Hiromoto Takeshi, Ataka Kenichi, Pilak Oliver, Vogt Sonja, Stagni Marco Salomone, Meyer-Klaucke Wolfram, Warkentin Eberhard, Thauer Rudolf K, Shima Seigo, Ermler Ulrich
Max-Planck-Institut für Terrestrische Mikrobiologie, Marburg, Germany.
FEBS Lett. 2009 Feb 4;583(3):585-90. doi: 10.1016/j.febslet.2009.01.017. Epub 2009 Jan 20.
[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.
[铁]氢化酶是已知的三种能激活氢气的酶之一。晶体结构分析最近表明，其活性位点的铁由半胱氨酸176的硫、两个一氧化碳、一个“未知”配体以及独特的铁-鸟苷基吡啶醇辅因子的sp(2)杂化氮以方锥形式配位。我们在此报告在二硫苏糖醇（DTT）存在下结晶的C176A突变酶的结构。它表明铁中心由一个DTT的硫和一个DTT的氧、两个一氧化碳、2-吡啶醇的氮以及酰基铁配位中2-吡啶醇的6-甲酰甲基以八面体形式配位。这一结果导致了对野生型中铁配位的重新解释。
