Professor Todd Martinez
Department of Chemistry and The Beckman Institute
University of Illinois at Urbana-Champaign
Urbana, Illinois

Monday, February 21, 2000
3:00 pm (CT)
3269 Beckman Institute

Abstract

Many photoactive proteins employ cis-trans isomerization or ring-opening of a chromophore. The initial photochemical event triggers global shape changes that lead to varied functions such as ion transport and signaling. To varying degrees, it is important that the proteins control the outcome of the photochemical reaction, for example by isomerizing about a specific bond. Understanding the role of the protein environment in modifying the outcome of the photochemical events requires a detailed understanding of both isolated and protein-bound chromophore reactivity. We have attacked the problem on three fronts using ab initio quantum molecular dynamics to study photochemistry of small molecules, ab initio quantum chemistry to elucidate important features in the ground and excited state potential energy surfaces of large models of the relevant chromophores, and quantum molecular dynamics with ab initio-derived potential energy surfaces to study the photodynamics of the entire protein-chromophore system. I will discuss our results on all three fronts for two families of proteins, classified by having either retinal protonated Schiff base (the rhodopsins) or cinnamoic acid derivatives (Green Fluorescent and Photoactive Yellow Proteins) as the active chromophore

Tea and coffee will be served in R3151 Beckman Institute at 2:15pm.