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Mapping the electronic transitions of protonation sites in peptides using soft X-ray action spectroscopy
Citation Link: https://doi.org/10.15480/882.8767
Publikationstyp
Journal Article
Publikationsdatum
2023-09-18
Sprache
English
Author
Leroux, Juliette
Lau, Tobias
Timm, Martin
Unger, Isaak
Zamudio-Bayer, Vicente
Enthalten in
Volume
25
Issue
37
Start Page
25603
End Page
25618
Citation
Physical Chemistry Chemical Physics 25 (37): 25603-25618 (2023-09-18)
Publisher DOI
Scopus ID
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.
DDC Class
530: Physics
540: Chemistry
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publishedVersion
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