Identification of a segment of DsbB essential for its respiration‐coupled oxidation
Identification of a segment of DsbB essential for its respiration‐coupled oxidation
复制标题
鉴定对其呼吸耦合氧化至关重要的 DsbB 片段
作者：
Taeko Kobayashi;Yuki Takahashi;Koreaki Ito
在大肠杆菌蛋白二硫键形成途径中，膜结合的DsbB氧化周质DsbA，二硫键引入酶。DsbB的第一周质结构域中的Cys-41-Val-Leu-Cys-44基序通过细胞的呼吸功能保持强烈氧化。我们现在表明，即使当侧翼的Val-Leu组合被来自其他氧化还原酶的XX序列取代时，Cys-41-Cys-44键的特征性二硫苏糖醇抗性也被保留。插入突变的结果表明，只有在C末端邻近CXXC基序的区域中的插入（1-31个氨基酸）损害了DsbB的氧化态。从该区域缺失单个氨基酸也使DsbB减少和失活。然而，CXXC和跨膜片段侧翼的四个残基的单个氨基酸取代并没有废除DsbB的氧化。这些结果表明，一些物理性质，如CXXC基序与膜的距离，对DsbB的呼吸偶联氧化很重要。
In the Escherichia coli protein disulphide bond formation pathway, membrane‐bound DsbB oxidizes periplasmic DsbA, the disulphide bond‐introducing enzyme. The Cys‐41–Val–Leu–Cys‐44 motif in the first periplasmic domain of DsbB is kept strongly oxidized by the respiratory function of the cell. We now show that the characteristic dithiothreitol resistance of the Cys‐41–Cys‐44 bond was retained even when the flanked Val–Leu combination was replaced by XX sequences from other oxidoreductases. Results of insertion mutagenesis showed that only the insertions (1–31 amino acids) in the region C‐terminally adjacent to the CXXC motif impaired the oxidized state of DsbB. Deletion of a single amino acid from this region also rendered DsbB reduced and inactive. However, single amino acid substitutions of the four residues flanked by CXXC and the transmembrane segment did not abolish the oxidation of DsbB. These results suggest that some physical property, such as distance of the CXXC motif from the membrane, is important for the respiration‐coupled oxidation of DsbB.
蛋白质中允许位点的简单筛选：大肠杆菌乳胶通透酶分析。
DOI：
10.1006/jmbi.1996.0881
发表时间：
1997
期刊：
Journal of molecular biology.
影响因子：
--
作者：
Manoil,C;Bailey,J
通讯作者：
Bailey,J