Functional analysis of paralogous thiol-disulfide oxidoreductases in Bacillus subtilis
Functional analysis of paralogous thiol-disulfide oxidoreductases in Bacillus subtilis
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DOI：
10.1074/jbc.274.35.24531
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发表时间：
1999-08-27
影响因子：
4.8
通讯作者：
van Dijl, JM
中科院分区：
文献类型：
--
作者：
Bolhuis, A;Venema, G;van Dijl, JM
二硫键的体内形成对于许多蛋白质的稳定性和/或活性至关重要，由硫醇二硫键氧化还原酶催化。在本研究中，我们发现革兰氏阳性真细菌枯草芽孢杆菌含有三个硫醇二硫键氧化还原酶基因，分别表示为bdbA、bdbB和bdbC，大肠杆菌碱性磷酸酶含有两个二硫键，当由缺乏BdbB或BdbC的枯草芽孢杆菌细胞分泌时不稳定，值得注意的是，bdbB和bdbC的表达水平似乎设定了限制为了分泌活性碱性磷酸酶，缺乏 BdbC 的细胞还表现出细胞相关形式的大肠杆菌 TEM-β-内酰胺酶（含有一个二硫键）的稳定性降低。相比之下，碱性磷酸酶或 β-内酰胺酶的稳定性不需要 BdbA。由于 BdbB 和 BdbC 是典型的膜蛋白，因此我们的研究结果表明它们促进膜-细胞壁界面处的蛋白质折叠。有趣的是，在缺乏 BdbC 的细胞中刺激前 β-内酰胺酶加工成成熟形式，这表明该前体的未折叠形式是信号肽酶的首选底物。令人惊讶的是，缺乏 BdbC 的细胞没有形成摄取 DNA 的能力，这表明含有二硫键的蛋白质参与了这一过程。与大肠杆菌和酵母不同，枯草芽孢杆菌的硫醇二硫化物氧化还原酶不需要还原剂存在下的生长。总之，我们的观察表明 BdbB 和 BdbC 在二硫键形成中具有一般作用，而 BdbA 可能专用于特定过程。
The in vivo formation of disulfide bonds, which is critical for the stability and/or activity of many proteins, is catalyzed by thiol-disulfide oxidoreductases. In the present studies, we show that the Gram-positive eubacterium Bacillus subtilis contains three genes, denoted bdbA, bdbB, and bdbC, for thiol-disulfide oxidoreductases, Escherichia coli alkaline phosphatase, containing two disulfide bonds, was unstable when secreted by B. subtilis cells lacking BdbB or BdbC, and notably, the expression levels of bdbB and bdbC appeared to set a limit for the secretion of active alkaline phosphatase, Cells lacking BdbC also showed decreased stability of cell-associated forms of E. coli TEM-beta-lactamase, containing one disulfide bond. In contrast, BdbA was not required for the stability of alkaline phosphatase or beta-lactamase. Because BdbB and BdbC are typical membrane proteins, our findings suggest that they promote protein folding at the membrane-cell wall interface. Interestingly, pre-beta-lactamase processing to its mature form was stimulated in cells lacking BdbC, suggesting that the unfolded form of this precursor is a preferred substrate for signal peptidase. Surprisingly, cells lacking BdbC did not develop competence for DNA uptake, indicating the involvement of disulfide bond-containing proteins in this process. Unlike E. coli and yeast, none of the thiol-disulfide oxidoreductases of B, subtilis was required for growth in the presence of reducing agents. In conclusion, our observations indicate that BdbB and BdbC have a general role in disulfide bond formation, whereas BdbA may be dedicated to a specific process.