Dornmair K, Kiefer H, Jähnig F
Max-Planck-Institut für Biologie, Tübingen, West Germany.
J Biol Chem. 1990 Nov 5;265(31):18907-11.
OmpA is an integral membrane protein from the outer membrane of Escherichia coli. Purified, lipopolysaccharide-free OmpA was denatured by boiling in sodium dodecyl sulfate (SDS). Refolding was then induced by replacement of SDS with the nonionic detergent octylglucoside. The structure of both the denatured and refolded protein were investigated by SDS-gel electrophoresis, protease digestion, Raman and fluorescence spectroscopy. Refolded OmpA could be reconstituted into membranes of the synthetic lipid dimyristoylphosphatidylcholine. Thus, lipopolysaccharide is neither necessary for proper folding of OmpA nor for its insertion into lipid membranes. Based on this result, models for sorting of OmpA into the outer membrane of E. coli are discussed.
OmpA是一种来自大肠杆菌外膜的整合膜蛋白。纯化后的无脂多糖OmpA在十二烷基硫酸钠（SDS）中煮沸而变性。然后通过用非离子去污剂辛基葡糖苷替代SDS来诱导复性。通过SDS-凝胶电泳、蛋白酶消化、拉曼光谱和荧光光谱研究了变性和复性蛋白的结构。复性后的OmpA可以重新组装到合成脂质二肉豆蔻酰磷脂酰胆碱的膜中。因此，脂多糖对于OmpA的正确折叠及其插入脂质膜既不是必需的。基于这一结果，讨论了OmpA分选到大肠杆菌外膜中的模型。
