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Biochemical characterization of the HydE and HydG iron‐only hydrogenase maturation enzymes from Thermatoga maritima
Author(s) -
Rubach Jon K.,
Brazzolotto Xavier,
Gaillard Jacques,
Fontecave Marc
Publication year - 2005
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2005.07.092
Subject(s) - carbon monoxide dehydrogenase , thermotoga maritima , hydrogenase , enzyme , chemistry , biochemistry , cyanide , thermophile , dithionite , sulfide , stereochemistry , electron paramagnetic resonance , active site , iron–sulfur cluster , carbon monoxide , escherichia coli , catalysis , organic chemistry , gene , physics , nuclear magnetic resonance
Fe‐only hydrogenases contain a di‐iron active site complex, in which the two Fe atoms have carbon monoxide and cyanide ligands and are linked together by a putative di(thiomethyl)amine molecule. We have cloned, purified and characterized the HydE and HydG proteins, thought to be involved in the biosynthesis of this peculiar metal site, from the thermophilic organism Thermotoga maritima . The HydE protein anaerobically reconstituted with iron and sulfide binds two [4Fe–4S] clusters, as characterized by UV and EPR spectroscopy. The HydG protein binds one [4Fe–4S] cluster, and probably an additional one. Both enzymes are able to reductively cleave S ‐adenosylmethionine (SAM) when reduced by dithionite, confirming that they are Radical‐SAM enzymes.