1
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Jiang Y, Rex DA, Schuster D, Neely BA, Rosano GL, Volkmar N, Momenzadeh A, Peters-Clarke TM, Egbert SB, Kreimer S, Doud EH, Crook OM, Yadav AK, Vanuopadath M, Hegeman AD, Mayta M, Duboff AG, Riley NM, Moritz RL, Meyer JG. Comprehensive Overview of Bottom-Up Proteomics Using Mass Spectrometry. ACS MEASUREMENT SCIENCE AU 2024; 4:338-417. [PMID: 39193565 PMCID: PMC11348894 DOI: 10.1021/acsmeasuresciau.3c00068] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 05/03/2024] [Accepted: 05/03/2024] [Indexed: 08/29/2024]
Abstract
Proteomics is the large scale study of protein structure and function from biological systems through protein identification and quantification. "Shotgun proteomics" or "bottom-up proteomics" is the prevailing strategy, in which proteins are hydrolyzed into peptides that are analyzed by mass spectrometry. Proteomics studies can be applied to diverse studies ranging from simple protein identification to studies of proteoforms, protein-protein interactions, protein structural alterations, absolute and relative protein quantification, post-translational modifications, and protein stability. To enable this range of different experiments, there are diverse strategies for proteome analysis. The nuances of how proteomic workflows differ may be challenging to understand for new practitioners. Here, we provide a comprehensive overview of different proteomics methods. We cover from biochemistry basics and protein extraction to biological interpretation and orthogonal validation. We expect this Review will serve as a handbook for researchers who are new to the field of bottom-up proteomics.
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Affiliation(s)
- Yuming Jiang
- Department
of Computational Biomedicine, Cedars Sinai
Medical Center, Los Angeles, California 90048, United States
- Smidt Heart
Institute, Cedars Sinai Medical Center, Los Angeles, California 90048, United States
- Advanced
Clinical Biosystems Research Institute, Cedars Sinai Medical Center, Los
Angeles, California 90048, United States
| | - Devasahayam Arokia
Balaya Rex
- Center for
Systems Biology and Molecular Medicine, Yenepoya Research Centre, Yenepoya (Deemed to be University), Mangalore 575018, India
| | - Dina Schuster
- Department
of Biology, Institute of Molecular Systems
Biology, ETH Zurich, Zurich 8093, Switzerland
- Department
of Biology, Institute of Molecular Biology
and Biophysics, ETH Zurich, Zurich 8093, Switzerland
- Laboratory
of Biomolecular Research, Division of Biology and Chemistry, Paul Scherrer Institute, Villigen 5232, Switzerland
| | - Benjamin A. Neely
- Chemical
Sciences Division, National Institute of
Standards and Technology, NIST, Charleston, South Carolina 29412, United States
| | - Germán L. Rosano
- Mass
Spectrometry
Unit, Institute of Molecular and Cellular
Biology of Rosario, Rosario, 2000 Argentina
| | - Norbert Volkmar
- Department
of Biology, Institute of Molecular Systems
Biology, ETH Zurich, Zurich 8093, Switzerland
| | - Amanda Momenzadeh
- Department
of Computational Biomedicine, Cedars Sinai
Medical Center, Los Angeles, California 90048, United States
- Smidt Heart
Institute, Cedars Sinai Medical Center, Los Angeles, California 90048, United States
- Advanced
Clinical Biosystems Research Institute, Cedars Sinai Medical Center, Los
Angeles, California 90048, United States
| | - Trenton M. Peters-Clarke
- Department
of Pharmaceutical Chemistry, University
of California—San Francisco, San Francisco, California, 94158, United States
| | - Susan B. Egbert
- Department
of Chemistry, University of Manitoba, Winnipeg, Manitoba, R3T 2N2 Canada
| | - Simion Kreimer
- Smidt Heart
Institute, Cedars Sinai Medical Center, Los Angeles, California 90048, United States
- Advanced
Clinical Biosystems Research Institute, Cedars Sinai Medical Center, Los
Angeles, California 90048, United States
| | - Emma H. Doud
- Center
for Proteome Analysis, Indiana University
School of Medicine, Indianapolis, Indiana, 46202-3082, United States
| | - Oliver M. Crook
- Oxford
Protein Informatics Group, Department of Statistics, University of Oxford, Oxford OX1 3LB, United
Kingdom
| | - Amit Kumar Yadav
- Translational
Health Science and Technology Institute, NCR Biotech Science Cluster 3rd Milestone Faridabad-Gurgaon
Expressway, Faridabad, Haryana 121001, India
| | | | - Adrian D. Hegeman
- Departments
of Horticultural Science and Plant and Microbial Biology, University of Minnesota, Twin Cities, Minnesota 55108, United States
| | - Martín
L. Mayta
- School
of Medicine and Health Sciences, Center for Health Sciences Research, Universidad Adventista del Plata, Libertador San Martin 3103, Argentina
- Molecular
Biology Department, School of Pharmacy and Biochemistry, Universidad Nacional de Rosario, Rosario 2000, Argentina
| | - Anna G. Duboff
- Department
of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Nicholas M. Riley
- Department
of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Robert L. Moritz
- Institute
for Systems biology, Seattle, Washington 98109, United States
| | - Jesse G. Meyer
- Department
of Computational Biomedicine, Cedars Sinai
Medical Center, Los Angeles, California 90048, United States
- Smidt Heart
Institute, Cedars Sinai Medical Center, Los Angeles, California 90048, United States
- Advanced
Clinical Biosystems Research Institute, Cedars Sinai Medical Center, Los
Angeles, California 90048, United States
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2
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Gozzo TA, Bush MF. Effects of charge on protein ion structure: Lessons from cation-to-anion, proton-transfer reactions. MASS SPECTROMETRY REVIEWS 2024; 43:500-525. [PMID: 37129026 DOI: 10.1002/mas.21847] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 04/10/2023] [Accepted: 04/11/2023] [Indexed: 05/03/2023]
Abstract
Collision cross-section values, which can be determined using ion mobility experiments, are sensitive to the structures of protein ions and useful for applications to structural biology and biophysics. Protein ions with different charge states can exhibit very different collision cross-section values, but a comprehensive understanding of this relationship remains elusive. Here, we review cation-to-anion, proton-transfer reactions (CAPTR), a method for generating a series of charge-reduced protein cations by reacting quadrupole-selected cations with even-electron monoanions. The resulting CAPTR products are analyzed using a combination of ion mobility, mass spectrometry, and collisional activation. We compare CAPTR to other charge-manipulation strategies and review the results of various CAPTR-based experiments, exploring their contribution to a deeper understanding of the relationship between protein ion structure and charge state.
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Affiliation(s)
- Theresa A Gozzo
- Department of Chemistry, University of Washington, Seattle, Washington, USA
| | - Matthew F Bush
- Department of Chemistry, University of Washington, Seattle, Washington, USA
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3
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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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4
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Peters-Clarke TM, Riley NM, Westphall MS, Coon JJ. Practical Effects of Intramolecular Hydrogen Rearrangement in Electron Transfer Dissociation-Based Proteomics. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2022; 33:100-110. [PMID: 34874726 PMCID: PMC10291708 DOI: 10.1021/jasms.1c00284] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Ion-ion reactions are valuable tools in mass-spectrometry-based peptide and protein sequencing. To boost the generation of sequence-informative fragment ions from low charge-density precursors, supplemental activation methods, via vibrational and photoactivation, have become widely adopted. However, long-lived radical peptide cations undergo intramolecular hydrogen atom transfer from c-type ions to z•-type ions. Here we investigate the degree of hydrogen transfer for thousands of unique peptide cations where electron transfer dissociation (ETD) was performed and was followed by beam-type collisional activation (EThcD), resonant collisional activation (ETcaD), or concurrent infrared photoirradiation (AI-ETD). We report on the precursor charge density and the local amino acid environment surrounding bond cleavage to illustrate the effects of intramolecular hydrogen atom transfer for various precursor ions. Over 30% of fragments from EThcD spectra comprise distorted isotopic distributions, whereas over 20% of fragments from ETcaD have distorted distributions and less than 15% of fragments derived from ETD and AI-ETD reveal distorted isotopic distributions. Both ETcaD and EThcD give a relatively high degree of hydrogen migration, especially when D, G, N, S, and T residues were directly C-terminal to the cleavage site. Whereas all postactivation methods boost the number of c- and z•-type fragment ions detected, the collision-based approaches produce higher rates of hydrogen migration, yielding fewer spectral identifications when only c- and z•-type ions are considered. Understanding hydrogen rearrangement between c- and z•-type ions will facilitate better spectral interpretation.
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Affiliation(s)
- Trenton M Peters-Clarke
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Nicholas M Riley
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Michael S Westphall
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
- National Center for Quantitative Biology of Complex Systems, Madison, Wisconsin 53706, United States
| | - Joshua J Coon
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
- National Center for Quantitative Biology of Complex Systems, Madison, Wisconsin 53706, United States
- Morgridge Institute for Research, Madison, Wisconsin 53515, United States
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5
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Prian K, Aloui I, Legros V, Buchmann W. Study of the gas-phase decomposition of multiply lithiated polycaprolactone, polytetrahydrofurane and their copolymer by two different activation methods: Collision-induced dissociation and electron transfer dissociation. Anal Chim Acta 2019; 1048:85-95. [DOI: 10.1016/j.aca.2018.10.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 09/28/2018] [Accepted: 10/02/2018] [Indexed: 01/24/2023]
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6
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Lermyte F, Valkenborg D, Loo JA, Sobott F. Radical solutions: Principles and application of electron-based dissociation in mass spectrometry-based analysis of protein structure. MASS SPECTROMETRY REVIEWS 2018; 37:750-771. [PMID: 29425406 PMCID: PMC6131092 DOI: 10.1002/mas.21560] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 01/19/2018] [Accepted: 01/19/2018] [Indexed: 05/11/2023]
Abstract
In recent years, electron capture (ECD) and electron transfer dissociation (ETD) have emerged as two of the most useful methods in mass spectrometry-based protein analysis, evidenced by a considerable and growing body of literature. In large part, the interest in these methods is due to their ability to induce backbone fragmentation with very little disruption of noncovalent interactions which allows inference of information regarding higher order structure from the observed fragmentation behavior. Here, we review the evolution of electron-based dissociation methods, and pay particular attention to their application in "native" mass spectrometry, their mechanism, determinants of fragmentation behavior, and recent developments in available instrumentation. Although we focus on the two most widely used methods-ECD and ETD-we also discuss the use of other ion/electron, ion/ion, and ion/neutral fragmentation methods, useful for interrogation of a range of classes of biomolecules in positive- and negative-ion mode, and speculate about how this exciting field might evolve in the coming years.
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Affiliation(s)
- Frederik Lermyte
- Biomolecular and Analytical Mass Spectrometry Group, Department of Chemistry, University of Antwerp, Antwerp, Belgium
- Centre for Proteomics, University of Antwerp, Antwerp, Belgium
- School of Engineering, University of Warwick, Coventry, United Kingdom
| | - Dirk Valkenborg
- Centre for Proteomics, University of Antwerp, Antwerp, Belgium
- Interuniversity Institute for Biostatistics and Statistical Bioinformatics, Hasselt University, Agoralaan, Diepenbeek, Belgium
- Applied Bio and Molecular Systems, Flemish Institute for Technological Research (VITO), Mol, Belgium
| | - Joseph A Loo
- Department of Biological Chemistry, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, California
- UCLA/DOE Institute for Genomics and Proteomics, University of California-Los Angeles, Los Angeles, California
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, California
| | - Frank Sobott
- Biomolecular and Analytical Mass Spectrometry Group, Department of Chemistry, University of Antwerp, Antwerp, Belgium
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom
- School of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
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7
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Chen X, Wang Z, Wong YLE, Wu R, Zhang F, Chan TWD. Electron-ion reaction-based dissociation: A powerful ion activation method for the elucidation of natural product structures. MASS SPECTROMETRY REVIEWS 2018; 37:793-810. [PMID: 29603345 DOI: 10.1002/mas.21563] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Accepted: 02/12/2018] [Indexed: 05/16/2023]
Abstract
The structural elucidation of natural products (NPs) remains a challenge due to their structurally diversities and unpredictable functionalities, motifs, and scaffolds. Tandem mass spectrometry (MS/MS) is an effective method that assists the full elucidation of complicated NP structures. Ion activation methods play a key role in determining the fragmentation pathways and the structural information obtained from MS/MS. Electron-ion reaction-based dissociation (ExD) methods, including electron capture dissociation (ECD), electron transfer dissociation (ETD), electron-induced dissociation (EID), and electron detachment dissociation (EDD), can induce the breakage of specific chemical bonds and the generation of distinct fragment ions. This review article provides an overview of the mechanisms, instrumentation, and typical applications related to ExD MS/MS in the structural elucidation of NPs, primarly including lipids, oligosaccharides, glycoconjugates, metabolites, and pharmaceutical drugs. This work aims to reveal the capacity and potential of ExD mass spectrometry in analyzing NPs and consequently helping the NP communities to utilize the modern capabilities of MS/MS in the discovery and evaluation of novel NPs.
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Affiliation(s)
- Xiangfeng Chen
- Key Laboratory for Applied Technology of Sophisticated Analytical Instruments, Shandong Analysis and Test Centre, Qilu University of Technology (Shandong Academy of Science), Shandong, P.R. China
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, P.R. China
| | - Ze Wang
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, P.R. China
| | - Y-L Elaine Wong
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, P.R. China
| | - Ri Wu
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, P.R. China
| | - Feng Zhang
- Chinese Academy of Inspection and Quarantine, Beijing, P. R. China
| | - T-W Dominic Chan
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, P.R. China
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8
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Nguyen HTH, Andrikopoulos PC, Rulíšek L, Shaffer CJ, Tureček F. Photodissociative Cross-Linking of Non-covalent Peptide-Peptide Ion Complexes in the Gas Phase. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2018; 29:1706-1720. [PMID: 29736598 DOI: 10.1007/s13361-018-1980-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 04/24/2018] [Accepted: 04/24/2018] [Indexed: 06/08/2023]
Abstract
We report a gas-phase UV photodissociation study investigating non-covalent interactions between neutral hydrophobic pentapeptides and peptide ions incorporating a diazirine-tagged photoleucine residue. Phenylalanine (Phe) and proline (Pro) were chosen as the conformation-affecting residues that were incorporated into a small library of neutral pentapeptides. Gas-phase ion-molecule complexes of these peptides with photo-labeled pentapeptides were subjected to photodissociation. Selective photocleavage of the diazirine ring at 355 nm formed short-lived carbene intermediates that underwent cross-linking by insertion into H-X bonds of the target peptide. The cross-link positions were established from collision-induced dissociation tandem mass spectra (CID-MS3) providing sequence information on the covalent adducts. Effects of the amino acid residue (Pro or Phe) and its position in the target peptide sequence were evaluated. For proline-containing peptides, interactions resulting in covalent cross-links in these complexes became more prominent as proline was moved towards the C-terminus of the target peptide sequence. The photocross-linking yields of phenylalanine-containing peptides depended on the position of both phenylalanine and photoleucine. Density functional theory calculations were used to assign structures of low-energy conformers of the (GLPMG + GLL*LK + H)+ complex. Born-Oppenheimer molecular dynamics trajectory calculations were used to capture the thermal motion in the complexes within 100 ps and determine close contacts between the incipient carbene and the H-X bonds in the target peptide. This provided atomic-level resolution of potential cross-links that aided spectra interpretation and was in agreement with experimental data. Graphical Abstract ᅟ.
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Affiliation(s)
- Huong T H Nguyen
- Department of Chemistry, Bagley Hall, University of Washington, Box 351700, Seattle, WA, 98195-1700, USA
| | - Prokopis C Andrikopoulos
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, 166 10, Prague, Czech Republic
- Laboratory of Biomolecular Recognition, Institute of Biotechnology, Czech Academy of Sciences, 252 50, Vestec, Czech Republic
| | - Lubomír Rulíšek
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, 166 10, Prague, Czech Republic
| | - Christopher J Shaffer
- Department of Chemistry, Bagley Hall, University of Washington, Box 351700, Seattle, WA, 98195-1700, USA
- Valspar Corporation, Minneapolis, MN, USA
| | - František Tureček
- Department of Chemistry, Bagley Hall, University of Washington, Box 351700, Seattle, WA, 98195-1700, USA.
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9
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Marek A, Nguyen HTH, Brož B, Tureček F. Stereospecific control of peptide gas-phase ion chemistry with cis and trans cyclo ornithine residues. JOURNAL OF MASS SPECTROMETRY : JMS 2018; 53:124-137. [PMID: 29150896 DOI: 10.1002/jms.4047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Revised: 11/02/2017] [Accepted: 11/06/2017] [Indexed: 06/07/2023]
Abstract
We report non-chiral amino acid residues cis- and trans-1,4-diaminocyclohexane-1-carboxylic acid (cyclo-ornithine, cO) that exhibit unprecedented stereospecific control of backbone dissociations of singly charged peptide cations and hydrogen-rich cation radicals produced by electron-transfer dissociation. Upon collision-induced dissociation (CID) in the slow heating regime, peptide cations containing trans-cO residues undergo facile backbone cleavages of amide bonds C-terminal to trans-cO. By contrast, peptides with cis-cO residues undergo dissociations at several amide bonds along the peptide ion backbone. Diastereoisomeric cO-containing peptides thus provide remarkably distinct tandem mass spectra. The stereospecific effect in CID of the trans-cO residue is explained by syn-facially directed proton transfer from the 4-ammonium group at cO to the C-terminal amide followed by neighboring group participation in the cleavage of the CO-NH bond, analogous to the aspartic acid and ornithine effects. Backbone dissociations of diastereoisomeric cO-containing peptide ions generate distinct [bn ]+ -type fragment ions that were characterized by CID-MS3 spectra. Stereospecific control is also reported for electron-transfer dissociation of cis- and trans-cO containing doubly charged peptide ions. The stereospecific effect upon electron transfer is related to the different conformations of doubly charged peptide ions that affect the electron attachment sites and ensuing N-Cα bond dissociations.
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Affiliation(s)
- Aleš Marek
- Department of Chemistry, University of Washington, Bagley Hall, Box 351700, Seattle, WA, 98195-1700, USA
- Czech Academy of Sciences, Institute of Organic Chemistry and Biochemistry, Prague, Czech Republic
| | - Huong T H Nguyen
- Department of Chemistry, University of Washington, Bagley Hall, Box 351700, Seattle, WA, 98195-1700, USA
| | - Břetislav Brož
- Czech Academy of Sciences, Institute of Organic Chemistry and Biochemistry, Prague, Czech Republic
| | - František Tureček
- Department of Chemistry, University of Washington, Bagley Hall, Box 351700, Seattle, WA, 98195-1700, USA
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10
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Qi Y, Volmer DA. Electron-based fragmentation methods in mass spectrometry: An overview. MASS SPECTROMETRY REVIEWS 2017; 36:4-15. [PMID: 26445267 DOI: 10.1002/mas.21482] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Revised: 07/03/2015] [Accepted: 07/03/2015] [Indexed: 05/21/2023]
Abstract
Tandem mass spectrometry (MS/MS) provides detailed information for structural characterization of biomolecules. The combination of electron capture dissociation (ECD) techniques with Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) often provides unique ion-electron reactions and fragmentation channels in MS/MS. ECD is often a complimentary, sometimes even a superior tool to conventional MS/MS techniques. This article is aimed at providing a short overview of ECD-based fragmentation techniques (ExD) and optimization of ECD experiments for FTICR mass analyzers. Most importantly, it is meant to pique the interest of potential users for this exciting research field. © 2015 Wiley Periodicals, Inc. Mass Spec Rev 36:4-15, 2017.
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Affiliation(s)
- Yulin Qi
- Institute of Bioanalytical Chemistry, Saarland University, Campus B2.2, Saarbrücken, 66123, Germany
| | - Dietrich A Volmer
- Institute of Bioanalytical Chemistry, Saarland University, Campus B2.2, Saarbrücken, 66123, Germany
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11
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Asakawa D, Yamashita A, Kawai S, Takeuchi T, Wada Y. N-Cα Bond Cleavage of Zinc-Polyhistidine Complexes in Electron Transfer Dissociation Mediated by Zwitterion Formation: Experimental Evidence and Theoretical Analysis of the Utah-Washington Model. J Phys Chem B 2016; 120:891-901. [PMID: 26673038 DOI: 10.1021/acs.jpcb.5b11118] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Electron capture dissociation (ECD) and electron transfer dissociation (ETD) of gas-phase ions are widely used for peptide/protein sequencing by mass spectrometry. To understand the general mechanism of ECD/ETD of peptides, we focused on the ETD fragmentation of metal-peptide complexes in the absence of remote protons. Since Zn(2+) strongly binds to neutral histidine residues in peptides, Zn(2+)-polyhistidine complexation does not generate any remote protons. However, in the absence of remote protons, electron transfer to the Zn(2+)-polyhistidine complex induced the N-Cα bond cleavage. The formation pathway for the ETD products was investigated by density functional theory calculations. The calculations showed that the charge-reduced zinc-peptide radical, [M + Zn](•+), can exist in the low-energy zwitterionic amide π* states, which underwent homolytic N-Cα bond dissociation. The homolytic cleavage resulted in the donation of an electron from the N-Cα bond to the nitrogen atom, producing an iminoenol c' anion. The counterpart z(•) radical contained a radical site on the α-carbon atom. The iminoenol c' anion then abstracted a proton to presumably form the more stable amide c' fragment. The current experimental and computational joint study strongly suggested that the N-Cα bond cleavage occurred through the aminoketyl radical-anion formation for Zn(2+)-polyhistidine complexes in ETD.
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Affiliation(s)
- Daiki Asakawa
- National Metrology Institute of Japan (NMIJ), Research Institute for Measurement and Analytical Instrumentation, National Institute of Advanced Industrial Science and Technology (AIST) , Tsukuba Central 2, Umezono 1-1-1, Tsukuba, Ibaraki, 305-8568, Japan
| | - Asuka Yamashita
- Department of Chemistry, Faculty of Science, Nara Women's University , Kitauoyanishi-machi, Nara, 630-8506, Japan
| | - Shikiho Kawai
- Department of Chemistry, Faculty of Science, Nara Women's University , Kitauoyanishi-machi, Nara, 630-8506, Japan
| | - Takae Takeuchi
- Department of Chemistry, Faculty of Science, Nara Women's University , Kitauoyanishi-machi, Nara, 630-8506, Japan
| | - Yoshinao Wada
- Department of Molecular Medicine, Osaka Medical Center and Research Institute for Maternal and Child Health , Murodo-cho 840, Izumi, Osaka, 594-1101, Japan
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12
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Shi S, Szostak M. Aminoketyl Radicals in Organic Synthesis: Stereoselective Cyclization of Five- and Six-Membered Cyclic Imides to 2-Azabicycles Using SmI2–H2O. Org Lett 2015; 17:5144-7. [DOI: 10.1021/acs.orglett.5b02732] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Shicheng Shi
- Department
of Chemistry, Rutgers University, 73 Warren Street, Newark, New Jersey 07102, United States
| | - Michal Szostak
- Department
of Chemistry, Rutgers University, 73 Warren Street, Newark, New Jersey 07102, United States
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13
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Tureček F. Benchmarking Electronic Excitation Energies and Transitions in Peptide Radicals. J Phys Chem A 2015; 119:10101-11. [DOI: 10.1021/acs.jpca.5b06235] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- František Tureček
- Department of Chemistry, University of Washington, Bagley Hall,
Box 351700, Seattle, Washington 98195-1700, United States
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14
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Liu X, Wesdemiotis C. Electron transfer dissociation of doubly charged ions with different cationizing agents. EUROPEAN JOURNAL OF MASS SPECTROMETRY (CHICHESTER, ENGLAND) 2015; 21:713-723. [PMID: 26579927 DOI: 10.1255/ejms.1393] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Electron transfer dissociation (ETD) studies have been performed on a peptide and a synthetic polysaccharide doubly charged by different cationization agents. The ETD of protonated-sodiated bombesin gave rise to contiguous series of abundant c- and z-type ions that identified the complete sequence. ETD of the doubly protonated peptide produced a different fragment distribution, which also allowed for complete sequence coverage, but the relative intensities of some sequence ions were very small. Collisionally activated dissociation (CAD) of either precursor rendered limited sequence information. ETD of the sodiated-ammoniated pentamer of a starch-derived linear polysaccharide caused extensive fragmentation through cross-ring cleavages that revealed the possible position of a hydroxyethyl substituent on the saccharide ring. In contrast, ETD of the di-sodiated pentasaccharide did not produce a structure-revealing fragmentation pattern. On the other hand, CAD resulted in efficient glycosidic bond cleavages, either directly (from the sodiated-ammoniated precursor) or via multi-stage fragmentation (from the di-sodiated precursor), which indicated that hydroxyethylation occurs randomly at any saccharide repeat unit along the chain. Overall, the use of different cationizing agents complements the information available by using identical charge sites and opens or enhances ETD pathways that unveil valuable sequence or positional information.
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Affiliation(s)
- Xiumin Liu
- Department of Chemistry, The University of Akron, Akron, OH 44325, USA. Current address: Covance Inc., 3301 Kinsman Blvd., Madison, WI 53704, USA.
| | - Chrys Wesdemiotis
- Department of Chemistry, The University of Akron, Akron, OH 44325, USA.
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15
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Zhang R, Liu J, Yang H, Wang S, Zhang M, Bu Y. Computational insights into the charge relaying properties of β-turn peptides in protein charge transfers. Chemphyschem 2014; 16:436-46. [PMID: 25430869 DOI: 10.1002/cphc.201402657] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Indexed: 11/11/2022]
Abstract
Density functional theory calculations suggest that β-turn peptide segments can act as a novel dual-relay elements to facilitate long-range charge hopping transport in proteins, with the N terminus relaying electron hopping transfer and the C terminus relaying hole hopping migration. The electron- or hole-binding ability of such a β-turn is subject to the conformations of oligopeptides and lengths of its linking strands. On the one hand, strand extension at the C-terminal end of a β-turn considerably enhances the electron-binding of the β-turn N terminus, due to its unique electropositivity in the macro-dipole, but does not enhance hole-forming of the β-turn C terminus because of competition from other sites within the β-strand. On the other hand, strand extension at the N terminal end of the β-turn greatly enhances hole-binding of the β-turn C terminus, due to its distinct electronegativity in the macro-dipole, but does not considerably enhance electron-binding ability of the N terminus because of the shared responsibility of other sites in the β-strand. Thus, in the β-hairpin structures, electron- or hole-binding abilities of both termini of the β-turn motif degenerate compared with those of the two hook structures, due to the decreased macro-dipole polarity caused by the extending the two terminal strands. In general, the high polarity of a macro-dipole always plays a principal role in determining charge-relay properties through modifying the components and energies of the highest occupied and lowest unoccupied molecular orbitals of the β-turn motif, whereas local dipoles with low polarity only play a cooperative assisting role. Further exploration is needed to identify other factors that influence relay properties in these protein motifs.
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Affiliation(s)
- Ru Zhang
- Institute of Theoretical Chemistry, School of Chemistry and Chemical Engineering, Shandong University, Jinan, 250100 (P.R. China)
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16
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Marek A, Tureček F. Collision-induced dissociation of diazirine-labeled peptide ions. Evidence for Brønsted-acid assisted elimination of nitrogen. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2014; 25:778-789. [PMID: 24549894 DOI: 10.1007/s13361-014-0832-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Revised: 12/26/2013] [Accepted: 01/09/2014] [Indexed: 06/03/2023]
Abstract
Gas-phase dissociations were investigated for several peptide ions containing the Gly-Leu* N-terminal motif where Leu* was a modified norleucine residue containing the photolabile diazirine ring. Collisional activation of gas-phase peptide cations resulted in facile N₂ elimination that competed with backbone dissociations. A free lysine ammonium group can act as a Brønsted acid to facilitate N₂ elimination. This dissociation was accompanied by insertion of a lysine proton in the side chain of the photoleucine residue, as established by deuterium labeling and gas-phase sequencing of the products. Electron structure calculations were used to provide structures and energies of reactants, intermediates, and transition states for Gly-Leu*-Gly-Gly-Lys amide ions that were combined with RRKM calculations of unimolecular rate constants. The calculations indicated that Brønsted acid-catalyzed eliminations were kinetically preferred over direct loss of N₂ from the diazirine ring. Mechanisms are proposed to explain the proton-initiated reactions and discuss the reaction products. The non-catalyzed diazirine ring cleavage and N₂ loss is proposed as a thermometer dissociation for peptide ion dissociations.
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Affiliation(s)
- Aleš Marek
- Department of Chemistry, University of Washington, Bagley Hall, Seattle, WA, 98195-1700, USA
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17
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Tureček F. Renaissance of cation-radicals in mass spectrometry. Mass Spectrom (Tokyo) 2013; 2:S0003. [PMID: 24349922 PMCID: PMC3810458 DOI: 10.5702/massspectrometry.s0003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Accepted: 11/08/2012] [Indexed: 11/23/2022] Open
Abstract
This brief overview addresses the topic that was presented in the Thomson Medal Award session at the 19th International Mass Spectrometry Conference in Kyoto, Japan. Mass spectrometry of cation-radicals has enjoyed a remarkable renaissance thanks to the development of new methods for electron attachment to multiply charged peptide ions. The charge-reduced ions that are odd-electron species exhibit interesting reactivity that is useful for peptide and protein sequencing. The paper briefly reviews the fundamental aspects of the formation, energetics, and backbone dissociations of peptide cation-radicals.
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18
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Tan L, Xia Y. Gas-phase peptide sulfinyl radical ions: formation and unimolecular dissociation. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2012; 23:2011-2019. [PMID: 22911098 DOI: 10.1007/s13361-012-0465-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Revised: 07/27/2012] [Accepted: 07/31/2012] [Indexed: 06/01/2023]
Abstract
A variety of peptide sulfinyl radical (RSO•) ions with a well-defined radical site at the cysteine side chain were formed at atmospheric pressure (AP), sampled into a mass spectrometer, and investigated via collision-induced dissociation (CID). The radical ion formation was based on AP reactions between oxidative radicals and peptide ions containing single inter-chain disulfide bond or free thiol group generated from nanoelectrospray ionization (nanoESI). The radical induced reactions allowed large flexibility in forming peptide radical ions independent of ion polarity (protonated or deprotonated) or charge state (singly or multiply charged). More than 20 peptide sulfinyl radical ions in either positive or negative ion mode were subjected to low energy collisional activation on a triple-quadrupole/linear ion trap mass spectrometer. The competition between radical- and charge-directed fragmentation pathways was largely affected by the presence of mobile protons. For peptide sulfinyl radical ions with reduced proton mobility (i.e., singly protonated, containing basic amino acid residues), loss of 62 Da (CH(2)SO), a radical-initiated dissociation channel, was dominant. For systems with mobile protons, this channel was suppressed, while charge-directed amide bond cleavages were preferred. The polarity of charge was found to significantly alter the radical-initiated dissociation channels, which might be related to the difference in stability of the product ions in different ion charge polarities.
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Affiliation(s)
- Lei Tan
- Department of Chemistry, Purdue University, West Lafayette, IN 47907-2084, USA
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19
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Zimnicka M, Moss CL, Chung TW, Hui R, Tureček F. Tunable charge tags for electron-based methods of peptide sequencing: design and applications. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2012; 23:608-620. [PMID: 21952752 DOI: 10.1007/s13361-011-0184-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Revised: 05/24/2011] [Accepted: 05/24/2011] [Indexed: 05/31/2023]
Abstract
Charge tags using basic auxiliary functional groups 6-aminoquinolinylcarboxamido, 4-aminopyrimidyl-1-methylcarboxamido, 2-aminobenzoimidazolyl-1-methylcarboxamido, and the fixed-charge 4-(dimethylamino)pyridyl-1-carboxamido moiety are evaluated as to their properties in electron transfer dissociation mass spectra of arginine C-terminated peptides. The neutral tags have proton affinities that are competitive with those of amino acid residues in peptides. Charge reduction by electron transfer from fluoranthene anion-radicals results in peptide backbone dissociations that improve sequence coverage by providing extensive series of N-terminal c-type fragments without impeding the formation of C-terminal z fragments. Comparison of ETD mass spectra of free and tagged peptides allows one to resolve ambiguities in fragment ion assignment through mass shifts of c ions. Simple chemical procedures are reported for N-terminal tagging of Arg-containing tryptic peptides.
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Affiliation(s)
- Magdalena Zimnicka
- Department of Chemistry, University of Washington, Bagley Hall, Box 351700, Seattle, WA 98195-1700, USA
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20
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Li W, Zhang Z, Yang H, Wu X, Liu J, Bu Y. Trapping of excess electrons at the microhydrated protonated amino groups in proteins. J Chem Phys 2012; 136:105101. [DOI: 10.1063/1.3685606] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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21
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Moss CL, Liang W, Li X, Tureček F. The early life of a peptide cation-radical. Ground and excited-state trajectories of electron-based peptide dissociations during the first 330 femtoseconds. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2012; 23:446-459. [PMID: 22187160 DOI: 10.1007/s13361-011-0283-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Revised: 10/11/2011] [Accepted: 10/18/2011] [Indexed: 05/31/2023]
Abstract
We report a new approach to investigating the mechanisms of fast peptide cation-radical dissociations based on an analysis of time-resolved reaction progress by Ehrenfest dynamics, as applied to an Ala-Arg cation-radical model system. Calculations of stationary points on the ground electronic state that were carried out with effective CCSD(T)/6-311++G(3df,2p) could not explain the experimental branching ratios for loss of a hydrogen atom, ammonia, and N-C(α) bond dissociation in (AR + 2H)(+•). The Ehrenfest dynamics results indicate that the ground and low-lying excited electronic states of (AR + 2H)(+•) follow different reaction courses in the first 330 femtoseconds after electron attachment. The ground (X) state undergoes competing loss of N-terminal ammonia and isomerization to an aminoketyl radical intermediate that depend on the vibrational energy of the charge-reduced ion. The A and B excited states involve electron capture in the Arg guanidine and carboxyl groups and are non-reactive on the short time scale. The C state is dissociative and progresses to a fast loss of an H atom from the Arg guanidine group. Analogous results were obtained by using the B3LYP and CAM-B3LYP density functionals for the excited state dynamics and including the universal M06-2X functional for ground electronic state calculations. The results of this Ehrenfest dynamics study indicate that reaction pathway branching into the various dissociation channels occurs in the early stages of electron attachment and is primarily determined by the electronic states being accessed. This represents a new paradigm for the discussion of peptide dissociations in electron based methods of mass spectrometry.
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Affiliation(s)
- Christopher L Moss
- Department of Chemistry, University of Washington, Bagley Hall, Box 351700, Seattle, WA, USA
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22
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Afonso C, Tabet JC, Giorgi G, Tureček F. Gas-phase doubly charged complexes of cyclic peptides with copper in +1, +2 and +3 formal oxidation states: formation, structures and electron capture dissociation. JOURNAL OF MASS SPECTROMETRY : JMS 2012; 47:208-220. [PMID: 22359331 DOI: 10.1002/jms.2956] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Copper complexes with a cyclic D-His-β-Ala-L-His-L-Lys and all-L-His-β-Ala-His-Lys peptides were generated by electrospray which were doubly charged ions that had different formal oxidation states of Cu(I), Cu(II) and Cu(III) and different protonation states of the peptide ligands. Electron capture dissociation showed no substantial differences between the D-His and L-His complexes. All complexes underwent peptide cross-ring cleavages upon electron capture. The modes of ring cleavage depended on the formal oxidation state of the Cu ion and peptide protonation. Density functional theory (DFT) calculations, using the B3LYP with an effective core potential at Cu and M06-2X functionals, identified several precursor ion structures in which the Cu ion was threecoordinated to pentacoordinated by the His and Lys side-chain groups and the peptide amide or enolimine groups. The electronic structure of the formally Cu(III) complexes pointed to an effective Cu(I) oxidation state with the other charge residing in the peptide ligand. The relative energies of isomeric complexes of the [Cu(c-HAHK + H)](2+) and [Cu(c-HAHK - H)](2+) type with closed electronic shells followed similar orders when treated by the B3LYP and M06-2X functionals. Large differences between relative energies calculated by these methods were obtained for open-shell complexes of the [Cu(c-HAHK)](2+) type. Charge reduction resulted in lowering the coordination numbers for some Cu complexes that depended on the singlet or triplet spin state being formed. For [Cu(c-HAHK - H)](2+) complexes, solution H/D exchange involved only the N-H protons, resulting in the exchange of up to seven protons, as established by ultra-high mass resolution measurements. Contrasting the experiments, DFT calculations found the lowest energy structures for the gas-phase ions that were deprotonated at the peptide C(α) positions.
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Affiliation(s)
- Carlos Afonso
- Institut Parisien de Chimie Moléculaire, CNRS-UMR 7201, Université Pierre et Marie Curie-Paris 6, 4 place Jussieu, Paris, France
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23
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Chomicz L, Rak J, Paneth P, Sevilla M, Ko YJ, Wang H, Bowen KH. Valence anions of N-acetylproline in the gas phase: computational and anion photoelectron spectroscopic studies. J Chem Phys 2011; 135:114301. [PMID: 21950856 PMCID: PMC3298562 DOI: 10.1063/1.3625957] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Accepted: 07/28/2011] [Indexed: 11/14/2022] Open
Abstract
We report the photoelectron spectrum of anionic N-acetylproline, (N-AcPro)(-), measured with 3.49 eV photons. This spectrum, which consists of a band centered at an electron binding energy of 1.4 eV and a higher energy spectral tail, confirms that N-acetylproline forms a valence anion in the gas phase. The neutrals and anions of N-AcPro were also studied computationally at the B3LYP∕6-31++G(d,p) level. Based on the calculations, we conclude that the photoelectron spectrum is due to anions which originated from proton transfer induced by electron attachment to the π* orbital localized at the acetyl group of N-AcPro. We also characterized the energetics of reaction paths leading to pyrrolidine ring opening in the anionic N-AcPro. These data suggest that electron induced decomposition of peptides/proteins comprising proline strongly depends on the presence of proton donors in the close vicinity to the proline residue.
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Affiliation(s)
- Lidia Chomicz
- Department of Chemistry, University of Gdańsk, Sobieskiego 18, 80-952 Gdańsk, Poland
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24
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Moss CL, Chung TW, Wyer JA, Nielsen SB, Hvelplund P, Tureček F. Dipole-guided electron capture causes abnormal dissociations of phosphorylated pentapeptides. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2011; 22:731-51. [PMID: 21472611 DOI: 10.1007/s13361-011-0083-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2010] [Revised: 01/06/2011] [Accepted: 01/08/2011] [Indexed: 05/25/2023]
Abstract
Electron transfer and capture mass spectra of a series of doubly charged ions that were phosphorylated pentapeptides of a tryptic type (pS,A,A,A,R) showed conspicuous differences in dissociations of charge-reduced ions. Electron transfer from both gaseous cesium atoms at 100 keV kinetic energies and fluoranthene anion radicals in an ion trap resulted in the loss of a hydrogen atom, ammonia, and backbone cleavages forming complete series of sequence z ions. Elimination of phosphoric acid was negligible. In contrast, capture of low-energy electrons by doubly charged ions in a Penning ion trap induced loss of a hydrogen atom followed by elimination of phosphoric acid as the dominant dissociation channel. Backbone dissociations of charge-reduced ions also occurred but were accompanied by extensive fragmentation of the primary products. z-Ions that were terminated with a deaminated phosphoserine radical competitively eliminated phosphoric acid and H(2)PO(4) radicals. A mechanism is proposed for this novel dissociation on the basis of a computational analysis of reaction pathways and transition states. Electronic structure theory calculations in combination with extensive molecular dynamics mapping of the potential energy surface provided structures for the precursor phosphopeptide dications. Electron attachment produces a multitude of low lying electronic states in charge-reduced ions that determine their reactivity in backbone dissociations and H- atom loss. The predominant loss of H atoms in ECD is explained by a distortion of the Rydberg orbital space by the strong dipolar field of the peptide dication framework. The dipolar field steers the incoming electron to preferentially attach to the positively charged arginine side chain to form guanidinium radicals and trigger their dissociations.
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Affiliation(s)
- Christopher L Moss
- Department of Chemistry, University of Washington, Bagley Hall, Box 351700, Seattle, WA 98195-1700, USA
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25
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Sargaeva NP, Lin C, O’Connor PB. Unusual fragmentation of β-linked peptides by ExD tandem mass spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2011; 22:480-91. [PMID: 21472566 PMCID: PMC4361814 DOI: 10.1007/s13361-010-0049-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Revised: 11/18/2010] [Accepted: 11/18/2010] [Indexed: 05/11/2023]
Abstract
Ion-electron reaction based fragmentation methods (ExD) in tandem mass spectrometry (MS), such as electron capture dissociation (ECD) and electron transfer dissociation (ETD) represent a powerful tool for biological analysis. ExD methods have been used to differentiate the presence of the isoaspartate (isoAsp) from the aspartate (Asp) in peptides and proteins. IsoAsp is a β(3)-type amino acid that has an additional methylene group in the backbone, forming a C(α)-C(β) bond within the polypeptide chain. Cleavage of this bond provides specific fragments that allow differentiation of the isomers. The presence of a C(α)-C(β) bond within the backbone is unique to β-amino acids, suggesting a similar application of ExD toward the analysis of peptides containing other β-type amino acids. In the current study, ECD and ETD analysis of several β-amino acid containing peptides was performed. It was found that N-C(β) and C(α)-C(β) bond cleavages were rare, providing few c and z• type fragments, which was attributed to the instability of the C(β) radical. Instead, the electron capture resulted primarily in the formation of a• and y fragments, representing an alternative fragmentation pathway, likely initiated by the electron capture at a backbone amide nitrogen protonation site within the β amino acid residues.
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Affiliation(s)
- Nadezda P. Sargaeva
- Mass Spectrometry Resource, Department of Biochemistry, Boston University School of Medicine, 670 Albany Street, R504, Boston, Massachusetts 02118
| | - Cheng Lin
- Mass Spectrometry Resource, Department of Biochemistry, Boston University School of Medicine, 670 Albany Street, R504, Boston, Massachusetts 02118
| | - Peter B. O’Connor
- Mass Spectrometry Resource, Department of Biochemistry, Boston University School of Medicine, 670 Albany Street, R504, Boston, Massachusetts 02118
- Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK
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26
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Tanabe T, Noda K, Miyagi S, Kurita N, Tanaka S, Setzler J, Wenzel W, Starikov EB, Cuniberti G. Resonant neutral particle emission in collisions of electrons with protonated peptides with disulfide bonds at high energies. Chem Phys Lett 2011. [DOI: 10.1016/j.cplett.2011.01.058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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27
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Chung TW, Moss CL, Zimnicka M, Johnson RS, Moritz RL, Tureček F. Electron-capture and -transfer dissociation of peptides tagged with tunable fixed-charge groups: structures and dissociation energetics. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2011; 22:13-30. [PMID: 21472540 DOI: 10.1007/s13361-010-0012-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2010] [Revised: 09/26/2010] [Accepted: 10/11/2010] [Indexed: 05/30/2023]
Abstract
Pyridiniummethylcarbonyl moieties that were previously designed on the basis of electronic structure analysis are now utilized as fixed-charge tags with tunable electronic properties to be used for N-terminal peptide derivatization and sequencing by electron-transfer dissociation. Dipeptides AK and KA were derivatized at the peptide N-terminus with 4-dimethylaminopyridinium-N-acetyl (DMAP-ac) and pyridinium-N-acetyl (pyrid-ac) tags of increasing intrinsic recombination energies. Upon the capture of a free electron or electron transfer from fluoranthene anions, (DMAP-ac-AK+H)(2+), (DMAP-ac-KA+H)(2+), (pyrid-ac-AK+H)(2+) and (pyrid-ac-KA+H)(2+) ions, as well as underivatized (AK+2H)(2+), completely dissociated. The fixed-charge tags steered the dissociation upon electron transfer to form abundant backbone N-C(α) bond cleavages, whereas the underivatized peptide mainly underwent H-atom and side-chain losses. Precursor ion structures for the tagged peptides were analyzed by an exhaustive conformational search combined with B3LYP/6-31+G(d,p) geometry optimization and single-point energy calculations in order to select the global energy minima. Structures, relative energies, transition states, ion-molecule complexes, and dissociation products were identified for several charge-reduced species from the tagged peptides. The electronic properties of the charge tags and their interactions with the peptide moieties are discussed. Electrospray ionization and electron-transfer dissociation of larger peptides are illustrated with a DMAP-tagged pentapeptide.
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Affiliation(s)
- Thomas W Chung
- Department of Chemistry, University of Washington, Bagley Hall, Box 351700, Seattle, WA 98195-1700, USA
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28
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Turecek F, Chung TW, Moss CL, Wyer JA, Ehlerding A, Holm AIS, Zettergren H, Nielsen SB, Hvelplund P, Chamot-Rooke J, Bythell B, Paizs B. The histidine effect. Electron transfer and capture cause different dissociations and rearrangements of histidine peptide cation-radicals. J Am Chem Soc 2010; 132:10728-40. [PMID: 20681705 DOI: 10.1021/ja907808h] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Electron-transfer and -capture dissociations of doubly protonated peptides gave dramatically different product ions for a series of histidine-containing pentapeptides of both non-tryptic (AAHAL, AHAAL, AHADL, AHDAL) and tryptic (AAAHK, AAHAK, AHAAK, HAAAK, AAAHR, AAHAR, AHAAR, HAAAR) type. Electron transfer from gaseous Cs atoms and fluoranthene anions triggered backbone dissociations of all four N-C(alpha) bonds in the peptide ions in addition to loss of H and NH(3). Substantial fractions of charge-reduced cation-radicals did not dissociate on an experimental time scale ranging from 10(-6) to 10(-1) s. Multistage tandem mass spectrometric (MS(n)) experiments indicated that the non-dissociating cation-radicals had undergone rearrangements. These were explained as being due to proton migrations from N-terminal ammonium and COOH groups to the C-2' position of the reduced His ring, resulting in substantial radical stabilization. Ab initio calculations revealed that the charge-reduced cation-radicals can exist as low-energy zwitterionic amide pi* states which were local energy minima. These states underwent facile exothermic proton migrations to form aminoketyl radical intermediates, whereas direct N-C(alpha) bond cleavage in zwitterions was disfavored. RRKM analysis indicated that backbone N-C(alpha) bond cleavages did not occur competitively from a single charge-reduced precursor. Rather, these bond cleavages proceeded from distinct intermediates which originated from different electronic states accessed by electron transfer. In stark contrast to electron transfer, capture of a free electron by the peptide ions mainly induced radical dissociations of the charge-carrying side chains and loss of a hydrogen atom followed by standard backbone dissociations of even-electron ions. The differences in dissociation are explained by different electronic states being accessed upon electron transfer and capture.
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Affiliation(s)
- Frantisek Turecek
- Department of Chemistry, Bagley Hall, Box 351700, University of Washington, Seattle, Washington 98195-1700, USA.
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29
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Tureček F. Electron predators are hydrogen atom traps. Effects of aryl groups on N-C(α) bond dissociations of peptide radicals. JOURNAL OF MASS SPECTROMETRY : JMS 2010; 45:1280-1290. [PMID: 20812369 DOI: 10.1002/jms.1807] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2010] [Accepted: 08/05/2010] [Indexed: 05/29/2023]
Abstract
Effects of substituted aryl groups on dissociations of peptide aminoketyl radicals were studied computationally for model tetrapeptide intermediates GXD(•) G where X was a cysteine residue that was derivatized by S-(3-nitrobenzyl), S-(3-cyanobenzyl), S-(3,5-dicyanobenzyl), S-(2,3,4,5,6-pentafluorobenzyl), and S-benzyl groups. The aminoketyl radical was placed within the Asp amide group. Aminoketyl radicals having the S-(3-nitrobenzyl) group were found to undergo spontaneous and highly exothermic migration of the hydroxyl hydrogen atom onto the nitro group in conformers allowing interaction between these groups. Competing reaction channels were investigated for aminoketyl radicals having the S-(3-cyanobenzyl) and S-(3,5-dicyanobenzyl) groups, e.g. H-atom migration to the C and N atoms of the C≡N group, migration to the C-4 position of the phenyl ring, and dissociation of the radical-activated NC(α) bond between the Asp and Gly residues. RRKM kinetic analysis on the combined B3LYP and ROMP2/6-311++G(2d,p) potential energy surface indicated > 99% H-atom transfer to the C≡N group forming a stable iminyl intermediate. The NC(α) bond dissociation was negligible. In contrast, peptides with the S-(2,3,4,5,6-pentafluorobenzyl) and S-benzyl groups showed preferential NC(α) bond dissociation that outcompeted H-atom migration to the C-4 position and fluorine substituents in the phenyl ring. These computational results are used to suggest an alternative mechanism for the quenching effect on electron-based peptide backbone dissociations of benzyl groups with electron-withdrawing substitutents, as reported recently.
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Affiliation(s)
- František Tureček
- Department of Chemistry, Bagley Hall, Box 351700, University of Washington, Seattle, WA 98195-1700, USA.
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30
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Turecek F, Jones JW, Holm AIS, Panja S, Nielsen SB, Hvelplund P. Transition metals as electron traps. I. Structures, energetics, electron capture, and electron-transfer-induced dissociations of ternary copper-peptide complexes in the gas phase. JOURNAL OF MASS SPECTROMETRY : JMS 2009; 44:707-724. [PMID: 19132713 DOI: 10.1002/jms.1546] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Electron-induced dissociations of gas-phase ternary copper-2,2'-bipyridine complexes of Gly-Gly-Gly and Gly-Gly-Leu were studied on a time scale ranging from 130 ns to several milliseconds using a combination of charge-reversal ((+)CR(-)) and electron-capture-induced dissociation (ECID) measured on a beam instrument and electron capture dissociation (ECD) measured in a Penning trap. Charge-reduced intermediates were observed on the short time scale in the (+)CR(-) and ECID experiments but not in ECD. Ion dissociations following electron transfer or capture mostly occurred by competitive bpy or peptide ligand loss, whereas peptide backbone fragmentations were suppressed in the presence of the ligated metal ion. Extensive electron structure theory calculations using density functional theory and large basis sets provided optimized structures and energies for the precursor ions, charge-reduced intermediates, and dissociation products. The Cu complexes underwent substantial structure changes upon electron capture. Cu was calculated to be pentacoordinated in the most stable singly charged complexes of the [Cu(peptide-H)bpy](+*) type where it carried a approximately +1 atomic charge. Cu coordination in charge-reduced [Cu(peptide-H)bpy] intermediates depended on the spin state. The themodynamically more stable singlet states had tricoordinated Cu, whereas triplet states had a tetracoordinated Cu. Cu was tricoordinated in stable [Cu(peptide-H)bpy](-*) products of electron transfer. [Cu(peptide)bpy](2+*) complexes contained the peptide ligand in a zwitterionic form while Cu was tetracoordinated. Upon electron capture, Cu was tri- or tetracoordinated in the [Cu(peptide)bpy](+) charge-reduced analogs and the peptide ligands underwent prototropic isomerization to canonical forms. The role of excited singlet and triplet electronic states is assessed.
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Affiliation(s)
- Frantisek Turecek
- Department of Chemistry, Bagley Hall, University of Washington, Seattle, WA 98195-1700, USA.
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Sohn CH, Chung CK, Yin S, Ramachandran P, Loo JA, Beauchamp JL. Probing the mechanism of electron capture and electron transfer dissociation using tags with variable electron affinity. J Am Chem Soc 2009; 131:5444-59. [PMID: 19331417 PMCID: PMC2765496 DOI: 10.1021/ja806534r] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Electron capture dissociation (ECD) and electron transfer dissociation (ETD) of doubly protonated electron affinity (EA)-tuned peptides were studied to further illuminate the mechanism of these processes. The model peptide FQpSEEQQQTEDELQDK, containing a phosphoserine residue, was converted to EA-tuned peptides via beta-elimination and Michael addition of various thiol compounds. These include propanyl, benzyl, 4-cyanobenzyl, perfluorobenzyl, 3,5-dicyanobenzyl, 3-nitrobenzyl, and 3,5-dinitrobenzyl structural moieties, having a range of EA from -1.15 to +1.65 eV, excluding the propanyl group. Typical ECD or ETD backbone fragmentations are completely inhibited in peptides with substituent tags having EA over 1.00 eV, which are referred to as electron predators in this work. Nearly identical rates of electron capture by the dications substituted by the benzyl (EA = -1.15 eV) and 3-nitrobenzyl (EA = 1.00 eV) moieties are observed, which indicates the similarity of electron capture cross sections for the two derivatized peptides. This observation leads to the inference that electron capture kinetics are governed by the long-range electron-dication interaction and are not affected by side chain derivatives with positive EA. Once an electron is captured to high-n Rydberg states, however, through-space or through-bond electron transfer to the EA-tuning tags or low-n Rydberg states via potential curve crossing occurs in competition with transfer to the amide pi* orbital. The energetics of these processes are evaluated using time-dependent density functional theory with a series of reduced model systems. The intramolecular electron transfer process is modulated by structure-dependent hydrogen bonds and is heavily affected by the presence and type of electron-withdrawing groups in the EA-tuning tag. The anion radicals formed by electron predators have high proton affinities (approximately 1400 kJ/mol for the 3-nitrobenzyl anion radical) in comparison to other basic sites in the model peptide dication, facilitating exothermic proton transfer from one of the two sites of protonation. This interrupts the normal sequence of events in ECD or ETD, leading to backbone fragmentation by forming a stable radical intermediate. The implications which these results have for previously proposed ECD and ETD mechanisms are discussed.
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Affiliation(s)
- Chang Ho Sohn
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125
| | - Cheol K. Chung
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125
| | - Sheng Yin
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095
| | - Prasanna Ramachandran
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095
| | - Joseph A. Loo
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095
| | - J. L. Beauchamp
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125
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Hao C, Turecek F. Host-guest hydrogen atom transfer induced by electron capture. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2009; 20:639-651. [PMID: 19185509 DOI: 10.1016/j.jasms.2008.12.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2008] [Revised: 12/01/2008] [Accepted: 12/01/2008] [Indexed: 05/27/2023]
Abstract
1,n-Alkanediammonium cations in noncovalent complexes with two dibenzo-18-crown-6-ether (DBCE) ligands undergo an unusual intramolecular tandem hydrogen atom and proton transfer to the crown ether ligand upon charge reduction by electron capture. Deuterium labeling established that both migrating hydrogens originated from the ammonium groups. The double hydrogen transfer was found to depend on the length of the alkane chain connecting the ammonium groups. Ab initio calculations provided structures for select alkanediammonium.dibenzo-18-crown-6-ether complexes and dissociation products. This first observation of an intra-complex hydrogen transfer is explained by the unusual electronic properties of the complexes and the substantial hydrogen atom affinity of the aromatic rings in the crown ligand.
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Affiliation(s)
- Changtong Hao
- Department of Chemistry, University of Washington, Seattle, Washington, USA
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33
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Panja S, Nielsen SB, Hvelplund P, Turecek F. Inverse hydrogen migration in arginine-containing peptide ions upon electron transfer. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2008; 19:1726-1742. [PMID: 18799322 DOI: 10.1016/j.jasms.2008.08.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2008] [Revised: 08/01/2008] [Accepted: 08/04/2008] [Indexed: 05/26/2023]
Abstract
Collisional electron transfer from gaseous Cs atoms was studied for singly and doubly protonated peptides Gly-Arg (GR) and Ala-Arg (AR) at 50- and 100-keV kinetic energies. Singly protonated GR and AR were discharged to radicals that in part rearranged by migration of a C(alpha) hydrogen atom onto the guanidine group. The C(alpha)-radical isomers formed were detected as stable anions following transfer of a second electron. In addition to the stabilizing rearrangements, the radicals underwent side-chain and backbone dissociations. The latter formed z fragments that were detected as the corresponding anions. Analysis of the (GR + H)(.) radical potential energy surface using electronic structure theory in combination with Rice-Ramsperger-Kassel-Marcus calculations of rate constants indicated that the arginine C(alpha) hydrogen atom was likely to be transferred to the arginine side-chain on the experimental timescale of <or=200 ns. Transfer of the Gly C(alpha)H was calculated to have a higher transition-state energy and was not kinetically competitive. Collisional electron transfer to doubly protonated GR and AR resulted in complete dissociation of (GR + 2H)(+.) and (AR + 2H)(+.) ions by loss of H, ammonia, and NC(alpha) bond cleavage. Electronic structure theory analysis of (GR + 2H)(+.) indicated the presence of multiple conformers and electronic states that differed in reactivity and steered the dissociations to distinct channels. Electron attachment to (GR + 2H)(2+) resulted in the formation of closely spaced electronic states of (GR + 2H)(+.) in which the electron density was delocalized over the guanidinium, ammonium, amide, and carboxyl groups. The different behavior of (GR + H)(.) and (GR + 2H)(+.) is explained by the different timescales for dissociation and different internal energies acquired upon electron transfer.
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Affiliation(s)
- Subhasis Panja
- Department of Physics and Astronomy, University of Aarhus, Denmark
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Chung TW, Turecek F. Electronic properties of charge-tagged peptides upon electron capture. EUROPEAN JOURNAL OF MASS SPECTROMETRY (CHICHESTER, ENGLAND) 2008; 14:367-378. [PMID: 19136725 DOI: 10.1255/ejms.954] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We report a computational study of Ala-Lys (AK) and Lys-Ala (KA) dipeptide ions furnished with fixed-charged pyridinium groups that were attached by amide linkers to the N-terminal amino groups. Cation-radicals from one-electron reduction of the doubly charged AK and KA peptide conjugates showed various extents of unpaired electron density being delocalized between the pyridine and peptide moieties. The delocalization depended on the local recombination energies (RE(loc)) of the charged groups. The RE(loc) of the pyridine moieties were modified by introducing electron-donating substituents (CH(3), OCH(3), and N(CH(3))(2)). The RE(loc) of the peptide moieties were found to depend on the peptide conformation and internal solvation of the Lys ammonium groups. Substantial electron delocalization was found for combinations of pyridine substituents and peptide conformers with closely matched RE(loc), such as 4-dimethylamino-pyridine and internally solvated Lys ammonium or unsubstituted pyridine and free (unsolvated) Lys ammonium. The dissociation (DeltaH(diss)) and transition state energies (E(TS)) for the loss of the pyridine ring from the conjugates were found to be DeltaH(diss) = 34-36 kJ mol(-1) and E(TS) = 67-69 kJ mol(-1) for the unsubstituted pyridine moieties, but did not depend much on the peptide sequence.
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Affiliation(s)
- Thomas W Chung
- Department of Chemistry, Bagley Hall, Box 351700, University of Washington, Seattle, WA 98195-1700, USA
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35
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Affiliation(s)
- My Hang V Huynh
- DE-1: High Explosive Science and Technology Group, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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