The periplasmic nitrate reductase in Shewanella: the resolution, distribution and functional implications of two NAP isoforms, NapEDABC and NapDAGHB.
The periplasmic nitrate reductase in Shewanella: the resolution, distribution and functional implications of two NAP isoforms, NapEDABC and NapDAGHB.
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DOI：
10.1099/mic.0.034421-0
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发表时间：
2010-02
期刊：
影响因子：
1.5
通讯作者：
P. Simpson;D. Richardson;R. Codd
中科院分区：
文献类型：
--
作者：
P. Simpson;D. Richardson;R. Codd
在细菌周围质中，硝酸盐还原为亚硝酸盐是由周围质硝酸盐还原酶（NAP）系统催化的，该系统是由NAP操纵子编码的蛋白质亚基的物种依赖性组装。NAP催化的硝酸还原发生在90 kDa的NapA亚基中，该亚基包含一个钼-双钼鸟嘌呤二核苷酸辅因子和一个[4Fe-4S]铁硫团簇。对19株希瓦氏菌基因组中午睡操纵子的分析表明，大多数希瓦氏菌基因组包含两个午睡操纵子。这是这个属的一个不寻常的特征。这两种NAP亚型分别包含三个亚型特异性亚基——NapA、二血红素细胞色素NapB和成熟伴侣蛋白NapD，但它们具有不同的膜内亚基，并被命名为NAP- α (NapEDABC)和NAP- β (NapDAGHB)。16个希瓦氏菌基因组同时编码nap - α和nap - β。活力反硝化菌Shewanella反硝化菌OS217的基因组只编码nap - α，而呼吸硝态氨化菌Shewanella oneidensis MR-1的基因组只编码nap - β。这就提出了一种可能性，即在环境适应性强的希瓦氏菌属中，nap - α和nap - β与生理上不同的过程有关。
In the bacterial periplasm, the reduction of nitrate to nitrite is catalysed by a periplasmic nitrate reductase (NAP) system, which is a species-dependent assembly of protein subunits encoded by the nap operon. The reduction of nitrate catalysed by NAP takes place in the 90 kDa NapA subunit, which contains a Mo-bis-molybdopterin guanine dinucleotide cofactor and one [4Fe-4S] iron-sulfur cluster. A review of the nap operons in the genomes of 19 strains of Shewanella shows that most genomes contain two nap operons. This is an unusual feature of this genus. The two NAP isoforms each comprise three isoform-specific subunits - NapA, a di-haem cytochrome NapB, and a maturation chaperone NapD - but have different membrane-intrinsic subunits, and have been named NAP-alpha (NapEDABC) and NAP-beta (NapDAGHB). Sixteen Shewanella genomes encode both NAP-alpha and NAP-beta. The genome of the vigorous denitrifier Shewanella denitrificans OS217 encodes only NAP-alpha and the genome of the respiratory nitrate ammonifier Shewanella oneidensis MR-1 encodes only NAP-beta. This raises the possibility that NAP-alpha and NAP-beta are associated with physiologically distinct processes in the environmentally adaptable genus Shewanella.