TY  - JOUR
AU  - Ortiz-Mahecha, Carlos
AU  - Schwob, Lucas
AU  - Leroux, Juliette
AU  - Bari, Sadia
AU  - Meissner, Robert
AU  - Bande, Annika
TI  - X-ray absorption spectroscopy reveals charge transfer in π-stacked aromatic amino acids
JO  - Physical chemistry, chemical physics
VL  - 27
IS  - 16
SN  - 1463-9076
CY  - Cambridge
PB  - RSC Publ.
M1  - PUBDB-2025-04829
SP  - 8202 - 8211
PY  - 2025
AB  - 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.
LB  - PUB:(DE-HGF)16
DO  - DOI:10.1039/D4CP04615C
UR  - https://bib-pubdb1.desy.de/record/640689
ER  -