Journal Article

PUBDB-2025-00794

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Tautomerism of a backbone protonated peptide revealed by soft X-ray action spectroscopy

Leroux, J.CFEL*Extern* ; Ortiz Mahecha, C. A.Extern* ; Schubert, K.XFEL.EU*DESY* ; Trinter, F.Extern*XFEL.EU* ; Unger, I.Extern*XFEL.EU* ; Schwob, L.XFEL.EU*DESY* ; Bari, S. (Corresponding author)DESY*

2025
RSC Publ. Cambridge

This record in other databases:      

Please use a persistent id in citations: doi:10.1039/d5cp00506j  doi:10.3204/PUBDB-2025-00794

Abstract: The structure and reactivity of peptides can be influenced by their protonation state. Notably, protonation of the backbone can induce structural changes, such as tautomerism, shifting from the stable keto form to the enol form. This phenomenon, particularly in the backbone protonated peptide acetyl-pentaglycine, was examined using a combination of soft X-ray action spectroscopy at the nitrogen K-edge and theoretical calculations based on density functional theory (DFT). We identified a resonance at 400 eV that can be clearly attributed to $π^*$(C[double bond, length as m-dash]N) transitions, linked exclusively to the enol form, as no keto form structures could replicate this resonance. These findings enhanced our understanding of the effect of protonation on the structure of peptides and could be employed for future dynamic studies.

---

Contributing Institute(s):

1. Biomoleküle in Gasphase (FS-BIG)
2. PETRA-S (FS-PETRA-S)
3. X-ray Atto-Chirality (CFEL-XAC)

Research Program(s):

1. 633 - Life Sciences – Building Blocks of Life: Structure and Function (POF4-633) (POF4-633)
2. 6G3 - PETRA III (DESY) (POF4-6G3) (POF4-6G3)
3. AIM, DFG project G:(GEPRIS)390715994 - EXC 2056: CUI: Advanced Imaging of Matter (390715994) (390715994)
4. FS-Proposal: I-20191057 (I-20191057) (I-20191057)
5. DFG project G:(GEPRIS)509471550 - Dynamik photoionisations-induzierter Prozesse in laser-präparierten Molekülen in der Gasphase und der wässrigen Phase (509471550) (509471550)
6. HIDSS-0002 - DASHH: Data Science in Hamburg - Helmholtz Graduate School for the Structure of Matter (2019_IVF-HIDSS-0002) (2019_IVF-HIDSS-0002)

Experiment(s):

1. PETRA Beamline P04 (PETRA III)

Appears in the scientific report 2025

---

Database coverage:
; ; ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; Essential Science Indicators ; IF < 5 ; JCR ; National-Konsortium ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

---