title: X-ray-absorption-spectroscopic evidence for a novel iron cluster in hydrogenase II from Clostridium pasteurianum.
abstract: Hydrogenase II from Clostridium pasteurianum contains three different iron-sulphur clusters. Two are [4Fe-4S](2+.1+) clusters, whereas the other, which is thought to be the site of interaction with H2 and is known as the 'H cluster', is of unknown structure and possesses unusual spectroscopic properties. Analysis of the iron e.x.a.f.s. spectra shows that the H cluster contains iron co-ordinated mostly to sulphur and possesses 2.8 A (1 A = 0.1 nm) Fe--Fe separations when oxidized and 3.3 A Fe--Fe separations when reduced with H2. The data suggest that the reduced H cluster represents a new structural type of iron-sulphur cluster.
authors.affiliation: EXXON Research & Engineering Co., Annandale, NJ 08801.
authors.forename: G N
authors.initials: GN
authors.lastname: George
authors.forename: R C
authors.initials: RC
authors.lastname: Prince
authors.forename: K E
authors.initials: KE
authors.lastname: Stokley
authors.forename: M W
authors.initials: MW
authors.lastname: Adams
authors.forename: K E
authors.initials: KE
authors.lastname: Stockley
mesh_terms: D003013:Clostridium / Q000201:enzymology*; D006864:Hydrogenase; D007501:Iron; D013057:Spectrum Analysis; D014965:X-Rays
chemical_list: D007501:Iron; D006864:Hydrogenase