Kembi F, Harrington M A
Department of Biology, Delaware State University, 1200 DuPont Highway, Dover, Delaware 19901, USA.
Biochem Biophys Res Commun. 2001 Nov 9;288(4):819-26. doi: 10.1006/bbrc.2001.5848.
Gating of the cystic fibrosis transmembrane conductance regulator (CFTR) channels requires interdomain and/or intermolecular interactions involving different parts of the protein, yet the exact nature of those interactions remains unclear. In this study we report that treating wild type CFTR-expressing cells with oxidizing agents results in a significant reduction in the gel mobility of the protein indicative of the formation of disulfide bonds. In contrast, mutant CFTR channels in which cysteine residues in both nucleotide binding domains (NBDs) were mutated to serine, showed little change in gel mobility in oxidizing conditions. Mutation of the two cysteine residues in either the first or the second NBD alone also eliminates the change in gel mobility in oxidizing conditions. Wild type channels treated with oxidizing agents did not appear to form disulfide bonds with other proteins, suggesting that the close association that allows the formation of disulfide bonds occurs only within single proteins and not between separate channels interacting in a multimer.
囊性纤维化跨膜传导调节因子（CFTR）通道的门控需要涉及蛋白质不同部分的结构域间和/或分子间相互作用，然而这些相互作用的确切性质仍不清楚。在本研究中，我们报告用氧化剂处理表达野生型CFTR的细胞会导致蛋白质的凝胶迁移率显著降低，这表明形成了二硫键。相比之下，两个核苷酸结合结构域（NBD）中的半胱氨酸残基都突变为丝氨酸的突变型CFTR通道，在氧化条件下凝胶迁移率几乎没有变化。仅在第一个或第二个NBD中两个半胱氨酸残基的突变也消除了氧化条件下凝胶迁移率的变化。用氧化剂处理的野生型通道似乎没有与其他蛋白质形成二硫键，这表明允许形成二硫键的紧密结合仅发生在单个蛋白质内，而不是在多聚体中相互作用的单独通道之间。
