Saraste M, Castresana J
European Molecular Biology Laboratory, Heidelberg, Germany.
FEBS Lett. 1994 Mar 14;341(1):1-4. doi: 10.1016/0014-5793(94)80228-9.
The cytochrome bc complex which is encoded by the fixNOPQ operon in Bradyrhizobium japonicum, is the most distant member of the haem-copper cytochrome oxidase family. We have found that its major subunit, FixN, is homologous to the NorB subunit of nitric oxide reductase in a purple bacterium. A second evolutionary link between cytochrome oxidases and denitrification enzymes is the presence of a similar binuclear copper site in cytochrome aa3 (the mitochondrial oxidase) and nitrous oxide reductase. This centre was probably acquired by a primitive FixN-type oxidase, leading to the evolution of the mitochondrial-type oxidase. These links suggest that the oxygen-reducing respiratory chain developed from the anaerobic, denitrifying respiratory system.
由日本慢生根瘤菌中的fixNOPQ操纵子编码的细胞色素bc复合物，是血红素-铜细胞色素氧化酶家族中亲缘关系最远的成员。我们发现其主要亚基FixN与紫色细菌中一氧化氮还原酶的NorB亚基同源。细胞色素氧化酶和反硝化酶之间的第二个进化联系是细胞色素aa3（线粒体氧化酶）和一氧化二氮还原酶中存在类似的双核铜位点。这个中心可能是由原始的FixN型氧化酶获得的，从而导致了线粒体型氧化酶的进化。这些联系表明，氧还原呼吸链是从厌氧的反硝化呼吸系统发展而来的。
