X-ray absorption spectroscopy reveals charge transfer in π-stacked aromatic amino acids
Citation Link: https://doi.org/10.15480/882.15099
Publikationstyp
Journal Article
Date Issued
2025-03-21
Sprache
English
TORE-DOI
Volume
27
Issue
16
Start Page
8202
End Page
821121
Citation
Physical Chemistry Chemical Physics 27 (16): 8202-8211 (2025)
Publisher DOI
Scopus ID
Publisher
Royal Society of Chemistry (RSC)
X-ray absorption spectroscopy (XAS) and quantum mechanical calculations bear great potential to unravel π stacking side-chain interaction properties and structure in, e.g., proteins. However, core-excited state calculations for proteins and their associated interpretation for π-π interactions are challenging due to the complexity of the non-covalent interactions involved. A theoretical analysis is developed to decompose the core-to-valence transitions into their atomic contributions in order to characterize the π stacking of aromatic amino acids as a function of their non-covalent distance change. Three models were studied as a non-covalent mixed dimers of the phenylalanine, tyrosine and tryptophan amino acids. We found that there are carbon 1s → π* charge transfer transitions associated with the non-covalently paired aromatic amino acids through their side chains. The atomic-centered contributions to the electronic transition density quantify the excited state charge transfer of the pairing amino acid models, highlighting the π stacking interactions between their aromatic side chains.
DDC Class
539: Matter; Molecular Physics; Atomic and Nuclear physics; Radiation; Quantum Physics
572: Biochemistry
541: Physical; Theoretical
Publication version
publishedVersion