3c8y

Publication Abstract from PubMed

An X-ray crystallographic refinement of the H-cluster of [FeFe]-hydrogenase from Clostridium pasteurianum has been carried out to close-to atomic resolution and is the highest resolution [FeFe]-hydrogenase presented to date. The 1.39 A, anisotropically refined [FeFe]-hydrogenase structure provides a basis for examining the outstanding issue of the composition of the unique nonprotein dithiolate ligand of the H-cluster. In addition to influencing the electronic structure of the H-cluster, the composition of the ligand has mechanistic implications due to the potential of the bridge-head gamma-group participating in proton transfer during catalysis. In this work, sequential density functional theory optimizations of the dithiolate ligand embedded in a 3.5-3.9 A protein environment provide an unbiased approach to examining the most likely composition of the ligand. Structural, conformational, and energetic considerations indicate a preference for dithiomethylether as an H-cluster ligand and strongly disfavor the dithiomethylammonium as a catalytic base for hydrogen production.

Dithiomethylether as a ligand in the hydrogenase h-cluster.,Pandey AS, Harris TV, Giles LJ, Peters JW, Szilagyi RK J Am Chem Soc. 2008 Apr 2;130(13):4533-40. Epub 2008 Mar 7. PMID:18324814^[1]

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