1. CO and CN- syntheses by [FeFe]-hydrogenase maturase HydG are catalytically differentiated events.
- Author
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Pagnier A, Martin L, Zeppieri L, Nicolet Y, and Fontecilla-Camps JC
- Subjects
- Catalysis, Catalytic Domain, Cysteine chemistry, Desulfovibrio desulfuricans enzymology, Homocysteine chemistry, Hydrogenase genetics, Iron-Sulfur Proteins genetics, Ligands, Protein Structure, Secondary, S-Adenosylmethionine chemistry, Tyrosine chemistry, Carbon Monoxide chemical synthesis, Cyanides chemical synthesis, Hydrogenase chemistry, Iron-Sulfur Proteins chemistry
- Abstract
The synthesis and assembly of the active site [FeFe] unit of [FeFe]-hydrogenases require at least three maturases. The radical S-adenosyl-l-methionine HydG, the best characterized of these proteins, is responsible for the synthesis of the hydrogenase CO and CN(-) ligands from tyrosine-derived dehydroglycine (DHG). We speculated that CN(-) and the CO precursor (-):CO2H may be generated through an elimination reaction. We tested this hypothesis with both wild type and HydG variants defective in second iron-sulfur cluster coordination by measuring the in vitro production of CO, CN(-), and (-):CO2H-derived formate. We indeed observed formate production under these conditions. We conclude that HydG is a multifunctional enzyme that produces DHG, CN(-), and CO at three well-differentiated catalytic sites. We also speculate that homocysteine, cysteine, or a related ligand could be involved in Fe(CO)x(CN)y transfer to the HydF carrier/scaffold.
- Published
- 2016
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