title: Analogue chromophore study of the influence of electronic perturbation on color regulation of photoactive yellow protein.
abstract: We report a unique lambdamax shift of the absorption maximum of a photoactive yellow protein (PYP) analogue reconstituted with a fluorinated chromophore (F-PYP). The difference in lambdamax between the free chromophore and the protein was significantly larger than that with the native chromophore. We concluded that the unusual lambdamax shift is caused by the electronegative character of the fluorine atom and not by steric hindrance. This result suggests that formation of a hydrogen bond between the fluorine atom and one or more amino acid residues could neutralize its electron-withdrawing character. The properties of analogues of PYP with brominated and methylated chromophore could be explained as an effect of steric hindrance.
authors.affiliation: Department of Earth and Space Science, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yamada
authors.forename: Masato
authors.initials: M
authors.lastname: Kumauchi
authors.forename: Norio
authors.initials: N
authors.lastname: Hamada
authors.forename: Xiang-Guo
authors.initials: XG
authors.lastname: Zheng
authors.forename: Il Ho
authors.initials: IH
authors.lastname: Park
authors.forename: Katsuyoshi
authors.initials: K
authors.lastname: Masuda
authors.forename: Kazuo
authors.initials: K
authors.lastname: Yoshihara
authors.forename: Fumio
authors.initials: F
authors.lastname: Tokunaga
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry*; D003116:Color; D004563:Electrochemistry; D006863:Hydrogen-Ion Concentration; D020283:Photoreceptors, Microbial / Q000737:chemistry*; D013053:Spectrophotometry; D013056:Spectrophotometry, Ultraviolet
chemical_list: D001426:Bacterial Proteins; D020283:Photoreceptors, Microbial; C050162:photoactive yellow protein, Bacteria