X-ray structural study of the membrane-bound[NiFe]-hydrogenase

氢化酶通过催化分子氢的合成和分解在氢代谢中起着关键作用。虽然大多数氢化酶在O2存在下不表现出活性，但膜结合的[NiFe]-氢化酶已知是耐O2的，其机制知之甚少。在这项研究中，X-射线晶体结构的膜结合[NiFe]-氢化酶已被确定为三种不同的氧化还原状态在1.2-1.4 A的分辨率。其中一个Fe-S簇表现出前所未有的结构和氧化还原依赖的构象变化，这应该归因于该氢化酶的耐氧性能。

Hydrogenases play key roles in hydrogen metabolism by catalyzing synthesis and decomposition of molecular hydrogen. While most of the hydrogenases exhibit no activity in the presence of O2, the membrane-bound[NiFe]-hydrogenase is known to be O2-tolerant, of which mechanism had been poorly understood. In this study, X-ray crystal structures of the membrane-bound[NiFe]-hydrogenase have been determined for three different redox states at resolutions of 1.2-1.4 A. One of the Fe-S clusters showed an unprecedented structure and its redox dependent conformational changes, to which the O2-tolerant property of this hydrogenase should be ascribable.