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Publication Abstract from PubMed

Maturation of the [FeFe]-hydrogenase active site depends on at least the expression of three gene products called HydE, HydF, and HydG. We have solved the high resolution structure of recombinant, reconstituted S-adenosine-L-methionine-dependent HydE from Thermotoga maritima. Besides the conserved [Fe(4)S(4)] cluster involved in the radical-based reaction, this HydE was reported to have a second [Fe(4)S(4)] cluster coordinated by three Cys residues. However, in our crystals, depending on the reconstitution and soaking conditions, this second cluster is either a [Fe(2)S(2)] center, with water occupying the fourth ligand site or is absent. We have carried out site-directed mutagenesis studies on the related HydE from Clostridium acetobutylicum, along with in silico docking and crystal soaking experiments, to define the active site region and three anion-binding sites inside a large, positive cavity, one of which binds SCN(-) with high affinity. Although the overall triose-phosphate isomerase-barrel structure of HydE is very similar to that of biotin synthase, the residues that line the internal cavity are significantly different in the two enzymes.

X-ray structure of the [FeFe]-hydrogenase maturase HydE from Thermotoga maritima.,Nicolet Y, Rubach JK, Posewitz MC, Amara P, Mathevon C, Atta M, Fontecave M, Fontecilla-Camps JC J Biol Chem. 2008 Jul 4;283(27):18861-72. Epub 2008 Apr 8. PMID:18400755^[2]

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