title: UV excited-state photoresponse of biochromophore negative ions.
abstract: Members of the green fluorescent protein (GFP) family may undergo irreversible phototransformation upon irradiation with UV light. This provides clear evidence for the importance of the higher-energy photophysics of the chromophore, which remains essentially unexplored. By using time-resolved action and photoelectron spectroscopy together with high-level electronic structure theory, we directly probe and identify higher electronically excited singlet states of the isolated para- and meta-chromophore anions of GFP. These molecular resonances are found to serve as a doorway for very efficient electron detachment in the gas phase. Inside the protein, this band is found to be resonant with the quasicontinuum of a solvated electron, thus enhancing electron transfer from the GFP to the solvent. This suggests a photophysical pathway for photoconversion of the protein, where GFP resonant photooxidation in solution triggers radical redox reactions inside these proteins.
authors.affiliation: Department of Physics and Astronomy, Aarhus University, 8000 Aarhus C (Denmark); Chemistry Department, M.V. Lomonosov Moscow State University, 119991 Moscow (Russia). bochenkova@phys.au.dk.
authors.forename: Anastasia V
authors.initials: AV
authors.lastname: Bochenkova
authors.forename: Benedikte
authors.initials: B
authors.lastname: Klærke
authors.forename: Dennis B
authors.initials: DB
authors.lastname: Rahbek
authors.forename: Jyoti
authors.initials: J
authors.lastname: Rajput
authors.forename: Yoni
authors.initials: Y
authors.lastname: Toker
authors.forename: Lars H
authors.initials: LH
authors.lastname: Andersen
mesh_terms: D004583:Electrons; D049452:Green Fluorescent Proteins / Q000737:chemistry*; D007477:Ions; D056951:Photoelectron Spectroscopy / Q000379:methods*; D014466:Ultraviolet Rays
chemical_list: D007477:Ions; D049452:Green Fluorescent Proteins
keywords: ab initio calculations; action spectroscopy; electron transfer; green fluorescent protein; photophysics