title: The crystal structure of C176A mutated [Fe]-hydrogenase suggests an acyl-iron ligation in the active site iron complex.
abstract: [Fe]-hydrogenase is one of three types of enzymes known to activate H(2). Crystal structure analysis recently revealed that its active site iron is ligated square-pyramidally by Cys176-sulfur, two CO, an "unknown" ligand and the sp(2)-hybridized nitrogen of a unique iron-guanylylpyridinol-cofactor. We report here on the structure of the C176A mutated enzyme crystallized in the presence of dithiothreitol (DTT). It suggests an iron center octahedrally coordinated by one DTT-sulfur and one DTT-oxygen, two CO, the 2-pyridinol's nitrogen and the 2-pyridinol's 6-formylmethyl group in an acyl-iron ligation. This result led to a re-interpretation of the iron ligation in the wild-type.
authors.affiliation: Max-Planck-Institut für Terrestrische Mikrobiologie, Marburg, Germany.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Hiromoto
authors.forename: Kenichi
authors.initials: K
authors.lastname: Ataka
authors.forename: Oliver
authors.initials: O
authors.lastname: Pilak
authors.forename: Sonja
authors.initials: S
authors.lastname: Vogt
authors.forename: Marco Salomone
authors.initials: MS
authors.lastname: Stagni
authors.forename: Wolfram
authors.initials: W
authors.lastname: Meyer-Klaucke
authors.forename: Eberhard
authors.initials: E
authors.lastname: Warkentin
authors.forename: Rudolf K
authors.initials: RK
authors.lastname: Thauer
authors.forename: Seigo
authors.initials: S
authors.lastname: Shima
authors.forename: Ulrich
authors.initials: U
authors.lastname: Ermler
mesh_terms: D000225:Adenine / Q000378:metabolism; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D003596:Cytosine / Q000378:metabolism; D020035:Holoenzymes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D006864:Hydrogenase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D007501:Iron / Q000737:chemistry* / Q000378:metabolism*; D007506:Iron-Sulfur Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D017015:Methanococcales / Q000201:enzymology / Q000235:genetics; D009154:Mutation / Q000235:genetics; D020836:Protein Structure, Quaternary
chemical_list: D020035:Holoenzymes; D007506:Iron-Sulfur Proteins; D003596:Cytosine; D007501:Iron; C118830:iron hydrogenase; D006864:Hydrogenase; D000225:Adenine