title: Vanadium K-edge X-ray-absorption spectroscopy of the functioning and thionine-oxidized forms of the VFe-protein of the vanadium nitrogenase from Azotobacter chroococcum.
abstract: Vanadium K-edge X-ray-absorption spectra were collected for samples of thionine-oxidized, super-reduced (during enzyme turnover) and dithionite-reduced VFe-protein of the vanadium nitrogenase of Azotobacter chroococcum (Acl*). Both the e.x.a.f.s and the x.a.n.e.s. (X-ray-absorption near-edge structure) are consistent with the vanadium being present as part of a VFeS cluster; the environment of the vanadium is not changed significantly in different oxidation states of the protein. The vanadium atom is bound to three oxygen (or nitrogen), three sulphur and three iron atoms at 0.215(3), 0.231(3) and 0.275(3) nm respectively.
authors.affiliation: Department of Chemistry, University of Manchester, U.K.
authors.forename: J M
authors.initials: JM
authors.lastname: Arber
authors.forename: B R
authors.initials: BR
authors.lastname: Dobson
authors.forename: R R
authors.initials: RR
authors.lastname: Eady
authors.forename: S S
authors.initials: SS
authors.lastname: Hasnain
authors.forename: C D
authors.initials: CD
authors.lastname: Garner
authors.forename: T
authors.initials: T
authors.lastname: Matsushita
authors.forename: M
authors.initials: M
authors.lastname: Nomura
authors.forename: B E
authors.initials: BE
authors.lastname: Smith
mesh_terms: D001395:Azotobacter / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism*; D008667:Metalloproteins / Q000378:metabolism*; D009591:Nitrogenase / Q000378:metabolism*; D010084:Oxidation-Reduction; D010640:Phenothiazines / Q000378:metabolism*; D013057:Spectrum Analysis; D014639:Vanadium; D014965:X-Rays
chemical_list: D001426:Bacterial Proteins; D008667:Metalloproteins; D010640:Phenothiazines; C052750:vanadium-iron protein, Azotobacter; D014639:Vanadium; D009591:Nitrogenase; C009469:thionine