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Leroux J, Kotobi A, Hirsch K, Lau T, Ortiz-Mahecha C, Maksimov D, Meißner R, Oostenrijk B, Rossi M, Schubert K, Timm M, Trinter F, Unger I, Zamudio-Bayer V, Schwob L, Bari S. Mapping the electronic transitions of protonation sites in peptides using soft X-ray action spectroscopy. Phys Chem Chem Phys 2023; 25:25603-25618. [PMID: 37721108 DOI: 10.1039/d3cp02524a] [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: 09/19/2023]
Abstract
Near-edge X-ray absorption mass spectrometry (NEXAMS) around the nitrogen and oxygen K-edges was employed on gas-phase peptides to probe the electronic transitions related to their protonation sites, namely at basic side chains, the N-terminus and the amide oxygen. The experimental results are supported by replica exchange molecular dynamics and density-functional theory and restricted open-shell configuration with single calculations to attribute the transitions responsible for the experimentally observed resonances. We studied five tailor-made glycine-based pentapeptides, where we identified the signature of the protonation site of N-terminal proline, histidine, lysine and arginine, at 406 eV, corresponding to N 1s → σ*(NHx+) (x = 2 or 3) transitions, depending on the peptides. We compared the spectra of pentaglycine and triglycine to evaluate the sensitivity of NEXAMS to protomers. Separate resonances have been identified to distinguish two protomers in triglycine, the protonation site at the N-terminus at 406 eV and the protonation site at the amide oxygen characterized by a transition at 403.1 eV.
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Affiliation(s)
- Juliette Leroux
- CIMAP, CEA/CNRS/ENSICAEN/Université de Caen Normandie, 14050 Caen, France
- Deutsches Elektronen-Synchrotron DESY, Germany.
| | - Amir Kotobi
- Deutsches Elektronen-Synchrotron DESY, Germany.
- Helmholtz-Zentrum Hereon, Institute of Surface Science, 21502 Geesthacht, Germany
| | - Konstantin Hirsch
- Abteilung Hochempfindliche Röntgenspektroskopie, Helmholtz-Zentrum Berlin für Materialien und Energie, 12489 Berlin, Germany
| | - Tobias Lau
- Abteilung Hochempfindliche Röntgenspektroskopie, Helmholtz-Zentrum Berlin für Materialien und Energie, 12489 Berlin, Germany
| | - Carlos Ortiz-Mahecha
- Hamburg University of Technology, Institute of Polymers and Composites, 21073 Hamburg, Germany
| | - Dmitrii Maksimov
- Max Planck Institute for the Structure and Dynamics of Matter, 22761 Hamburg, Germany
| | - Robert Meißner
- Helmholtz-Zentrum Hereon, Institute of Surface Science, 21502 Geesthacht, Germany
- Hamburg University of Technology, Institute of Polymers and Composites, 21073 Hamburg, Germany
| | | | - Mariana Rossi
- Max Planck Institute for the Structure and Dynamics of Matter, 22761 Hamburg, Germany
| | | | - Martin Timm
- Abteilung Hochempfindliche Röntgenspektroskopie, Helmholtz-Zentrum Berlin für Materialien und Energie, 12489 Berlin, Germany
| | - Florian Trinter
- Institut für Kernphysik, Goethe-Universität Frankfurt am Main, 60438 Frankfurt am Main, Germany
- Molecular Physics, Fritz-Haber-Institut der Max-Planck-Gesellschaft, 14195 Berlin, Germany
| | - Isaak Unger
- Department of Physics and Astronomy, Uppsala University, 75120 Uppsala, Sweden
| | - Vicente Zamudio-Bayer
- Abteilung Hochempfindliche Röntgenspektroskopie, Helmholtz-Zentrum Berlin für Materialien und Energie, 12489 Berlin, Germany
| | | | - Sadia Bari
- Deutsches Elektronen-Synchrotron DESY, Germany.
- The Hamburg Centre for Ultrafast Imaging, Hamburg, Germany
- Zernike Institute for Advanced Materials, University of Groningen, 9747 AG Groningen, The Netherlands
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2
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Gopakumar G, Svensson PHW, Grånäs O, Brena B, Schwob L, Unger I, Saak CM, Timm M, Bülow C, Kubin M, Zamudio-Bayer V, Lau JT, von Issendorff B, Abid AR, Lindblad A, Danielsson E, Koerfer E, Caleman C, Björneholm O, Lindblad R. X-ray Induced Fragmentation of Protonated Cystine. J Phys Chem A 2022; 126:1496-1503. [PMID: 35213156 PMCID: PMC8919253 DOI: 10.1021/acs.jpca.1c10158] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We demonstrate site-specific X-ray induced fragmentation across the sulfur L-edge of protonated cystine, the dimer of the amino acid cysteine. Ion yield NEXAFS were performed in the gas phase using electrospray ionization (ESI) in combination with an ion trap. The interpretation of the sulfur L-edge NEXAFS spectrum is supported by Restricted Open-Shell Configuration Interaction (ROCIS) calculations. The fragmentation pathway of triply charged cystine ions was modeled by Molecular Dynamics (MD) simulations. We have deduced a possible pathway of fragmentation upon excitation and ionization of S 2p electrons. The disulfide bridge breaks for resonant excitation at lower photon energies but remains intact upon higher energy resonant excitation and upon ionization of S 2p. The larger fragments initially formed subsequently break into smaller fragments.
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Affiliation(s)
- Geethanjali Gopakumar
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden
| | - Pamela H W Svensson
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden
| | - Oscar Grånäs
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden
| | - Barbara Brena
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden
| | - Lucas Schwob
- Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, DE-22607 Hamburg, Germany
| | - Isaak Unger
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden
| | - Clara-Magdalena Saak
- Department of Physical Chemistry, University of Vienna, Währingerstraßze 42, 1090 Vienna, Austria
| | - Martin Timm
- Abteilung für Hochempfindliche Röntgenspektroskopie, Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, DE-12489 Berlin, Germany.,Institut für Optik und Atomare Physik, Technische Universität Berlin, Hardenbergstrasse 36, DE-10623 Berlin, Germany
| | - Christine Bülow
- Abteilung für Hochempfindliche Röntgenspektroskopie, Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, DE-12489 Berlin, Germany.,Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Strasse 3, DE-79104 Freiburg, Germany
| | - Markus Kubin
- Abteilung für Hochempfindliche Röntgenspektroskopie, Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, DE-12489 Berlin, Germany
| | - Vicente Zamudio-Bayer
- Abteilung für Hochempfindliche Röntgenspektroskopie, Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, DE-12489 Berlin, Germany
| | - J Tobias Lau
- Abteilung für Hochempfindliche Röntgenspektroskopie, Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, DE-12489 Berlin, Germany.,Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Strasse 3, DE-79104 Freiburg, Germany
| | - Bernd von Issendorff
- Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Strasse 3, DE-79104 Freiburg, Germany
| | - Abdul R Abid
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden.,Nano and Molecular Systems Research Unit, Faculty of Science, University of Oulu, P.O. Box 3000, 90570 Oulu, Finland
| | - Andreas Lindblad
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden
| | - Emma Danielsson
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden
| | - Ebba Koerfer
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden
| | - Carl Caleman
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden.,Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, DE-22607 Hamburg, Germany
| | - Olle Björneholm
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden
| | - Rebecka Lindblad
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden.,Abteilung für Hochempfindliche Röntgenspektroskopie, Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, DE-12489 Berlin, Germany.,Department of Physics, Lund University, Box 118, SE-22100 Lund, Sweden.,Department of Chemistry - Ångström Laboratory, Uppsala University, Box 538, SE-75121 Uppsala, Sweden
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3
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Couto RC, Hua W, Lindblad R, Kjellsson L, Sorensen SL, Kubin M, Bülow C, Timm M, Zamudio-Bayer V, von Issendorff B, Söderström J, Lau JT, Rubensson JE, Ågren H, Carravetta V. Breaking inversion symmetry by protonation: experimental and theoretical NEXAFS study of the diazynium ion, N 2H . Phys Chem Chem Phys 2021; 23:17166-17176. [PMID: 34346432 DOI: 10.1039/d1cp02002a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
As an example of symmetry breaking in NEXAFS spectra of protonated species we present a high resolution NEXAFS spectrum of protonated dinitrogen, the diazynium ion N2H+. By ab initio calculations we show that the spectrum consists of a superposition of two nitrogen 1s absorption spectra, each including a π* band, and a nitrogen 1s to H+ charge transfer band followed by a weak irregular progression of high energy excitations. Calculations also show that, as an effect of symmetry breaking by protonation, the π* transitions are separated by 0.23 eV, only slightly exceeding the difference in the corresponding dark (symmetry forbidden) and bright (symmetry allowed) core excitations of neutral N2. By DFT and calculations and vibrational analysis, the complex π* excitation band of N2H+ is understood as due to the superposition of the significantly different vibrational progressions of excitations from terminal and central nitrogen atoms, both leading to bent final state geometries. We also show computationally that the electronic structure of the charge transfer excitation smoothly depends on the nitrogen-proton distance and that there is a clear extension of the spectra going from infinity to close nitrogen-proton distance where fine structures show some, although not fully detailed, similarities. An interesting feature of partial localization of the nitrogen core orbitals, with a strong, non-monotonous, variation with nitrogen-proton distance could be highlighted. Specific effects could be unraveled when comparing molecular cation NEXAFS spectra, as represented by recently recorded spectra of N2+ and CO+, and spectra of protonated molecules as represented here by the N2H+ ion. Both types containing rich physical effects not represented in NEXAFS of neutral molecules because of the positive charge, whereas protonation also breaks the symmetry. The effect of the protonation on dinitrogen can be separated in charge, which extends the high-energy part of the spectrum, and symmetry-breaking, which is most clearly seen in the low-energy π* transition.
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Affiliation(s)
- Rafael C Couto
- Department of Theoretical Chemistry and Biology, School of Chemistry, Biotechnology and Health, Royal Institute of Technology, SE-106 91, Stockholm, Sweden.
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4
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Dörner S, Schwob L, Atak K, Schubert K, Boll R, Schlathölter T, Timm M, Bülow C, Zamudio-Bayer V, von Issendorff B, Lau JT, Techert S, Bari S. Probing Structural Information of Gas-Phase Peptides by Near-Edge X-ray Absorption Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2021; 32:670-684. [PMID: 33573373 DOI: 10.1021/jasms.0c00390] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Near-edge X-ray absorption mass spectrometry (NEXAMS) is an action-spectroscopy technique of growing interest for investigations into the spatial and electronic structure of biomolecules. It has been used successfully to give insights into different aspects of the photodissociation of peptides and to probe the conformation of proteins. It is a current question whether the fragmentation pathways are sensitive toward effects of conformational isomerism, tautomerism, and intramolecular interactions in gas-phase peptides. To address this issue, we studied the cationic fragments of cryogenically cooled gas-phase leucine enkephalin ([LeuEnk+H]+) and methionine enkephalin ([MetEnk+H]+) produced upon soft X-ray photon absorption at the carbon, nitrogen, and oxygen K-edges. The interpretation of the experimental ion yield spectra was supported by density-functional theory and restricted-open-shell configuration interaction with singles (DFT/ROCIS) calculations. The analysis revealed several effects that could not be rationalized based on the peptide's amino acid sequences alone. Clear differences between the partial ion yields measured for both peptides upon C 1s → π*(C═C) excitations in the aromatic amino acid side chains give evidence for a sulfur-aromatic interaction between the methionine and phenylalanine side chain of [MetEnk+H]+. Furthermore, a peak associated with N 1s → π*(C═N) transitions, linked to a tautomeric keto-to-enol conversion of peptide bonds, was only present in the photon energy resolved ion yield spectra of [MetEnk+H]+.
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Affiliation(s)
- Simon Dörner
- Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Lucas Schwob
- Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Kaan Atak
- Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Kaja Schubert
- Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Rebecca Boll
- Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany
- European XFEL, Holzkoppel 4, 22869 Schenefeld, Germany
| | - Thomas Schlathölter
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - Martin Timm
- Abteilung Hochempfindliche Röntgenspektroskopie, Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
| | - Christine Bülow
- Abteilung Hochempfindliche Röntgenspektroskopie, Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
| | - Vicente Zamudio-Bayer
- Abteilung Hochempfindliche Röntgenspektroskopie, Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
| | - Bernd von Issendorff
- Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Strasse 3, 79104 Freiburg, Germany
| | - J Tobias Lau
- Abteilung Hochempfindliche Röntgenspektroskopie, Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
- Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Strasse 3, 79104 Freiburg, Germany
| | - Simone Techert
- Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany
- Institut für Röntgenphysik, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Sadia Bari
- Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany
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5
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Schwob L, Dörner S, Atak K, Schubert K, Timm M, Bülow C, Zamudio-Bayer V, von Issendorff B, Lau JT, Techert S, Bari S. Site-Selective Dissociation upon Sulfur L-Edge X-ray Absorption in a Gas-Phase Protonated Peptide. J Phys Chem Lett 2020; 11:1215-1221. [PMID: 31978303 DOI: 10.1021/acs.jpclett.0c00041] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Site-selective dissociation induced by core photoexcitation of biomolecules is of key importance for the understanding of radiation damage processes and dynamics and for its promising use as "chemical scissors" in various applications. However, identifying products of site-selective dissociation in large molecules is challenging at the carbon, nitrogen, and oxygen edges because of the high recurrence of these atoms and related chemical groups. In this paper, we present the observation of site-selective dissociation at the sulfur L-edge in the gas-phase peptide methionine enkephalin, which contains only a single sulfur atom. Near-edge X-ray absorption mass spectrometry has revealed that the resonant S 2p → σ*C-S excitation of the sulfur contained in the methionine side chain leads to site-selective dissociation, which is not the case after core ionization above the sulfur L-edge. The prospects of such results for the study of charge dynamics in biomolecular systems are discussed.
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Affiliation(s)
- Lucas Schwob
- Deutsches Elektronen-Synchrotron DESY , Notkestrasse 85 , 22607 Hamburg , Germany
| | - Simon Dörner
- Deutsches Elektronen-Synchrotron DESY , Notkestrasse 85 , 22607 Hamburg , Germany
| | - Kaan Atak
- Deutsches Elektronen-Synchrotron DESY , Notkestrasse 85 , 22607 Hamburg , Germany
| | - Kaja Schubert
- Deutsches Elektronen-Synchrotron DESY , Notkestrasse 85 , 22607 Hamburg , Germany
| | - Martin Timm
- Abteilung für Hochempfindliche Röntgenspektroskopie , Helmholtz Zentrum Berlin für Materialien und Energie , Albert-Einstein-Strasse 15 , 12489 Berlin , Germany
| | - Christine Bülow
- Abteilung für Hochempfindliche Röntgenspektroskopie , Helmholtz Zentrum Berlin für Materialien und Energie , Albert-Einstein-Strasse 15 , 12489 Berlin , Germany
| | - Vicente Zamudio-Bayer
- Abteilung für Hochempfindliche Röntgenspektroskopie , Helmholtz Zentrum Berlin für Materialien und Energie , Albert-Einstein-Strasse 15 , 12489 Berlin , Germany
| | - Bernd von Issendorff
- Physikalisches Institut , Universität Freiburg , Hermann-Herder-Straße 3 , 79104 Freiburg , Germany
| | - J Tobias Lau
- Abteilung für Hochempfindliche Röntgenspektroskopie , Helmholtz Zentrum Berlin für Materialien und Energie , Albert-Einstein-Strasse 15 , 12489 Berlin , Germany
- Physikalisches Institut , Universität Freiburg , Hermann-Herder-Straße 3 , 79104 Freiburg , Germany
| | - Simone Techert
- Deutsches Elektronen-Synchrotron DESY , Notkestrasse 85 , 22607 Hamburg , Germany
- Institute of X-ray Physics , University of Göttingen , Friedrich-Hund-Platz 1 , 37077 Göttingen , Germany
| | - Sadia Bari
- Deutsches Elektronen-Synchrotron DESY , Notkestrasse 85 , 22607 Hamburg , Germany
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