title: Absorption spectrum of the green fluorescent protein chromophore anion in vacuo.
abstract: A sensitive photoabsorption technique for studies of gas-phase biomolecules has been used at the ELISA electrostatic heavy-ion storage ring. We show that the anion form of the chromophore of the green fluorescent protein in vacuo has an absorption maximum at 479 nm, which coincides with one of the two absorption peaks of the protein. Its absorption characteristics are therefore ascribed to intrinsic chemical properties of the chromophore. Evidently, the special beta-can structure of the protein provides shielding of the chromophore from the surroundings without significantly changing the electronic structure of the chromophore through interactions with amino acid side chains.
authors.affiliation: Institute of Physics and Astronomy, Ny Munkegade, Building 520, University of Aarhus, DK-8000 Aarhus C, Denmark.
authors.forename: S B
authors.initials: SB
authors.lastname: Nielsen
authors.forename: A
authors.initials: A
authors.lastname: Lapierre
authors.forename: J U
authors.initials: JU
authors.lastname: Andersen
authors.forename: U V
authors.initials: UV
authors.lastname: Pedersen
authors.forename: S
authors.initials: S
authors.lastname: Tomita
authors.forename: L H
authors.initials: LH
authors.lastname: Andersen
mesh_terms: D000838:Anions; D004797:Enzyme-Linked Immunosorbent Assay; D005740:Gases; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D055672:Static Electricity; D014618:Vacuum
chemical_list: D000838:Anions; D005740:Gases; D008164:Luminescent Proteins; D049452:Green Fluorescent Proteins