1
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Wan J, Vlk M, Nytka M, Vu TNK, Lemr K, Tureček F. Photochemical and Collision-Induced Cross-Linking of Lys, Arg, and His to Nitrile Imines in Peptide Conjugate Ions in the Gas Phase. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2025; 36:209-220. [PMID: 39690835 DOI: 10.1021/jasms.4c00438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2024]
Abstract
We report a study of internal covalent cross-linking with photolytically generated diarylnitrile imines of N-terminal arginine, lysine, and histidine residues in peptide conjugates. Conjugates in which a 4-(2-phenyltetrazol-5-yl)benzoyl group was attached to C-terminal lysine, that we call RAAA-tet-K, KAAA-tet-K, and HAAA-tet-K, were ionized by electrospray and subjected to UV photodissociation (UVPD) at 213 nm. UVPD triggered loss of N2 and proceeded by covalent cross-linking to nitrile imine intermediates that involved the side chains of N-terminal arginine, lysine, and histidine, as well as the peptide amide groups. Cross-linking yields were determined from UVPD-MS2 measurements as 67%, 66%, and 84% for RAAA-tet-K, KAAA-tet-K, and HAAA-tet-K ions, respectively. CID-MS3 of the denitrogenated ion intermediates from RAAA-tet-K, KAAA-tet-K, and HAAA-tet-K indicated overall cross-linking yields of 80%, 89%, and 80%, respectively. The nature of the cross-linking reactions and cross-link structures were investigated for RAAA-tet-K by high-resolution cyclic ion mobility mass spectrometry that identified precursor ion conformers and multiple dissociation products. All sequences were subjected to conformational analysis by Born-Oppenheimer molecular dynamics, and energy analysis by density functional theory calculations with M06-2X/def2qzvpp that provided relative and dissociation energies for several cross-link structural types. The cross-linking reactions were substantially exothermic, driving the efficient conversion of nitrile-imine intermediates to cyclic products. The principal steps in covalent cross-linking involved proton transfer onto the nitrile imine group accompanied by nucleophilic attack by the peptide side-chain and amide groups. Blocking the proton transfer and nucleophile resulted in a loss of cross-linking abilities.
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Affiliation(s)
- Jiahao Wan
- Department of Chemistry, Bagley Hall, Box 351700, University of Washington, Seattle, Washington 98195-1700, United States
| | - Mikuláš Vlk
- Department of Chemistry, Bagley Hall, Box 351700, University of Washington, Seattle, Washington 98195-1700, United States
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Prague 16610, Czech Republic
- Department of Analytical Chemistry, Faculty of Science, Charles University, Prague 12800, Czech Republic
| | - Marianna Nytka
- Department of Analytical Chemistry, Faculty of Science, Palacký University, Olomouc 77900, Czech Republic
| | - Tuan Ngoc Kim Vu
- Department of Chemistry, Bagley Hall, Box 351700, University of Washington, Seattle, Washington 98195-1700, United States
| | - Karel Lemr
- Department of Analytical Chemistry, Faculty of Science, Palacký University, Olomouc 77900, Czech Republic
- Institute of Microbiology of the Czech Academy of Sciences, Prague 14220, Czech Republic
| | - František Tureček
- Department of Chemistry, Bagley Hall, Box 351700, University of Washington, Seattle, Washington 98195-1700, United States
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2
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Moppel I, Elliott B, Chen S. Intermolecular hydrogen bonding behavior of amino acid radical cations. Org Biomol Chem 2024; 22:3966-3978. [PMID: 38690804 DOI: 10.1039/d4ob00301b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2024]
Abstract
Amino acid and peptide radicals are of broad interest due to their roles in biochemical oxidative damage, pathogenesis and protein radical catalysis, among others. Using density functional theory (DFT) calculations at the ωB97X-D/def2-QZVPPD//ωB97X-D/def2-TZVPP level of theory, we systematically investigated the hydrogen bonding between water and fourteen α-amino acids (Ala, Asn, Cys, Gln, Gly, His, Met, Phe, Pro, Sel, Ser, Thr, Trp, and Tyr) in both neutral and radical cation forms. For all amino acids surveyed, stronger hydrogen-bonding interactions with water were observed upon single-electron oxidation, with the greatest increases in hydrogen-bonding strength occurring in Gly, Ala and His. We demonstrate that the side chain has a significant impact on the most favorable hydrogen-bonding modes experienced by amino acid radical cations. Our computations also explored the fragmentation of amino acid radical cations through the loss of a COOH radical facilitated by hydrogen bonding. The most favorable pathways provided stabilization of the resulting cationic fragments through hydrogen bonding, resulting in more favorable thermodynamics for the fragmentation process. These results indicate that non-covalent interactions with the environment have a profound impact on the structure and chemical fate of oxidized amino acids.
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Affiliation(s)
- Isabella Moppel
- Department of Chemistry and Biochemistry, Oberlin College, Oberlin, OH 44074, USA.
| | - BarbaraAnn Elliott
- Department of Chemistry and Biochemistry, Oberlin College, Oberlin, OH 44074, USA.
| | - Shuming Chen
- Department of Chemistry and Biochemistry, Oberlin College, Oberlin, OH 44074, USA.
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3
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Tureček F. UV-vis spectroscopy of gas-phase ions. MASS SPECTROMETRY REVIEWS 2023; 42:206-226. [PMID: 34392556 DOI: 10.1002/mas.21726] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 06/07/2021] [Accepted: 06/08/2021] [Indexed: 06/13/2023]
Abstract
Photodissociation action spectroscopy has made a great progress in expanding investigations of gas-phase ion structures. This review deals with aspects of gas-phase ion electronic excitations that result in wavelength-dependent dissociation and light emission via fluorescence, chiefly covering the ultraviolet and visible regions of the spectrum. The principles are briefly outlined and a few examples of instrumentation are presented. The main thrust of the review is to collect and selectively present applications of UV-vis action spectroscopy to studies of stable gas-phase ion structures and combinations of spectroscopy with ion mobility, collision-induced dissociation, and ion-ion reactions leading to the generation of reactive intermediates and electronic energy transfer.
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Affiliation(s)
- František Tureček
- Department of Chemistry, University of Washington, Seattle, Washington, USA
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4
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Liu Y, Ma C, Leonen CJA, Chatterjee C, Nováková G, Marek A, Tureček F. Tackling a Curious Case: Generation of Charge-Tagged Guanosine Radicals by Gas-Phase Electron Transfer and Their Characterization by UV-vis Photodissociation Action Spectroscopy and Theory. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2021; 32:772-785. [PMID: 33567214 PMCID: PMC8579407 DOI: 10.1021/jasms.0c00459] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We report the generation of gas-phase riboguanosine radicals that were tagged at ribose with a fixed-charge 6-(trimethylammonium)hexane-1-aminocarbonyl group. The radical generation relied on electron transfer from fluoranthene anion to noncovalent dibenzocrown-ether dication complexes which formed nucleoside cation radicals upon one-electron reduction and crown-ether ligand loss. The cation radicals were characterized by collision-induced dissociation (CID), photodissociation (UVPD), and UV-vis action spectroscopy. Identification of charge-tagged guanosine radicals was challenging because of spontaneous dissociations by loss of a hydrogen atom and guanine that occurred upon storing the ions in the ion trap without further excitation. The loss of H proceeded from an exchangeable position on N-7 in guanine that was established by deuterium labeling and was the lowest energy dissociation of the guanosine radicals according to transition-state energy calculations. Rate constant measurements revealed an inverse isotope effect on the loss of either hydrogen or deuterium with rate constants kH = 0.25-0.26 s-1 and kD = 0.39-0.54 s-1. We used time-dependent density functional theory calculations, including thermal vibronic effects, to predict the absorption spectra of several protomeric radical isomers. The calculated spectra of low-energy N-7-H guanine-radical tautomers closely matched the action spectra. Transition-state-theory calculations of the rate constants for the loss of H-7 and guanine agreed with the experimental rate constants for a narrow range of ion effective temperatures. Our calculations suggest that the observed inverse isotope effect does not arise from the isotope-dependent differences in the transition-state energies. Instead, it may be caused by the dynamics of post-transition-state complexes preceding the product separation.
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Affiliation(s)
- Yue Liu
- Department of Chemistry, Bagley Hall, Box 351700, University of Washington, Seattle, Washington 98195-1700, United States
| | - Congcong Ma
- Department of Chemistry, Bagley Hall, Box 351700, University of Washington, Seattle, Washington 98195-1700, United States
| | - Calvin J A Leonen
- Department of Chemistry, Bagley Hall, Box 351700, University of Washington, Seattle, Washington 98195-1700, United States
| | - Champak Chatterjee
- Department of Chemistry, Bagley Hall, Box 351700, University of Washington, Seattle, Washington 98195-1700, United States
| | - Gabriela Nováková
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, 16610 Prague 6, Czech Republic
| | - Aleš Marek
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, 16610 Prague 6, Czech Republic
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5
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Kempkes LJ, Martens J, Berden G, Houthuijs KJ, Oomens J. Investigation of the position of the radical in z3-ions resulting from electron transfer dissociation using infrared ion spectroscopy. Faraday Discuss 2019; 217:434-452. [DOI: 10.1039/c8fd00202a] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The molecular structures of six open-shell z3-ions resulting from electron transfer dissociation mass spectrometry (ETD MS) were investigated using infrared ion spectroscopy in combination with density functional theory and molecular mechanics/molecular dynamics calculations.
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Affiliation(s)
| | - Jonathan Martens
- Radboud University
- FELIX Laboratory
- 6525 ED Nijmegen
- The Netherlands
| | - Giel Berden
- Radboud University
- FELIX Laboratory
- 6525 ED Nijmegen
- The Netherlands
| | - Kas J. Houthuijs
- Radboud University
- FELIX Laboratory
- 6525 ED Nijmegen
- The Netherlands
| | - Jos Oomens
- Radboud University
- FELIX Laboratory
- 6525 ED Nijmegen
- The Netherlands
- Van’t Hoff Institute for Molecular Sciences
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6
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Kempkes LJM, Martens J, Berden G, Oomens J. w-Type ions formed by electron transfer dissociation of Cys-containing peptides investigated by infrared ion spectroscopy. JOURNAL OF MASS SPECTROMETRY : JMS 2018; 53:1207-1213. [PMID: 30281881 PMCID: PMC6283004 DOI: 10.1002/jms.4298] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2018] [Revised: 08/24/2018] [Accepted: 09/26/2018] [Indexed: 06/08/2023]
Abstract
In mass spectrometry-based peptide sequencing, electron transfer dissociation (ETD) and electron capture dissociation (ECD) have become well-established fragmentation methods complementary to collision-induced dissociation. The dominant fragmentation pathways during ETD and ECD primarily involve the formation of c- and z• -type ions by cleavage of the peptide backbone at the N─Cα bond, although neutral losses from amino acid side chains have also been observed. Residue-specific neutral side chain losses provide useful information when conducting database searching and de novo sequencing. Here, we use a combination of infrared ion spectroscopy and quantum-chemical calculations to assign the structures of two ETD-generated w-type fragment ions. These ions are spontaneously formed from ETD-generated z• -type fragments by neutral loss of 33 Da in peptides containing a cysteine residue. Analysis of the infrared ion spectra confirms that these z• -ions expel a thiol radical (SH• ) and that a vinyl C═C group is formed at the cleavage site. z• -type fragments containing a Cys residue but not at the cleavage site do not spontaneously expel a thiol radical, but only upon additional collisional activation after ETD.
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Affiliation(s)
- Lisanne J. M. Kempkes
- Radboud University, Institute for Molecules and Materials, FELIX LaboratoryNijmegenThe Netherlands
| | - Jonathan Martens
- Radboud University, Institute for Molecules and Materials, FELIX LaboratoryNijmegenThe Netherlands
| | - Giel Berden
- Radboud University, Institute for Molecules and Materials, FELIX LaboratoryNijmegenThe Netherlands
| | - Jos Oomens
- Radboud University, Institute for Molecules and Materials, FELIX LaboratoryNijmegenThe Netherlands
- Van't Hoff Institute for Molecular SciencesUniversity of AmsterdamAmsterdamThe Netherlands
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7
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Liu Y, Korn JA, Dang A, Tureček F. Hydrogen-Rich Cation Radicals of DNA Dinucleotides: Generation and Structure Elucidation by UV-Vis Action Spectroscopy. J Phys Chem B 2018; 122:9665-9680. [PMID: 30269486 DOI: 10.1021/acs.jpcb.8b07925] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Hydrogen-rich DNA dinucleotide cation radicals (dGG + 2H)+•, (dCG + 2H)+•, and (dGC + 2H)+• represent transient species comprising protonated and hydrogen atom adducted nucleobase rings that serve as models for proton and radical migrations in ionized DNA. These DNA cation radicals were generated in the gas phase by electron-transfer dissociation of dinucleotide dication-crown-ether complexes and characterized by UV-vis photodissociation action spectra, ab initio calculations of structures and relative energies, and time-dependent density functional theory calculations of UV-vis absorption spectra. Theoretical calculations indicate that (dGG + 2H)+• cation radicals formed by electron transfer underwent an exothermic conformational collapse that was accompanied by guanine ring stacking and facile internucleobase hydrogen atom transfer, forming 3'-guanine C-8-H radicals. In contrast, exothermic hydrogen transfer from the 5'-cytosine radical onto the guanine ring in (dCG + 2H)+• was kinetically hampered, resulting in the formation of a mixture of 5'-cytosine and 3'-guanine radicals. Conformational folding and nucleobase stacking were energetically unfavorable in (dGC + 2H)+• that retained its structure of a 3'-cytosine radical, as formed by one-electron reduction of the dication. Hydrogen-rich guanine (G + H)• and cytosine (C + H)• radicals were calculated to have vastly different basicities in water, as illustrated by the respective p Ka values of 20.0 and 4.6, which is pertinent to their different abilities to undergo proton-transfer reactions in solution.
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Affiliation(s)
- Yang Liu
- Department of Chemistry, Bagley Hall , University of Washington , P.O. Box 351700, Seattle , Washington 98195-1700 , United States
| | - Joseph A Korn
- Department of Chemistry, Bagley Hall , University of Washington , P.O. Box 351700, Seattle , Washington 98195-1700 , United States
| | - Andy Dang
- Department of Chemistry, Bagley Hall , University of Washington , P.O. Box 351700, Seattle , Washington 98195-1700 , United States
| | - František Tureček
- Department of Chemistry, Bagley Hall , University of Washington , P.O. Box 351700, Seattle , Washington 98195-1700 , United States
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8
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Imaoka N, Houferak C, Murphy MP, Nguyen HTH, Dang A, Tureček F. Spontaneous Isomerization of Peptide Cation Radicals Following Electron Transfer Dissociation Revealed by UV-Vis Photodissociation Action Spectroscopy. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2018; 29:1768-1780. [PMID: 29340957 DOI: 10.1007/s13361-017-1871-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2017] [Revised: 12/06/2017] [Accepted: 12/14/2017] [Indexed: 06/07/2023]
Abstract
Peptide cation radicals of the z-type were produced by electron transfer dissociation (ETD) of peptide dications and studied by UV-Vis photodissociation (UVPD) action spectroscopy. Cation radicals containing the Asp (D), Asn (N), Glu (E), and Gln (Q) residues were found to spontaneously isomerize by hydrogen atom migrations upon ETD. Canonical N-terminal [z4 + H]+● fragment ion-radicals of the R-C●H-CONH- type, initially formed by N-Cα bond cleavage, were found to be minor components of the stable ion fraction. Vibronically broadened UV-Vis absorption spectra were calculated by time-dependent density functional theory for several [●DAAR + H]+ isomers and used to assign structures to the action spectra. The potential energy surface of [●DAAR + H]+ isomers was mapped by ab initio and density functional theory calculations that revealed multiple isomerization pathways by hydrogen atom migrations. The transition-state energies for the isomerizations were found to be lower than the dissociation thresholds, accounting for the isomerization in non-dissociating ions. The facile isomerization in [●XAAR + H]+ ions (X = D, N, E, and Q) was attributed to low-energy intermediates having the radical defect in the side chain that can promote hydrogen migration along backbone Cα positions. A similar side-chain mediated mechanism is suggested for the facile intermolecular hydrogen migration between the c- and [z + H]●-ETD fragments containing Asp, Asn, Glu, and Gln residues. Graphical Abstract ᅟ.
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Affiliation(s)
- Naruaki Imaoka
- Department of Physics, Graduate School of Science, Osaka University, Toyonaka, Osaka, Japan
| | - Camille Houferak
- Department of Chemistry, University of Washington, Box 351700, Seattle, WA, 98195-1700, USA
| | - Megan P Murphy
- Department of Chemistry, University of Washington, Box 351700, Seattle, WA, 98195-1700, USA
| | - Huong T H Nguyen
- Department of Chemistry, University of Washington, Box 351700, Seattle, WA, 98195-1700, USA
| | - Andy Dang
- Department of Chemistry, University of Washington, Box 351700, Seattle, WA, 98195-1700, USA
| | - František Tureček
- Department of Chemistry, University of Washington, Box 351700, Seattle, WA, 98195-1700, USA.
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9
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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: 1.4] [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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10
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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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11
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Dang A, Nguyen HTH, Ruiz H, Piacentino E, Ryzhov V, Tureček F. Experimental Evidence for Noncanonical Thymine Cation Radicals in the Gas Phase. J Phys Chem B 2017; 122:86-97. [DOI: 10.1021/acs.jpcb.7b09872] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Andy Dang
- Department
of Chemistry, University of Washington, Bagley Hall, Box 351700, Seattle, Washington 98195-1700, United States
| | - Huong T. H. Nguyen
- Department
of Chemistry, University of Washington, Bagley Hall, Box 351700, Seattle, Washington 98195-1700, United States
| | - Heather Ruiz
- Department
of Chemistry and Biochemistry, Northern Illinois University, DeKalb, Illinois 60115, United States
| | - Elettra Piacentino
- Department
of Chemistry and Biochemistry, Northern Illinois University, DeKalb, Illinois 60115, United States
| | - Victor Ryzhov
- Department
of Chemistry and Biochemistry, Northern Illinois University, DeKalb, Illinois 60115, United States
| | - František Tureček
- Department
of Chemistry, University of Washington, Bagley Hall, Box 351700, Seattle, Washington 98195-1700, United States
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