title: Carbon monoxide as an intrinsic ligand to iron in the active site of the iron-sulfur-cluster-free hydrogenase H2-forming methylenetetrahydromethanopterin dehydrogenase as revealed by infrared spectroscopy.
abstract: The iron-sulfur-cluster-free hydrogenase Hmd (H(2)-forming methylenetetrahydromethanopterin dehydrogenase) from methanogenic archaea has recently been found to contain one iron associated tightly with an extractable cofactor of yet unknown structure. We report here that Hmd contains intrinsic CO bound to the Fe. Chemical analysis of Hmd revealed the presence of 2.4 +/- 0.2 mol of CO/mol of iron. Fourier transform infrared spectra of the native enzyme showed two bands of almost equal intensity at 2011 and 1944 cm(-)(1), interpreted as the stretching frequencies of two CO molecules bound to the same iron in an angle of 90 degrees . We also report on the effect of extrinsic (12)CO, (13)CO, (12)CN(-), and (13)CN(-) on the IR spectrum of Hmd.
authors.affiliation: Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Strasse, D-35043 Marburg, Germany.
authors.forename: Erica J
authors.initials: EJ
authors.lastname: Lyon
authors.forename: Seigo
authors.initials: S
authors.lastname: Shima
authors.forename: Reinhard
authors.initials: R
authors.lastname: Boecher
authors.forename: Rudolf K
authors.initials: RK
authors.lastname: Thauer
authors.forename: Friedrich-Wilhelm
authors.initials: FW
authors.lastname: Grevels
authors.forename: Eckhard
authors.initials: E
authors.lastname: Bill
authors.forename: Winfried
authors.initials: W
authors.lastname: Roseboom
authors.forename: Simon P J
authors.initials: SP
authors.lastname: Albracht
mesh_terms: D019843:Archaeal Proteins / Q000737:chemistry / Q000378:metabolism; D001665:Binding Sites; D001667:Binding, Competitive; D002247:Carbon Isotopes; D002248:Carbon Monoxide / Q000737:chemistry* / Q000378:metabolism; D003486:Cyanides / Q000737:chemistry / Q000378:metabolism; D006859:Hydrogen / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D058085:Iron Compounds / Q000737:chemistry* / Q000378:metabolism; D008027:Light; D017013:Methanobacteriaceae / Q000201:enzymology; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000737:chemistry* / Q000378:metabolism; D010100:Oxygen / Q000737:chemistry; D011622:Pterins / Q000737:chemistry / Q000378:metabolism; D013055:Spectrophotometry, Infrared
chemical_list: D019843:Archaeal Proteins; D002247:Carbon Isotopes; D003486:Cyanides; D058085:Iron Compounds; C091917:N(5),N(10)-methylene-tetrahydromethanopterin; D011622:Pterins; D002248:Carbon Monoxide; D006859:Hydrogen; D000587:Oxidoreductases Acting on CH-NH Group Donors; C047126:methylenetetrahydromethanopterin dehydrogenase; D010100:Oxygen