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Control of the Transition between Ni‐C and Ni‐SI a States by the Redox State of the Proximal FeS Cluster in the Catalytic Cycle of [NiFe] Hydrogenase
Author(s) -
Tai Hulin,
Nishikawa Koji,
Suzuki Masayuki,
Higuchi Yoshiki,
Hirota Shun
Publication year - 2014
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201408552
Subject(s) - cluster (spacecraft) , hydrogenase , redox , catalysis , transition metal , state (computer science) , oxidation state , nickel , catalytic cycle , materials science , crystallography , chemistry , inorganic chemistry , metallurgy , mathematics , computer science , biochemistry , programming language , algorithm
Abstract [NiFe] hydrogenase catalyzes the reversible cleavage of H 2 . The electrons produced by the H 2 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 [Fe 4 S 4 ] 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 [Fe 4 S 4 ] p 2+/+ cluster, which may function as a gate for the electron flow from the NiFe active site to the redox partner.