title: Photosensitivity of the Ni-A state of [NiFe] hydrogenase from Desulfovibrio vulgaris Miyazaki F with visible light.
abstract: [NiFe] hydrogenase catalyzes reversible oxidation of molecular hydrogen. Its active site is constructed of a hetero dinuclear Ni-Fe complex, and the oxidation state of the Ni ion changes according to the redox state of the enzyme. We found that the Ni-A state (an inactive unready, oxidized state) of [NiFe] hydrogenase from Desulfovibrio vulgaris Miyazaki F (DvMF) is light sensitive and forms a new state (Ni-AL) with irradiation of visible light. The Fourier transform infrared (FT-IR) bands at 1956, 2084 and 2094 cm(-1) of the Ni-A state shifted to 1971, 2086 and 2098 cm(-1) in the Ni-AL state. The g-values of g(x)=2.30, g(y)=2.23 and g(z)=2.01 for the signals in the electron paramagnetic resonance (EPR) spectrum of the Ni-A state at room temperature varied for -0.009, +0.012 and +0.010, respectively, upon light irradiation. The light-induced Ni-AL state converted back immediately to the Ni-A state under dark condition at room temperature. These results show that the coordination structure of the Fe site of the Ni-A state of [NiFe] hydrogenase is perturbed significantly by light irradiation with relatively small coordination change at the Ni site.
authors.affiliation: Graduate School of Life Science, University of Hyogo, 3-2-1, Koto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan.
authors.forename: Hisao
authors.initials: H
authors.lastname: Osuka
authors.forename: Yasuhito
authors.initials: Y
authors.lastname: Shomura
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Komori
authors.forename: Naoki
authors.initials: N
authors.lastname: Shibata
authors.forename: Satoshi
authors.initials: S
authors.lastname: Nagao
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Higuchi
authors.forename: Shun
authors.initials: S
authors.lastname: Hirota
mesh_terms: D016969:Desulfovibrio vulgaris / Q000201:enzymology*; D006864:Hydrogenase / Q000737:chemistry / Q000528:radiation effects*; D007501:Iron / Q000737:chemistry; D008027:Light; D009532:Nickel / Q000737:chemistry; D055668:Photochemical Processes; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D009532:Nickel; D007501:Iron; C043296:nickel-iron hydrogenase; D006864:Hydrogenase