Abstract For the first time, the functioning of the oxygen reductase Na + -pump (Na + -pumping cytochrome c oxidase of the cbb 3 -type) was demonstrated by examining the respiratory chain of the extremely alkaliphilic bacterium Thioalkalivibrio versutus [Muntyan, M. S., et al. (2015) Cytochrome cbb 3 of Thioalkalivibrio is a Na + -pumping cytochrome oxidase, Proc. Natl. Acad. Sci. USA , 112 , 7695-7700], a product of the ccoNOQP operon. In this study, we detected and identified this enzyme using rabbit polyclonal antibody against the predicted C-terminal amino acid sequence of its catalytic subunit. We found that this cbb 3 -type oxidase is synthesized in bacterial cells, where it is located in the membranes. The 48-kDa oxidase subunit (CcoN) is catalytic, while subunits CcoO and CcoP with molecular masses of 29 and 34 kDa, respectively, are cytochromes c . The theoretical p I values of the CcoN, CcoO, and CcoP subunits were determined. It was shown that parts of the CcoO and CcoP subunits exposed to the aqueous phase on the cytoplasmic membrane P-side are enriched with negatively charged amino acid residues, in contrast to the parts of the integral subunit CcoN adjacent to the aqueous phase. Thus, the Na + -pumping cytochrome c oxidase of T. versutus , both in function and in structure, demonstrates adaptation to extremely alkaline conditions.

中文翻译：

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极端嗜碱硫碱弧菌细菌膜中Na+泵送细胞色素氧化酶的鉴定

摘要 通过检查极端嗜碱性细菌 Thioalkalivibrio versutus 的呼吸链，首次证明了氧还原酶 Na + 泵（cbb 3 型的 Na + 泵送细胞色素 c 氧化酶）的功能 [Muntyan, MS,等。(2015) 硫碱弧菌的细胞色素 cbb 3 是一种 Na + 泵送细胞色素氧化酶，Proc。纳特尔。阿卡德。科学。USA , 112 , 7695-7700]，ccoNOQP 操纵子的产物。在本研究中，我们使用兔多克隆抗体对其催化亚基的预测 C 端氨基酸序列进行检测和鉴定。我们发现这种 cbb 3 型氧化酶是在细菌细胞中合成的，它位于细胞膜中。48-kDa 氧化酶亚基 (CcoN) 具有催化作用，而亚基 CcoO 和 CcoP 的分子量分别为 29 和 34 kDa，是细胞色素 c 。确定了 CcoN、CcoO 和 CcoP 亚基的理论 p I 值。结果表明，暴露于细胞质膜 P 侧水相的部分 CcoO 和 CcoP 亚基富含带负电荷的氨基酸残基，这与与水相相邻的整体亚基 CcoN 部分形成对比。因此，T. versutus 的 Na + 泵送细胞色素 c 氧化酶在功能和结构上都表现出对极端碱性条件的适应性。与与水相相邻的整体亚单元 CcoN 的部分相反。因此，T. versutus 的 Na + 泵送细胞色素 c 氧化酶在功能和结构上都表现出对极端碱性条件的适应性。与与水相相邻的整体亚单元 CcoN 的部分相反。因此，T. versutus 的 Na + 泵送细胞色素 c 氧化酶在功能和结构上都表现出对极端碱性条件的适应性。