title: Evidence for selenocysteine coordination to the active site nickel in the [NiFeSe]hydrogenases from Desulfovibrio baculatus.
abstract: Ni and Se x-ray absorption spectroscopic studies of the [NiFeSe]hydrogenases from Desulfovibrio baculatus are described. The Ni site geometry is pseudo-octahedral with a coordinating ligand composition of 3-4 (N,O) at 2.06 A, 1-2 (S,Cl) at 2.17 A, and 1 Se at 2.44 A. The Se coordination environment consists of 1 C at 2.0 A and a heavy scatterer M (M = Ni or Fe) at approximately 2.4 A. These results are interpreted in terms of a selenocysteine residue coordinated to the Ni site. The possible role of the Ni-Se site in the catalytic activation of H2 is discussed.
authors.affiliation: Department of Chemistry, University of Georgia, Athens 30602.
authors.forename: M K
authors.initials: MK
authors.lastname: Eidsness
authors.forename: R A
authors.initials: RA
authors.lastname: Scott
authors.forename: B C
authors.initials: BC
authors.lastname: Prickril
authors.forename: D V
authors.initials: DV
authors.lastname: DerVartanian
authors.forename: J
authors.initials: J
authors.lastname: Legall
authors.forename: I
authors.initials: I
authors.lastname: Moura
authors.forename: J J
authors.initials: JJ
authors.lastname: Moura
authors.forename: H D
authors.initials: HD
authors.lastname: Peck
mesh_terms: D001665:Binding Sites; D003545:Cysteine / Q000031:analogs & derivatives*; D003901:Desulfovibrio / Q000201:enzymology*; D006864:Hydrogenase / Q000378:metabolism*; D007501:Iron / Q000378:metabolism; D008666:Metalloendopeptidases / Q000378:metabolism*; D009532:Nickel; D010084:Oxidation-Reduction; D011487:Protein Conformation; D012643:Selenium / Q000378:metabolism; D017279:Selenocysteine; D013057:Spectrum Analysis
chemical_list: D017279:Selenocysteine; D009532:Nickel; D007501:Iron; D006864:Hydrogenase; D008666:Metalloendopeptidases; D012643:Selenium; D003545:Cysteine