title: The structure of the Ni-Fe site in the isolated HoxC subunit of the hydrogen-sensing hydrogenase from Ralstonia eutropha.
abstract: The regulatory Ni-Fe hydrogenase (RH) from Ralstonia eutropha which forms a [HoxBC]2 complex functions as a hydrogen sensor under aerobic conditions. We have studied a novel Strep-tag isolate of the RH large subunit, HoxC(ST), which lacks the Fe-S clusters of HoxB, allowing for structure determination of the catalytic site by X-ray absorption spectroscopy both at the Ni and, for the first time, also at the Fe K-edge. This technique, together with Fourier-transform infrared spectroscopy, revealed a Ni-Fe site with [O1(CysS)2Ni(II)(mu-SCys)2Fe(II)(CN)2(CO)] structure in about 50% of HoxC(ST) and a [(CysS)2Fe(II)(CN)2(CO)] site lacking Ni in the remainder protein. Possibly both sites may be intermediates in the maturation process of the RH.
authors.affiliation: Freie Universität Berlin, FB Physik, Arnimallee 14, D-14195 Berlin, Germany.
authors.forename: Simone
authors.initials: S
authors.lastname: Löscher
authors.forename: Ingo
authors.initials: I
authors.lastname: Zebger
authors.forename: Lars K
authors.initials: LK
authors.lastname: Andersen
authors.forename: Peter
authors.initials: P
authors.lastname: Hildebrandt
authors.forename: Wolfram
authors.initials: W
authors.lastname: Meyer-Klaucke
authors.forename: Michael
authors.initials: M
authors.lastname: Haumann
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry*; D020134:Catalytic Domain; D020118:Cupriavidus necator / Q000201:enzymology*; D006859:Hydrogen / Q000378:metabolism; D006864:Hydrogenase / Q000737:chemistry*; D021122:Protein Subunits / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D014965:X-Rays
chemical_list: D001426:Bacterial Proteins; D021122:Protein Subunits; D006859:Hydrogen; C043296:nickel-iron hydrogenase; D006864:Hydrogenase