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Proc Natl Acad Sci U S A. 2016 Jan 5;113(1):104-9. doi: 10.1073/pnas.1515842113. Epub 2015 Dec 22.

CO and CN- syntheses by [FeFe]-hydrogenase maturase HydG are catalytically differentiated events.

Author information

1
Metalloproteins Unit, Institut de Biologie Structurale Commissariat à l'Energie Atomique et aux Energies Renouvelables-Centre National de la Recherche Scientifique-Université Grenoble Alpes, 38044 Grenoble Cedex 9, France.
2
Metalloproteins Unit, Institut de Biologie Structurale Commissariat à l'Energie Atomique et aux Energies Renouvelables-Centre National de la Recherche Scientifique-Université Grenoble Alpes, 38044 Grenoble Cedex 9, France yvain.nicolet@ibs.fr juan.fontecilla@ibs.fr.

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.

KEYWORDS:

CO/CN synthesis; FeFe hydrogenase; HydG maturase; formate; radical SAM enzyme

PMID:
26699472
PMCID:
PMC4711877
DOI:
10.1073/pnas.1515842113
[Indexed for MEDLINE]
Free PMC Article

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