title: Color regulation and stabilization of chromophore by Cys69 in photoactive yellow protein active center.
abstract: Model compounds of PYP chromophore were synthesized and characterized to investigate the role of the Cys69 residue in the active center, which has the intramolecular NHOC hydrogen bond to the conjugated carbonyl oxygen and thioester linkage of the chromophore. The results of UV-vis and (13)C NMR spectroscopy of the model compounds indicated that they delocalized the negative charge of the chromophore and increased the contribution of the quinoid-like resonance structure in the phenolate anion state. Thus, the Cys69 residue plays an important role in the regulation of the color and the stabilization of the chromophore anion in the active center.
authors.affiliation: Department of Macromolecular Science, Graduate School of Science, Osaka University, Machikaneyama-cho 1-1, Toyonaka, Osaka 560-0043, Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Okamoto
authors.forename: Norio
authors.initials: N
authors.lastname: Hamada
authors.forename: Taka-aki
authors.initials: TA
authors.lastname: Okamura
authors.forename: Norikazu
authors.initials: N
authors.lastname: Ueyama
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Yamamoto
mesh_terms: D000042:Absorption; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D003116:Color; D003545:Cysteine; D004952:Esters / Q000737:chemistry; D020607:Halorhodospira halophila; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation; D020283:Photoreceptors, Microbial / Q000737:chemistry* / Q000378:metabolism; D055550:Protein Stability; D013056:Spectrophotometry, Ultraviolet; D013455:Sulfur / Q000737:chemistry
chemical_list: D001426:Bacterial Proteins; D004952:Esters; D020283:Photoreceptors, Microbial; C050162:photoactive yellow protein, Bacteria; D013455:Sulfur; D003545:Cysteine