The crystal structure of C176A mutated [Fe]-hydrogenase suggests an acyl-iron ligation in the active site iron complex.
[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.
Hiromoto
Takeshi
T
Max-Planck-Institut für Terrestrische Mikrobiologie, Marburg, Germany.
Ataka
Kenichi
K
Pilak
Oliver
O
Vogt
Sonja
S
Stagni
Marco Salomone
MS
Meyer-Klaucke
Wolfram
W
Warkentin
Eberhard
E
Thauer
Rudolf K
RK
Shima
Seigo
S
Ermler
Ulrich
U
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
D020035:Holoenzymes; D007506:Iron-Sulfur Proteins; D003596:Cytosine; D007501:Iron; C118830:iron hydrogenase; D006864:Hydrogenase; D000225:Adenine