Article

The role of the maturase HydG in [FeFe]-hydrogenase active site synthesis and assembly.

Laboratoire de Chimie et Biologie des Métaux, Université Joseph Fourier, UMR 5249-CNRS, IRTSV/CEA-Grenoble, Grenoble Cedex, France.
FEBS letters (impact factor: 3.54). 02/2009; 583(3):506-11. DOI:10.1016/j.febslet.2009.01.004 pp.506-11
Source: PubMed

ABSTRACT [FeFe]-hydrogenases catalyze the protons/hydrogen interconversion through a unique di-iron active site consisting of three CO and two CN ligands, and a non-protein SCH(2)XCH(2)S (X=N or O) dithiolate bridge. Site assembly requires two "Radical-S-adenosylmethionine (SAM or AdoMet)" iron-sulfur enzymes, HydE and HydG, and one GTPase, HydF. The sequence homology between HydG and ThiH, a Radical-SAM enzyme which cleaves tyrosine into p-cresol and dehydroglycine, and the finding of a similar cleavage reaction catalyzed by HydG suggests a mechanism for hydrogenase maturation. Here we propose that HydG is specifically involved in the synthesis of the dithiolate ligand, with two tyrosine-derived dehydroglycines as precursors along with an [FeS] cluster of HydG functioning both as electron shuttle and source of the sulfur atoms.

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Keywords

[FeS] cluster
 
dehydroglycine
 
electron shuttle
 
HydF
 
HydG
 
hydrogenase maturation
 
iron-sulfur enzymes
 
non-protein SCH(2)XCH(2)S
 
protons/hydrogen interconversion
 
Radical-SAM enzyme
 
similar cleavage reaction catalyzed
 
Site assembly
 
sulfur atoms
 
tyrosine-derived dehydroglycines
 
unique di-iron active site