Activation process of [NiFe] hydrogenase elucidated by high-resolution X-ray analyses: conversion of the ready to the unready state.
Hydrogenases catalyze oxidoreduction of molecular hydrogen and have potential applications for utilizing dihydrogen as an energy source. [NiFe] hydrogenase has two different oxidized states, Ni-A (unready, exhibits a lag phase in reductive activation) and Ni-B (ready). We have succeeded in converting Ni-B to Ni-A with the use of Na2S and O2 and determining the high-resolution crystal structures of both states. Ni-B possesses a monatomic nonprotein bridging ligand at the Ni-Fe active site, whereas Ni-A has a diatomic species. The terminal atom of the bridging species of Ni-A occupies a similar position as C of the exogenous CO in the CO complex (inhibited state). The common features of the enzyme structures at the unready (Ni-A) and inhibited (CO complex) states are proposed. These findings provide useful information on the design of new systems of biomimetic dihydrogen production and fuel cell devices.
Ogata
Hideaki
H
Department of Life Science, Graduate School of Life Science, University of Hyogo and Himeji Institute of Technology, 3-2-1 Koto, Ako-gun, Hyogo 678-1297, Japan.
Hirota
Shun
S
Nakahara
Asuka
A
Komori
Hirofumi
H
Shibata
Naoki
N
Kato
Tatsuhisa
T
Kano
Kenji
K
Higuchi
Yoshiki
Y
D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D016969:Desulfovibrio vulgaris / Q000201:enzymology; D004578:Electron Spin Resonance Spectroscopy; D004789:Enzyme Activation; D006864:Hydrogenase / Q000737:chemistry* / Q000378:metabolism*; D009532:Nickel / Q000378:metabolism; D017434:Protein Structure, Tertiary; D013440:Sulfides / Q000378:metabolism
D013440:Sulfides; D009532:Nickel; C043296:nickel-iron hydrogenase; D006864:Hydrogenase; C033479:sodium sulfide