毒素蛋白Colicin E1与磷脂膜的相互作用

多肽及蛋白质的插膜机制是目前分子生物学、细胞生物学研究中十分活跃的领域之一。本文通过荧光、圆二色等波谱学技术，深入地探讨了处于不同构象状态的毒素蛋白分子与磷脂膜作用后的构象变化。结果表明：带负电荷的磷脂膜对处于不同构象状态的ＣｏｌｉｃｉｎＥ１分子的二级结构有较强的诱导作用；这种作用是电荷依赖性的。处于不同构象状态的毒素蛋白分子在磷脂膜的诱导下均可不同程度恢复其天然状态下插膜时的构象。不同磷脂对ＣｏｌｉｃｉｎＥ１分子诱导的强弱依次为ＤＭＰＧ＞ＤＭＰＥ＞ＤＭＰＣ。ＣｏｌｉｃｉｎＥ１分子与磷脂膜的结合是紧密的，结合后的蛋白质有较强的抗变性能力。

Interaction of Colicin E_1 with Lipid Membranes

In order to gain an insight into the mechanism of membrane insertion of the pore-forming protein colicin E1 and the siructure of its membrane-bound form,circular dichroism,fluoresoence spectroscopy experiments were carried out.The results revealed the law of conformational changes by lipld membrane induction of the colicin E1 molecule,and suggest that the lipid membranes with negative charges have a strong inducing action on colicin E1 molecules.With the induction of membrane,the colicin E1 molecules in different conformational states can all be recovered to the conformation of membrane insertion in native state.The induction intensity of different kinds of lipids on colicin E1 was in the following order:DMPG>DMPE>DMPC.The binding of colic in E1 with lipid vesicles was tight and the membrane-bound proteins were resistant to denaturation.