title: The CO and CN(-) ligands to the active site Fe in [NiFe]-hydrogenase of Escherichia coli have different metabolic origins.
abstract: The Fe atom in the bimetallic active site of [NiFe]-hydrogenases has one CO and two cyanide ligands. To determine their metabolic origin, [NiFe]-hydrogenase-2 was isolated from Escherichia coli grown in the presence of L-[ureido-(13)C]citrulline, purified and analyzed by infrared spectroscopy. The spectra indicate incorporation of (13)C only into the cyanide ligands and not into the CO, showing that cyanide and CO have different metabolic origins. After growth of E. coli in the presence of (13)CO only the CO ligand was labelled with (13)C. Labelling did not result from an exchange of the intrinsic CO ligand with the exogenous CO.
authors.affiliation: Max-Planck-Institut für Terrestrische Mikrobiologie, Karl-von-Frisch-Str, Marburg, Germany.
authors.forename: Lucia
authors.initials: L
authors.lastname: Forzi
authors.forename: Petra
authors.initials: P
authors.lastname: Hellwig
authors.forename: Rudolf K
authors.initials: RK
authors.lastname: Thauer
authors.forename: R Gary
authors.initials: RG
authors.lastname: Sawers
mesh_terms: D001665:Binding Sites; D002247:Carbon Isotopes / Q000493:pharmacokinetics; D002248:Carbon Monoxide / Q000378:metabolism*; D002956:Citrulline / Q000493:pharmacokinetics; D003486:Cyanides / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology* / Q000378:metabolism; D006864:Hydrogenase / Q000737:chemistry* / Q000378:metabolism*; D007501:Iron / Q000378:metabolism*; D008024:Ligands; D053858:Metabolic Networks and Pathways / Q000502:physiology
chemical_list: D002247:Carbon Isotopes; D003486:Cyanides; D008024:Ligands; D002956:Citrulline; D002248:Carbon Monoxide; D007501:Iron; C043296:nickel-iron hydrogenase; D006864:Hydrogenase