6b02424] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Ion mobility spectrometry (IMS) is increasingly used to describe solution-phase phenomena and has recently been used to establish the presence of multiple intermediates during the folding of a model polypeptide, polyproline. These observations, however, are made on gas-phase structures. Capillary electrophoresis (CE) is a complementary solution-phase technique, also based on the separation of charged species as a function of size and charge. Here, both ion mobility and capillary electrophoresis are used to follow the folding transition of a 13-mer polyproline peptide from the all-cis polyproline I (PPI) conformation to the all-trans polyproline II (PPII) conformation upon immersion in aqueous solvent. Synchronous folding processes are observed using both techniques. Eight conformers are observed using ion mobility. Although only five peaks are observed using capillary electrophoresis, these peaks can be modeled as sums of the observed IMS conformers; this is strong evidence that ion mobility is sampling solution-phase structures. CE measurements provide the first direct evidence that multiple folding intermediates are present in solution.
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Affiliation(s)
- John D Barr
- Department of Chemistry, Moravian College , Bethlehem, Pennsylvania 18018, United States
| | - Liuqing Shi
- Department of Chemistry, Indiana University , Bloomington, Indiana 47405, United States
| | - David H Russell
- Department of Chemistry, Texas A&M University , College Station, Texas 77843, United States
| | - David E Clemmer
- Department of Chemistry, Indiana University , Bloomington, Indiana 47405, United States
| | - Alison E Holliday
- Department of Chemistry, Moravian College , Bethlehem, Pennsylvania 18018, United States
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33
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Commodore JJ, Cassady CJ. The Effects of Trivalent Lanthanide Cationization on the Electron Transfer Dissociation of Acidic Fibrinopeptide B and its Analogs. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2016; 27:1499-509. [PMID: 27294379 PMCID: PMC4974135 DOI: 10.1007/s13361-016-1428-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 05/22/2016] [Accepted: 05/23/2016] [Indexed: 05/08/2023]
Abstract
Electrospray ionization (ESI) on mixtures of acidic fibrinopeptide B and two peptide analogs with trivalent lanthanide salts generates [M + Met + H](4+), [M + Met](3+), and [M + Met -H](2+), where M = peptide and Met = metal (except radioactive promethium). These ions undergo extensive and highly efficient electron transfer dissociation (ETD) to form metallated and non-metallated c- and z-ions. All metal adducted product ions contain at least two acidic sites, which suggest attachment of the lanthanide cation at the side chains of one or more acidic residues. The three peptides undergo similar fragmentation. ETD on [M + Met + H](4+) leads to cleavage at every residue; the presence of both a metal ion and an extra proton is very effective in promoting sequence-informative fragmentation. Backbone dissociation of [M + Met](3+) is also extensive, although cleavage does not always occur between adjacent glutamic acid residues. For [M + Met - H ](2+), a more limited range of product ions form. All lanthanide metal peptide complexes display similar fragmentation except for europium (Eu). ETD on [M + Eu - H](2+) and [M + Eu](3+) yields a limited amount of peptide backbone cleavage; however, [M + Eu + H](4+) dissociates extensively with cleavage at every residue. With the exception of the results for Eu(III), metallated peptide ion formation by ESI, ETD fragmentation efficiencies, and product ion formation are unaffected by the identity of the lanthanide cation. Adduction with trivalent lanthanide metal ions is a promising tool for sequence analysis of acidic peptides by ETD. Graphical Abstract ᅟ.
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Affiliation(s)
| | - Carolyn J Cassady
- Department of Chemistry, The University of Alabama, Tuscaloosa, AL, 35487, USA.
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34
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Campbell JL, Yang AMC, Melo LR, Hopkins WS. Studying Gas-Phase Interconversion of Tautomers Using Differential Mobility Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2016; 27:1277-1284. [PMID: 27094827 DOI: 10.1007/s13361-016-1392-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 03/08/2016] [Accepted: 03/17/2016] [Indexed: 06/05/2023]
Abstract
In this study, we report on the use of differential mobility spectrometry (DMS) as a tool for studying tautomeric species, allowing a more in-depth interrogation of these elusive isomers using ion/molecule reactions and tandem mass spectrometry. As an example, we revisit a case study in which gas-phase hydrogen-deuterium exchange (HDX)-a probe of ion structure in mass spectrometry-actually altered analyte ion structure by tautomerization. For the N- and O-protonated tautomers of 4-aminobenzoic acid, when separated using DMS and subjected to subsequent HDX with trace levels of D2O, the anticipated difference between the exchange rates of the two tautomers is observed. However, when using higher levels of D2O or a more basic reagent, equivalent and almost complete exchange of all labile protons is observed. This second observation is a result of the interconversion of the N-protonated tautomer to the O-protonated form during HDX. We can monitor this transformation experimentally, with support from detailed molecular dynamics and electronic structure calculations. In fact, calculations suggest the onset of bulk solution phase properties for 4-aminobenzoic acid upon solvation with eight CH3OH molecules. These findings also underscore the need for choosing HDX reagents and conditions judiciously when separating interconvertible isomers using DMS. Graphical Abstract ᅟ.
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Affiliation(s)
- J Larry Campbell
- SCIEX, 71 Four Valley Drive, Concord, ON, Canada, L4K 4V8.
- Department of Chemistry, University of Waterloo, 200 University Ave. West, Waterloo, ON, Canada, N2L 3G1.
| | - Amy Meng-Ci Yang
- Department of Chemistry, University of Waterloo, 200 University Ave. West, Waterloo, ON, Canada, N2L 3G1
| | - Luke R Melo
- Department of Chemistry, University of Waterloo, 200 University Ave. West, Waterloo, ON, Canada, N2L 3G1
| | - W Scott Hopkins
- Department of Chemistry, University of Waterloo, 200 University Ave. West, Waterloo, ON, Canada, N2L 3G1.
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35
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Loo RRO, Loo JA. Salt Bridge Rearrangement (SaBRe) Explains the Dissociation Behavior of Noncovalent Complexes. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2016; 27:975-90. [PMID: 27052739 PMCID: PMC4865452 DOI: 10.1007/s13361-016-1375-3] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2016] [Revised: 02/28/2016] [Accepted: 03/01/2016] [Indexed: 05/11/2023]
Abstract
Native electrospray ionization-mass spectrometry, with gas-phase activation and solution compositions that partially release subcomplexes, can elucidate topologies of macromolecular assemblies. That so much complexity can be preserved in gas-phase assemblies is remarkable, although a long-standing conundrum has been the differences between their gas- and solution-phase decompositions. Collision-induced dissociation of multimeric noncovalent complexes typically distributes products asymmetrically (i.e., by ejecting a single subunit bearing a large percentage of the excess charge). That unexpected behavior has been rationalized as one subunit "unfolding" to depart with more charge. We present an alternative explanation based on heterolytic ion-pair scission and rearrangement, a mechanism that inherently partitions charge asymmetrically. Excessive barriers to dissociation are circumvented in this manner, when local charge rearrangements access a lower-barrier surface. An implication of this ion pair consideration is that stability differences between high- and low-charge state ions usually attributed to Coulomb repulsion may, alternatively, be conveyed by attractive forces from ion pairs (salt bridges) stabilizing low-charge state ions. Should the number of ion pairs be roughly inversely related to charge, symmetric dissociations would be favored from highly charged complexes, as observed. Correlations between a gas-phase protein's size and charge reflect the quantity of restraining ion pairs. Collisionally-facilitated salt bridge rearrangement (SaBRe) may explain unusual size "contractions" seen for some activated, low charge state complexes. That some low-charged multimers preferentially cleave covalent bonds or shed small ions to disrupting noncovalent associations is also explained by greater ion pairing in low charge state complexes. Graphical Abstract ᅟ.
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Affiliation(s)
- Rachel R Ogorzalek Loo
- Department of Biological Chemistry, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, CA, 90095, USA.
| | - Joseph A Loo
- Department of Biological Chemistry, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, CA, 90095, USA.
- UCLA/DOE Institute for Genomics and Proteomics, University of California-Los Angeles, Los Angeles, CA, 90095, USA.
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, CA, 90095, USA.
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36
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Khakinejad M, Kondalaji SG, Donohoe GC, Valentine SJ. Ion Mobility Spectrometry-Hydrogen Deuterium Exchange Mass Spectrometry of Anions: Part 2. Assessing Charge Site Location and Isotope Scrambling. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2016; 27:451-61. [PMID: 26802030 PMCID: PMC4814291 DOI: 10.1007/s13361-015-1304-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 10/28/2015] [Accepted: 11/02/2015] [Indexed: 05/17/2023]
Abstract
Ion mobility spectrometry (IMS) coupled with gas-phase hydrogen deuterium exchange (HDX)-mass spectrometry (MS) and molecular dynamic simulations (MDS) has been used for structural investigation of anions produced by electrospraying a sample containing a synthetic peptide having the sequence KKDDDDDIIKIIK. In these experiments the potential of the analytical method for locating charge sites on ions as well as for utilizing collision-induced dissociation (CID) to reveal the degree of deuterium uptake within specific amino acid residues has been assessed. For diffuse (i.e., more elongated) [M - 2H](2-) ions, decreased deuterium content along with MDS data suggest that the D4 and D6 residues are charge sites, whereas for the more diffuse [M - 3H](3-) ions, the data suggest that the D4, D7, and the C-terminus are deprotonated. Fragmentation of mobility-selected, diffuse [M - 2H](2-) ions to determine deuterium uptake at individual amino acid residues reveals a degree of deuterium retention at incorporation sites. Although the diffuse [M - 3H](3-) ions may show more HD scrambling, it is not possible to clearly distinguish HD scrambling from the expected deuterium uptake based on a hydrogen accessibility model. The capability of the IMS-HDX-MS/MS approach to provide relevant details about ion structure is discussed. Additionally, the ability to extend the approach for locating protonation sites on positively-charged ions is presented.
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Affiliation(s)
- Mahdiar Khakinejad
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA
| | | | - Gregory C Donohoe
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA
| | - Stephen J Valentine
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA.
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37
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Mistarz UH, Brown JM, Haselmann KF, Rand KD. Probing the Binding Interfaces of Protein Complexes Using Gas-Phase H/D Exchange Mass Spectrometry. Structure 2015; 24:310-8. [PMID: 26749447 DOI: 10.1016/j.str.2015.11.013] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Revised: 11/16/2015] [Accepted: 11/23/2015] [Indexed: 12/20/2022]
Abstract
Fast gas-phase hydrogen/deuterium exchange mediated by ND3 gas and measured by mass spectrometry (gas-phase HDX-MS) is a largely unharnessed, fast, and sensitive method for probing primary- and higher-order polypeptide structure. Labeling of heteroatom-bound non-amide hydrogens in a sub-millisecond time span after electrospray ionization by ND3 gas can provide structural insights into protein conformers present in solution. Here, we have explored the use of gas-phase HDX-MS for probing the higher-order structure and binding interfaces of protein complexes originating from native solution conditions. Lysozyme ions bound by an oligosaccharide incorporated less deuterium than the unbound ion. Similarly, trypsin ions showed reduced deuterium uptake when bound by the peptide ligand vasopressin. Our results are in good agreement with crystal structures of the native protein complexes, and illustrate that gas-phase HDX-MS can provide a sensitive and simple approach to measure the number of heteroatom-bound non-amide side-chain hydrogens involved in the binding interface of biologically relevant protein complexes.
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Affiliation(s)
- Ulrik H Mistarz
- Department of Pharmacy, University of Copenhagen, Universitetsparken 2, Copenhagen 2100, Denmark
| | - Jeffery M Brown
- Waters MS Technologies Centre, Waters Corporation, Altrincham Road, Wilmslow SK9 4AX, UK
| | - Kim F Haselmann
- Diabetes Protein Engineering, Novo Nordisk A/S, Novo Nordisk Park 1, Måløv 2670, Denmark
| | - Kasper D Rand
- Department of Pharmacy, University of Copenhagen, Universitetsparken 2, Copenhagen 2100, Denmark.
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38
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Stover ML, Plummer CE, Miller SR, Cassady CJ, Dixon DA. Gas-Phase Acidities of Phosphorylated Amino Acids. J Phys Chem B 2015; 119:14604-21. [DOI: 10.1021/acs.jpcb.5b08616] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Michele L. Stover
- Chemistry
Department, Shelby
Hall, The University of Alabama, Shelby Hall, Box
870336, Tuscaloosa, Alabama 35487-0336, United States
| | - Chelsea E. Plummer
- Chemistry
Department, Shelby
Hall, The University of Alabama, Shelby Hall, Box
870336, Tuscaloosa, Alabama 35487-0336, United States
| | - Sean R. Miller
- Chemistry
Department, Shelby
Hall, The University of Alabama, Shelby Hall, Box
870336, Tuscaloosa, Alabama 35487-0336, United States
| | - Carolyn J. Cassady
- Chemistry
Department, Shelby
Hall, The University of Alabama, Shelby Hall, Box
870336, Tuscaloosa, Alabama 35487-0336, United States
| | - David A. Dixon
- Chemistry
Department, Shelby
Hall, The University of Alabama, Shelby Hall, Box
870336, Tuscaloosa, Alabama 35487-0336, United States
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39
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Rajabi K, Ashcroft AE, Radford SE. Mass spectrometric methods to analyze the structural organization of macromolecular complexes. Methods 2015; 89:13-21. [DOI: 10.1016/j.ymeth.2015.03.004] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Revised: 02/25/2015] [Accepted: 03/06/2015] [Indexed: 01/14/2023] Open
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40
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Khakinejad M, Kondalaji SG, Tafreshian A, Valentine SJ. Gas-Phase Hydrogen-Deuterium Exchange Labeling of Select Peptide Ion Conformer Types: a Per-Residue Kinetics Analysis. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2015; 26:1115-1127. [PMID: 25895891 DOI: 10.1007/s13361-015-1127-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Revised: 02/26/2015] [Accepted: 03/05/2015] [Indexed: 06/04/2023]
Abstract
The per-residue, gas-phase hydrogen deuterium exchange (HDX) kinetics for individual amino acid residues on selected ion conformer types of the model peptide KKDDDDDIIKIIK have been examined using ion mobility spectrometry (IMS) and HDX-tandem mass spectrometry (MS/MS) techniques. The [M + 4H](4+) ions exhibit two major conformer types with collision cross sections of 418 Å(2) and 446 Å(2); the [M + 3H](3+) ions also yield two different conformer types having collision cross sections of 340 Å(2) and 367 Å(2). Kinetics plots of HDX for individual amino acid residues reveal fast- and slow-exchanging hydrogens. The contributions of each amino acid residue to the overall conformer type rate constant have been estimated. For this peptide, N- and C-terminal K residues exhibit the greatest contributions for all ion conformer types. Interior D and I residues show decreased contributions. Several charge state trends are observed. On average, the D residues of the [M + 3H](3+) ions show faster HDX rate contributions compared with [M + 4H](4+) ions. In contrast the interior I8 and I9 residues show increased accessibility to exchange for the more elongated [M + 4H](4+) ion conformer type. The contribution of each residue to the overall uptake rate showed a good correlation with a residue hydrogen accessibility score model calculated using a distance from charge site and initial incorporation site for nominal structures obtained from molecular dynamic simulations (MDS).
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Affiliation(s)
- Mahdiar Khakinejad
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA
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41
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Schenk ER, Almeida R, Miksovska J, Ridgeway ME, Park MA, Fernandez-Lima F. Kinetic intermediates of holo- and apo-myoglobin studied using HDX-TIMS-MS and molecular dynamic simulations. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2015; 26:555-63. [PMID: 25690175 PMCID: PMC4402236 DOI: 10.1007/s13361-014-1067-9] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Revised: 12/01/2014] [Accepted: 12/07/2014] [Indexed: 05/05/2023]
Abstract
In the present work, the kinetic intermediates of holo- and apo-myoglobin were studied by correlating the ion-neutral collision cross section and time resolved H/D back exchange rate simultaneously in a trapped ion mobility spectrometer coupled to a mass spectrometer (HDX-TIMS-MS). The high mobility resolution of the TIMS cell permitted the observation of multiple IMS bands and complementary molecular dynamics simulations resulted in the assignment of candidate structures for each experimental condition studied (e.g., holo [M + 8H](+8)-[M + 9H](+9) and apo [M + 9H](+9)-[M + 19H](+19)). Inspection of the kinetic intermediates suggests that the tertiary structure of apomyoglobin unfolds quickly upon the loss of the Fe protoporphyrin IX that stabilizes the interactions between the A, G, and H helices. In the absence of the porphyrin heme, the apomyoglobin unfolds to Xn kinetic intermediates that vary in the extent of unfolding as a result of the observed charge state.
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Affiliation(s)
- Emily R. Schenk
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, USA
- Biomolecular Sciences Institute, Florida International University, Miami, FL 33199, USA
| | - Raybel Almeida
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, USA
| | - Jaroslava Miksovska
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, USA
| | | | | | - Francisco Fernandez-Lima
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, USA
- Biomolecular Sciences Institute, Florida International University, Miami, FL 33199, USA
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42
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Donohoe GC, Khakinejad M, Valentine SJ. Ion mobility spectrometry-hydrogen deuterium exchange mass spectrometry of anions: part 1. Peptides to proteins. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2015; 26:564-576. [PMID: 25510931 DOI: 10.1007/s13361-014-1045-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 10/28/2014] [Accepted: 10/28/2014] [Indexed: 06/04/2023]
Abstract
Ion mobility spectrometry (IMS) coupled with hydrogen deuterium exchange (HDX)-mass spectrometry (MS) has been used to study the conformations of negatively-charged peptide and protein ions. Results are presented for ion conformers of angiotensin 1, a synthetic peptide (SP), bovine insulin, ubiquitin, and equine cytochrome c. In general, the SP ion conformers demonstrate a greater level of HDX efficiency as a greater proportion of the sites undergo HDX. Additionally, these ions exhibit the fastest rates of exchange. Comparatively, the angiotensin 1 ions exhibit a lower rate of exchange and HDX level presumably because of decreased accessibility of exchange sites by charge sites. The latter are likely confined to the peptide termini. Insulin ions show dramatically reduced HDX levels and exchange rates, which can be attributed to decreased conformational flexibility resulting from the disulfide bonds. For the larger ubiquitin and protein ions, increased HDX is observed for larger ions of higher charge state. For ubiquitin, a conformational transition from compact to more elongated species (from lower to higher charge states) is reflected by an increase in HDX levels. These results can be explained by a combination of interior site protection by compact conformers as well as decreased access by charge sites. The elongated cytochrome c ions provide the largest HDX levels where higher values correlate with charge state. These results are consistent with increased exchange site accessibility by additional charge sites. The data from these enhanced IMS-HDX experiments are described in terms of charge site location, conformer rigidity, and interior site protection.
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Affiliation(s)
- Gregory C Donohoe
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA
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43
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Going CC, Williams ER. Supercharging with m-Nitrobenzyl Alcohol and Propylene Carbonate: Forming Highly Charged Ions with Extended, Near-Linear Conformations. Anal Chem 2015; 87:3973-80. [DOI: 10.1021/acs.analchem.5b00071] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Catherine C. Going
- Department
of Chemistry, University of California, Berkeley, Berkeley, California 94720-1460, United States
| | - Evan R. Williams
- Department
of Chemistry, University of California, Berkeley, Berkeley, California 94720-1460, United States
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44
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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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45
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Xiao C, Pérez LM, Russell DH. Effects of charge states, charge sites and side chain interactions on conformational preferences of a series of model peptide ions. Analyst 2015; 140:6933-44. [DOI: 10.1039/c5an00826c] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The factors affecting conformational preference of gas phase peptide ions are investigated by IM-MS and molecular dynamics simulation.
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Affiliation(s)
- Chunying Xiao
- Texas A&M University
- Department of Chemistry
- College Station
- USA
| | - Lisa M. Pérez
- Texas A&M University
- Department of Chemistry
- College Station
- USA
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46
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Zhu F, Glover MS, Shi H, Trinidad JC, Clemmer DE. Populations of metal-glycan structures influence MS fragmentation patterns. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2015; 26:25-35. [PMID: 25315458 PMCID: PMC4276451 DOI: 10.1007/s13361-014-1000-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Revised: 09/04/2014] [Accepted: 09/07/2014] [Indexed: 05/19/2023]
Abstract
The structures and collision-induced dissociation (CID) fragmentation patterns of the permethylated glycan Man5GlcNAc2 are investigated by a combination of hybrid ion mobility spectrometry (IMS), mass spectrometry (MS), and MS/MS techniques. IMS analysis of eight metal-adducted glycans ([Man5GlcNAc2 + M](2+), where M = Mn, Fe, Co, Ni, Cu, Mg, Ca, and Ba) shows distinct conformer patterns. These conformers appear to arise from individual metals binding at different sites on the glycan. Fragmentation studies suggest that these different binding sites influence the CID fragmentation patterns. This paper describes a series of separation, activation, and fragmentation studies that assess which fragments arise from each of the different gas-phase conformer states. Comparison of the glycan distributions formed under gentle ionization conditions with those obtained after activation of the gas-phase ions suggests that these conformer binding states also appear to exist in solution.
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Affiliation(s)
- Feifei Zhu
- Department of Chemistry, Indiana University, 800 Kirkwood Ave. Bloomington, IN 47405
| | - Matthew S. Glover
- Department of Chemistry, Indiana University, 800 Kirkwood Ave. Bloomington, IN 47405
| | - Huilin Shi
- Department of Chemistry, Indiana University, 800 Kirkwood Ave. Bloomington, IN 47405
| | - Jonathan C. Trinidad
- Department of Chemistry, Indiana University, 800 Kirkwood Ave. Bloomington, IN 47405
| | - David E. Clemmer
- Department of Chemistry, Indiana University, 800 Kirkwood Ave. Bloomington, IN 47405
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47
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Rajabi K. Time-resolved pulsed hydrogen/deuterium exchange mass spectrometry probes gaseous proteins structural kinetics. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2015; 26:71-82. [PMID: 25318698 DOI: 10.1007/s13361-014-1004-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Revised: 09/10/2014] [Accepted: 09/11/2014] [Indexed: 06/04/2023]
Abstract
A pulsed hydrogen/deuterium exchange (HDX) method has been developed for rapid monitoring of the exchange kinetics of protein ions with D2O a few milliseconds after electrospray ionization (ESI). The stepwise gradual evolution of HDX of multiply charged protein ions was monitored using the pulsed HDX mass spectrometry technique. Upon introducing a very short pulse of D2O (in the μs to ms time scale) into the linear ion trap (LIT) of a time-of-flight (TOF) mass spectrometer, bimodal distributions were detected for the ions of cytochrome c and ubiquitin. Mechanistic details of HDX reactions for ubiquitin and cytochrome c in the gas phase were uncovered and the structural transitions were followed by analyzing the kinetics of HDX.
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Affiliation(s)
- Khadijeh Rajabi
- Department of Chemistry, University of British Columbia (UBC), 2036 Mail Mall, Vancouver, BC, V6T 1Z1, Canada,
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48
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Khakinejad M, Kondalaji SG, Maleki H, Arndt JR, Donohoe GC, Valentine SJ. Combining ion mobility spectrometry with hydrogen-deuterium exchange and top-down MS for peptide ion structure analysis. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2014; 25:2103-15. [PMID: 25267084 DOI: 10.1007/s13361-014-0990-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Revised: 08/20/2014] [Accepted: 08/20/2014] [Indexed: 05/25/2023]
Abstract
The gas-phase conformations of electrosprayed ions of the model peptide KKDDDDIIKIIK have been examined by ion mobility spectrometry (IMS) and hydrogen deuterium exchange (HDX)-tandem mass spectrometry (MS/MS) techniques. [M+4H](4+) ions exhibit two conformers with collision cross sections of 418 Å(2) and 471 Å(2). [M+3H](3+) ions exhibit a predominant conformer with a collision cross section of 340 Å(2) as well as an unresolved conformer (shoulder) with a collision cross section of ~367 Å(2). Maximum HDX levels for the more compact [M+4H](4+) ions and the compact and partially-folded [M+3H](3+) ions are ~12.9, ~15.5, and ~14.9, respectively. Ion structures obtained from molecular dynamics simulations (MDS) suggest that this ordering of HDX level results from increased charge-site/exchange-site density for the more compact ions of lower charge. Additionally, a new model that includes two distance calculations (charge site to carbonyl group and carbonyl group to exchange site) for the computer-generated structures is shown to better correlate to the experimentally determined per-residue deuterium uptake. Future comparisons of IMS-HDX-MS data with structures obtained from MDS are discussed with respect to novel experiments that will reveal the HDX rates of individual residues.
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Affiliation(s)
- Mahdiar Khakinejad
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA
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49
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Mistarz UH, Brown JM, Haselmann KF, Rand KD. Simple setup for gas-phase H/D exchange mass spectrometry coupled to electron transfer dissociation and ion mobility for analysis of polypeptide structure on a liquid chromatographic time scale. Anal Chem 2014; 86:11868-76. [PMID: 25375223 DOI: 10.1021/ac5035456] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Gas-phase hydrogen/deuterium exchange (HDX) is a fast and sensitive, yet unharnessed analytical approach for providing information on the structural properties of biomolecules, in a complementary manner to mass analysis. Here, we describe a simple setup for ND3-mediated millisecond gas-phase HDX inside a mass spectrometer immediately after ESI (gas-phase HDX-MS) and show utility for studying the primary and higher-order structure of peptides and proteins. HDX was achieved by passing N2-gas through a container filled with aqueous deuterated ammonia reagent (ND3/D2O) and admitting the saturated gas immediately upstream or downstream of the primary skimmer cone. The approach was implemented on three commercially available mass spectrometers and required no or minor fully reversible reconfiguration of gas-inlets of the ion source. Results from gas-phase HDX-MS of peptides using the aqueous ND3/D2O as HDX reagent indicate that labeling is facilitated exclusively through gaseous ND3, yielding similar results to the infusion of purified ND3-gas, while circumventing the complications associated with the use of hazardous purified gases. Comparison of the solution-phase- and gas-phase deuterium uptake of Leu-Enkephalin and Glu-Fibrinopeptide B, confirmed that this gas-phase HDX-MS approach allows for labeling of sites (heteroatom-bound non-amide hydrogens located on side-chains, N-terminus and C-terminus) not accessed by classical solution-phase HDX-MS. The simple setup is compatible with liquid chromatography and a chip-based automated nanoESI interface, allowing for online gas-phase HDX-MS analysis of peptides and proteins separated on a liquid chromatographic time scale at increased throughput. Furthermore, online gas-phase HDX-MS could be performed in tandem with ion mobility separation or electron transfer dissociation, thus enabling multiple orthogonal analyses of the structural properties of peptides and proteins in a single automated LC-MS workflow.
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Affiliation(s)
- Ulrik H Mistarz
- Department of Pharmacy, University of Copenhagen , Universitetsparken 2, 2100 Copenhagen, Denmark
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50
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Shi L, Holliday AE, Shi H, Zhu F, Ewing MA, Russell DH, Clemmer DE. Characterizing Intermediates Along the Transition from Polyproline I to Polyproline II Using Ion Mobility Spectrometry-Mass Spectrometry. J Am Chem Soc 2014; 136:12702-11. [DOI: 10.1021/ja505899g] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Liuqing Shi
- Department
of Chemistry, Indiana University, 800 Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Alison E. Holliday
- Department
of Chemistry and Biochemistry, Swarthmore College, Swarthmore, Pennsylvania 19081, United States
| | - Huilin Shi
- Department
of Chemistry, Indiana University, 800 Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Feifei Zhu
- Department
of Chemistry, Indiana University, 800 Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Michael A. Ewing
- Department
of Chemistry, Indiana University, 800 Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - David H. Russell
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - David E. Clemmer
- Department
of Chemistry, Indiana University, 800 Kirkwood Avenue, Bloomington, Indiana 47405, United States
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