Molecular anatomy of 2-oxoacid : ferredoxin oxidoreductase from hyperthermophilic archaea

2-氧代酸：铁氧还蛋白氧化还原酶(OFOR)以铁氧还蛋白为电子受体，催化2-氧代酸氧化脱羧基。Ofor存在于所有古生菌、某些真细菌和某些真核生物中。Ofor的结构与功能的关系尚不清楚。这在一定程度上是因为构建产生稳定酶的基因表达系统的困难，或者是因为大多数来自厌氧生物的OFORs对氧的内在敏感性。在本研究中，我们首先构建了硫叶菊Ofor基因的表达系统。菌株7，比较了重组酶和天然重组酶的性质。根据迄今调查的标准，这两个OFOR是无法区分的。在基因表达系统的基础上，设计了一系列具有催化作用的突变体。其中一些失去了活性，另一些被发现改变了其底物专一性。

2-Oxoacid : ferredoxin oxidoreductase (OFOR) catalyzes oxidative decarboxylation of 2-oxoacids, using ferredoxin as an electron acceptor. The OFOR is found among all archaea, certain eubacteria, and certain eukaryotes. The structure-function relationship of OFOR is not clearly elucidated. This is partly because of the difficulty in constructing gene expression system that produces stable enzyme, or of the intrinsic oxygen-sensitivity of most OFORS from anaerobic organisms. In the present study, we first constructed the OFOR gene expression system from Sulfolobus sp. strain 7, compared the characteristics of recombinant enzyme with natural one. The two OFORs were indistinguishable by the criteria so far investigated. Based on the gene expression system, a series of mutants that is implicated as catalytic sites were designed. Some of them lost activity, and the other were found to change its substrate specificity.