Control of the Transition between Ni‐C and Ni‐SIa States by the Redox State of the Proximal FeS Cluster in the Catalytic Cycle of [NiFe] Hydrogenase1. Issue 50 (8th October 2014)

• Record Type: Journal Article
• Authors: Tai, Hulin; Nishikawa, Koji; Suzuki, Masayuki; Higuchi, Yoshiki; Hirota, Shun
• Is Part Of: Angewandte Chemie international edition. Volume 53:Issue 50(2014)
• Page Start: 13817
• Page End: 13820
• Publication Date: 2014-10-08
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201408552
• Languages: English
• ISSNs: 1433-7851

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>[NiFe] hydrogenase catalyzes the reversible cleavage of H₂. The electrons produced by the H₂ cleavage pass through three Fe–S clusters in [NiFe] hydrogenase to its redox partner. It has been reported that the Ni‐SI_a, Ni‐C, and Ni‐R states of [NiFe] hydrogenase are involved in the catalytic cycle, although the mechanism and regulation of the transition between the Ni‐C and Ni‐SI_a states remain unrevealed. In this study, the FT‐IR spectra under light irradiation at 138–198 K show that the Ni‐L state of [NiFe] hydrogenase is an intermediate between the transition of the Ni‐C and Ni‐SI_a states. The transition of the Ni‐C state to the Ni‐SI_a state occurred when the proximal [Fe₄S₄]_p^2+/+ cluster was oxidized, but not when it was reduced. These results show that the catalytic cycle of [NiFe] hydrogenase is controlled by the redox state of its [Fe₄S₄]_p^2+/+ cluster, which may function as a gate for the electron flow from the NiFe active site to the redox partner.</p> </abstract>