de Vries S, Schröder I
Department of Biotechnology, Delft University of Technology, 2628 BC Delft, The Netherlands.
Biochem Soc Trans. 2002 Aug;30(4):662-7. doi: 10.1042/bst0300662.
The denitrification pathway has been studied in the hyperthermophilic archaeon Pyrobaculum aerophilum. In contrast with Gram-negative bacteria, all four denitrification enzymes are membrane-bound. P. aerophilum is also the only denitrifyer identified so far in which menaquinol is the electron donor to all four denitrification reductases. The NO reductase (NOR) of P. aerophilum belongs to the superfamily of haem-copper oxidases and is of the qNOR (quinol-dependent) type. Three types of NOR have been purified so far: cNOR (cytochrome c/pseudoazurin-dependent), qNOR and qCu(A)NOR (qNOR that contains Cu(A) at the electron entry site). It is proposed that the NORs and the various cytochrome oxidases have evolved by modular evolution, in view of the structure of their electron donor sites. qNOR is further proposed to be the ancestor of all NORs and cytochrome oxidases belonging to the superfamily of haem-copper oxidases.
已对嗜热古菌嗜气栖热袍菌中的反硝化途径进行了研究。与革兰氏阴性细菌不同，所有四种反硝化酶都与膜结合。嗜气栖热袍菌也是迄今为止鉴定出的唯一一种以甲萘醌作为所有四种反硝化还原酶电子供体的反硝化菌。嗜气栖热袍菌的一氧化氮还原酶（NOR）属于血红素 - 铜氧化酶超家族，是qNOR（依赖于醌醇）类型。迄今为止已纯化出三种类型的NOR：cNOR（依赖于细胞色素c/假天青蛋白）、qNOR和qCu(A)NOR（在电子进入位点含有Cu(A)的qNOR）。鉴于其电子供体位点的结构，有人提出NOR和各种细胞色素氧化酶是通过模块进化而来的。进一步有人提出qNOR是属于血红素 - 铜氧化酶超家族的所有NOR和细胞色素氧化酶的祖先。
