In situ unfolded lysozyme induces the lipid lateral redistribution of a mixed lipid model membrane.
In situ unfolded lysozyme induces the lipid lateral redistribution of a mixed lipid model membrane.
复制标题
DOI：
10.1021/jp304339t
复制
发表时间：
2012-10
期刊：
影响因子：
--
通讯作者：
Jun-jie Luo;Fulin Wu;S. Qin;Zhi‐Wu Yu
中科院分区：
文献类型：
--
作者：
Jun-jie Luo;Fulin Wu;S. Qin;Zhi‐Wu Yu
聚电解质引起的带电脂质的再分布是一个有趣的现象。蛋白质，由于其作为聚电解质的性质，也应该具有这种能力。但它们高度有序的结构可能带来更复杂的机制。研究了中性二棕榈酰磷脂酰胆碱（DPPC）和带负电荷的二油酰磷脂酰甘油（DOPG）组成的脂质体与溶菌酶的相互作用。有趣的是，DOPG的富集不能由天然和异位未折叠（在不存在脂质体的情况下未折叠）溶菌酶诱导，而是需要溶菌酶经历原位未折叠过程（在存在脂质体的情况下未折叠）。这些观察结果表明，对于蛋白质，诱导脂质再分布的能力不仅依赖于净电荷，而且依赖于电荷的空间分布。在原位解折叠过程中，溶菌酶将其结构重组为富含平坦β-折叠的特殊解折叠结构，并且在脂质膜存在下更“刚性”。这种特殊的空间结构改变了电荷分布，有利于蛋白质与膜的静电相互作用，从而引起脂质的再分布。
Redistribution of charged lipids induced by polyelectrolytes is an intriguing phenomenon. Proteins, due to their nature as polyelectrolytes, should also have this capacity. But their highly ordered structures may bring about more complex mechanisms. We studied the interaction between positively charged lysozyme and liposomes consisting of neutral dipalmitoylphosphatidylcholine (DPPC) and negatively charged dioleoylphosphatidylglycerol (DOPG). Interestingly, the enrichment of DOPG cannot be induced by the native and ex situ unfolded (unfolded in the absence of liposomes) lysozyme, but requires that lysozyme undergo an in situ unfolding process (unfolding in the presence of liposomes). These observations suggest that, for proteins, the capacity to induce lipid redistribution relies on not only the net charges but also the spatial distribution of the charges. During the in situ unfolding process, lysozyme reorganizes its structure into a specially unfolded structure that is rich in flat β-sheets and more "rigid" in the presence of lipid membrane. This special spatial structure changes the charge distribution and is advantageous to the protein-membrane electrostatic interaction and thus can induce lipid redistribution.