1. Structural and spectroscopic characterization of CO inhibition of [NiFe]‐hydrogenase from Citrobacter sp. S‐77.
- Author
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Imanishi, Takahiro, Nishikawa, Koji, Taketa, Midori, Higuchi, Katsuhiro, Tai, Hulin, Hirota, Shun, Hojo, Hironobu, Kawakami, Toru, Hataguchi, Kiriko, Matsumoto, Kayoko, Ogata, Hideaki, and Higuchi, Yoshiki
- Subjects
X-ray crystallography technique ,CITROBACTER ,ELECTRON paramagnetic resonance spectroscopy ,CARBON monoxide ,INFRARED spectroscopy ,CRYSTAL structure - Abstract
Hydrogenases catalyze the reversible oxidation of H2. Carbon monoxide (CO) is known to be a competitive inhibitor of O2‐sensitive [NiFe]‐hydrogenases. Although the activities of some O2‐tolerant [NiFe]‐hydrogenases are unaffected by CO, the partially O2‐tolerant [NiFe]‐hydrogenase from Citrobacter sp. S‐77 (S77‐HYB) is inhibited by CO. In this work, the CO‐bound state of S77‐HYB was characterized by activity assays, spectroscopic techniques and X‐ray crystallography. Electron paramagnetic resonance spectroscopy showed a diamagnetic Ni2+ state, and Fourier‐transform infrared spectroscopy revealed the stretching vibration of the exogenous CO ligand. The crystal structure determined at 1.77 Å resolution revealed that CO binds weakly to the nickel ion in the Ni–Fe active site of S77‐HYB. These results suggest a positive correlation between O2 and CO tolerance in [NiFe]‐hydrogenases. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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