de Crouy-Chanel A, Kohiyama M, Richarme G
Institut Jacques Monod, Université Paris, France.
J Biol Chem. 1995 Sep 29;270(39):22669-72. doi: 10.1074/jbc.270.39.22669.
Molecular chaperones, protein-disulfide isomerases, and peptidyl prolyl cis-trans isomerases assist protein folding in both prokaryotes and eukaryotes. The DnaJ protein of Escherichia coli and the DnaJ-like proteins of eukaryotes are known as molecular chaperones and specific regulators of DnaK-like proteins and are involved in protein folding and renaturation after stress. In this study we show that DnaJ, like thioredoxin, protein-disulfide isomerase, and DsbA, possesses an active dithiol/disulfide group and catalyzes protein disulfide formation (oxidative renaturation of reduced RNase), reduction (reduction of insulin disulfides), and isomerization (refolding of randomly oxidized RNase). These results suggest that, in addition to its known function as a chaperone, DnaJ might be involved in controlling the redox state of cytoplasmic, membrane, or exported proteins.
分子伴侣、蛋白质二硫键异构酶和肽基脯氨酰顺反异构酶在原核生物和真核生物中都协助蛋白质折叠。大肠杆菌的DnaJ蛋白和真核生物的类DnaJ蛋白被认为是分子伴侣以及DnaK样蛋白的特异性调节因子，并且参与应激后的蛋白质折叠和复性。在本研究中，我们表明DnaJ与硫氧还蛋白、蛋白质二硫键异构酶和DsbA一样，具有活性二硫醇/二硫键基团，并催化蛋白质二硫键的形成（还原型核糖核酸酶的氧化复性）、还原（胰岛素二硫键的还原）和异构化（随机氧化的核糖核酸酶的重折叠）。这些结果表明，除了其作为伴侣蛋白的已知功能外，DnaJ可能还参与控制细胞质、膜或分泌蛋白的氧化还原状态。
