Evidence for selenocysteine coordination to the active site nickel in the [NiFeSe]hydrogenases from Desulfovibrio baculatus

Proc Natl Acad Sci U S A. 1989 Jan;86(1):147-51. doi: 10.1073/pnas.86.1.147.

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.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Binding Sites
  • Cysteine / analogs & derivatives*
  • Desulfovibrio / enzymology*
  • Hydrogenase / metabolism*
  • Iron / metabolism
  • Metalloendopeptidases / metabolism*
  • Nickel*
  • Oxidation-Reduction
  • Protein Conformation
  • Selenium* / metabolism
  • Selenocysteine
  • Spectrum Analysis

Substances

  • Selenocysteine
  • Nickel
  • Iron
  • Hydrogenase
  • Metalloendopeptidases
  • Selenium
  • Cysteine