Erratum in:

Science 1999 Jan 1;283(5398):35.

Science 1999 Mar 26;283(5410):2102.

Comment in:

Science. 1998 Dec 4;282(5395):1842-3.

X-ray crystal structure of the Fe-only hydrogenase (CpI) from Clostridium pasteurianum to 1.8 angstrom resolution.

Department of Chemistry and Biochemistry, Utah State University, Logan, UT 84322, USA. petersj@cc.usu.edu

A three-dimensional structure for the monomeric iron-containing hydrogenase (CpI) from Clostridium pasteurianum was determined to 1.8 angstrom resolution by x-ray crystallography using multiwavelength anomalous dispersion (MAD) phasing. CpI, an enzyme that catalyzes the two-electron reduction of two protons to yield dihydrogen, was found to contain 20 gram atoms of iron per mole of protein, arranged into five distinct [Fe-S] clusters. The probable active-site cluster, previously termed the H-cluster, was found to be an unexpected arrangement of six iron atoms existing as a [4Fe-4S] cubane subcluster covalently bridged by a cysteinate thiol to a [2Fe] subcluster. The iron atoms of the [2Fe] subcluster both exist with an octahedral coordination geometry and are bridged to each other by three non-protein atoms, assigned as two sulfide atoms and one carbonyl or cyanide molecule. This structure provides insights into the mechanism of biological hydrogen activation and has broader implications for [Fe-S] cluster structure and function in biological systems.

PMID: 9836629 [PubMed - indexed for MEDLINE]