title: Semiempirical configuration interaction calculations in biochemical environments: parametrization and application to γD-crystallin, an eye-lens protein.
abstract: We approach the problem of optical excitations in molecular aggregates in complex biochemical environments from a computational, all-atom perspective. The system is divided into a π orbital part described by a Pariser-Parr-Pople model with configuration interaction using singly excited Slater determinants (PPP-CIS). It is coupled to the protein and water charges of a classical force field. Strategies for a high-accuracy reparameterization and an efficient computational solution are presented. For γD-crystallin, a band edge consisting of charge-transfer states emerges for a coupled molecular aggregate compared to the uncoupled residues. The energies of some charge-transfer states strongly depend on the dielectric properties of the model, giving a first insight into the potential temporal evolution of these excitations. Possible biochemical implications are discussed.
authors.affiliation: Institut für Physikalische Chemie, Universität Freiburg, Albertstraße 23a, D-79104 Freiburg im Breisgau, Germany.
authors.forename: Sandra
authors.initials: S
authors.lastname: Kruse
authors.forename: Sebastian
authors.initials: S
authors.lastname: Krapf
authors.forename: Benjamin
authors.initials: B
authors.lastname: Lampe
authors.forename: Thorsten
authors.initials: T
authors.lastname: Koslowski
mesh_terms: D003459:Crystallins / Q000737:chemistry*; D006801:Humans; D008958:Models, Molecular; D008968:Molecular Conformation; D038222:gamma-Crystallins / Q000737:chemistry*
chemical_list: D003459:Crystallins; D038222:gamma-Crystallins