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Publication Abstract from PubMed

Hydrogenases catalyze the reversible oxidation of H(2). Carbon monoxide (CO) is known to be a competitive inhibitor of O(2)-sensitive [NiFe]-hydrogenases. Although the activities of some O(2)-tolerant [NiFe]-hydrogenases are unaffected by CO, the partially O(2)-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 Ni(2+) state, and Fourier-transform infrared spectroscopy revealed the stretching vibration of the exogenous CO ligand. The crystal structure determined at 1.77 A 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 O(2) and CO tolerance in [NiFe]-hydrogenases.

Structural and spectroscopic characterization of CO inhibition of [NiFe]-hydrogenase from Citrobacter sp. S-77.,Imanishi T, Nishikawa K, Taketa M, Higuchi K, Tai H, Hirota S, Hojo H, Kawakami T, Hataguchi K, Matsumoto K, Ogata H, Higuchi Y Acta Crystallogr F Struct Biol Commun. 2022 Feb 1;78(Pt 2):66-74. doi: , 10.1107/S2053230X22000188. Epub 2022 Jan 27. PMID:35102895^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.