McGuirl M A, Nelson L K, Bollinger J A, Chan Y K, Dooley D M
Department of Chemistry and Biochemistry, Montana State University, Bozeman 59717, USA.
J Inorg Biochem. 1998 Jul;70(3-4):155-69. doi: 10.1016/s0162-0134(98)10001-6.
The nitrous oxide (N2O) reductase (nos) gene cluster from Achromobacter cycloclastes has been cloned and sequenced. Seven protein coding regions corresponding to nosR, nosZ (structural N2O reductase gene), nosD, nosF, nosY, nosL, and nosX are detected, indicating a genetic organization similar to that of Rhizobium meliloti. To aid homology studies, nosR from R. meliloti has also been sequenced. Comparison of the deduced amino acid sequences with corresponding sequences from other organisms has also allowed structural and functional inferences to be made. The heterologous expression of NosD, NosZ (N2O reductase), and NosL is also reported. A model of the CuA site in N2O reductase, based on the crystal structure of this site in bovine heart cytochrome c oxidase, is presented. The model suggests that a His residue of the CuA domain may be a ligand to the catalytic CuZ site. In addition, the origin of the spectroscopically-observed Cys coordination to CuZ is discussed in terms of the sequence alignment of seven N2O reductases.
已克隆并测序了来自解环无色杆菌的一氧化二氮（N₂O）还原酶（nos）基因簇。检测到七个与nosR、nosZ（结构性N₂O还原酶基因）、nosD、nosF、nosY、nosL和nosX相对应的蛋白质编码区，这表明其基因组织与苜蓿根瘤菌的相似。为了辅助同源性研究，还对苜蓿根瘤菌的nosR进行了测序。将推导的氨基酸序列与其他生物体的相应序列进行比较，也有助于进行结构和功能推断。本文还报道了NosD、NosZ（N₂O还原酶）和NosL的异源表达。基于牛心细胞色素c氧化酶中该位点的晶体结构，提出了N₂O还原酶中CuA位点的模型。该模型表明，CuA结构域的一个组氨酸残基可能是催化性CuZ位点的配体。此外，根据七种N₂O还原酶的序列比对，讨论了光谱观察到的半胱氨酸与CuZ配位的起源。
