Characterization of a novel type of benzene ring reductase in Geobacter metallireducens

苯甲酰辅酶A是兼性厌氧细菌和严格厌氧细菌中厌氧芳香族代谢的关键中间体。兼性厌氧菌利用ATP依赖性环还原酶将苯甲酰基-CoA脱芳构化为双电子还原的环状二烯酰基-CoA化合物。在严格厌氧的模式生物Geetrium metallreducens中，苯甲酰辅酶A脱芳构化似乎也是通过还原来完成的，尽管ATP依赖性苯甲酰辅酶A还原酶的四个结构基因缺失。相反，我们的研究小组最近发现了8种迄今为止未知的蛋白质，它们由苯甲酸诱导的bamB-I基因编码。它们包括Mo-和硒代半胱氨酸-蛋白质的亚基，以及异二硫键还原酶和氢化酶样蛋白质，最可能形成复合物。本项目将首次研究严格厌氧模式生物苯环脱芳构化过程中各组分或推定酶复合体的组成和功能。将应用一些生物化学、免疫学、光谱学和电化学技术。所获得的结果应该揭示一种新的酶原理的见解。

Benzoyl-CoA is a key intermediate of anaerobic aromatic metabolism in both, facultatively and strictly anaerobic bacteria. Facultative anaerobes utilize an ATP-dependent ring reductase for the dearomatization of benzoyl-CoA to a two-electron reduced cyclic dienoyl-CoA compound. In the strictly anaerobic model organism Geobacter metallireducens, benzoyl-CoA dearomatization also appears to be accomplished by reduction, although the four structural genes of ATP-dependent benzoyl-CoA reductase are missing. Instead, eight so far unknown proteins, encoded by the benzoate-induced bamB-I genes, were recently identified by our group. They comprise subunits of Mo- and selenocysteine-proteins, and heterodisulfide reductases and hydrogenases-like proteins, most possibly forming a complex. In this project, the composition and function of the individual components/or the putative enzyme complex in benzene ring dearomatization of a strictly anaerobic model organism will be studied for the first time. A number of biochemical, immunological, spectroscopic and electrochemical techniques will be applied. The results obtained should reveal insights into a novel enzymatic principle.