Electronic spectrum of tryptophan-phenylalanine. A correlated ab initio and time-dependent density functional theory study.
The theoretical electronic spectrum of the tryptophan-phenylalanine bichromophoric dipeptide was obtained for one of the lowest-energy conformer by various high-level computational methods such as complete active space with second order perturbation theory, second-order approximate coupled-cluster theory, and time-dependent density functional theory. The results show that the first excited state is located on the tryptophan residue and called L(b) state in the amino-acid. The second and third excited states correspond respectively to the L(a) state of Trp and the excited state in the Phe residue. Time-dependent density functional methods appeared to be not efficient to calculate the excited states of such a peptide (except the first one) due to the inclusion of charge transfer states.
Clavaguéra
Carine
C
Laboratoire des Mécanismes Réactionnels, Département de Chimie, Ecole Polytechnique, CNRS, 91128 Palaiseau Cedex, France. carine.clavaguera@dcmr.polytechnique.fr
Piuzzi
François
F
Dognon
Jean-Pierre
JP
D004151:Dipeptides / Q000737:chemistry; D004583:Electrons; D010649:Phenylalanine / Q000737:chemistry*; D013997:Time Factors; D014364:Tryptophan / Q000737:chemistry*
D004151:Dipeptides; D010649:Phenylalanine; D014364:Tryptophan