Shima Seigo, Thauer Rudolf K, Ermler Ulrich
Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Strasse, D-35043 Marburg, Germany
Met Ions Life Sci. 2009;6:219-40. doi: 10.1039/BK9781847559159-00219. Epub 2009 Jan 30.
Structural and spectroscopic studies on [Fe]-hydrogenase revealed an active site mononuclear low spin iron coordinated by the Cys176 sulfur, two CO, and the sp(2) hybridized nitrogen of a 2-pyridinol compound with back bonding properties similar to those of cyanide. Thus, [Fe]-hydrogenases are endowed with an iron-ligation pattern related to that found in the active site of [NiFe]- and [FeFe]-hydrogenases although the three hydrogenases and the enzymes involved in their posttranslational maturation have evolved independently and although CO and cyanide ligands are not found in any other metallo-enzymes. Obviously, low-spin iron complexed with thiolate(s), CO, and cyanide or a cyanide functional analogue plays an essential role in H(2) activation.
对[铁]氢化酶的结构和光谱研究表明，其活性位点为单核低自旋铁，由半胱氨酸176的硫原子、两个一氧化碳以及具有与氰化物类似的反馈键性质的2-吡啶醇化合物的sp(2)杂化氮原子配位。因此，[铁]氢化酶具有与[镍铁]氢化酶和[铁铁]氢化酶活性位点中发现的铁配位模式相关的模式，尽管这三种氢化酶及其翻译后成熟过程中涉及的酶是独立进化的，并且尽管在任何其他金属酶中都未发现一氧化碳和氰化物配体。显然，与硫醇盐、一氧化碳和氰化物或氰化物功能类似物络合的低自旋铁在氢气活化中起着至关重要的作用。
