Modulating the structure and interactions of lipid-peptide complexes by varying membrane composition and solution conditions
Modulating the structure and interactions of lipid-peptide complexes by varying membrane composition and solution conditions
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DOI：
10.1039/c3sm00105a
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发表时间：
2013-01-01
期刊：
影响因子：
3.4
通讯作者：
Raviv, Uri
中科院分区：
文献类型：
--
作者：
Moshe, Leora;Saper, Gadiel;Raviv, Uri
膜和肽之间的相互作用取决于肽的详细结构、脂质组成和膜结构。在这里，我们研究了脂质膜与短肽的相互作用，短肽在一定条件下可以穿透细胞。利用溶液x射线散射，我们研究了肽Ac-Gly-Phe-D-Phe-Arg-Trp-Gly-NH2与多种脂质膜混合时形成的结构。我们研究了含有不同性质的脂质混合物如何控制相互作用，从而控制产生的脂质-肽复合物的结构。我们发现，在一个临界浓度下，肽与脂质双分子层结合并使膜变薄。对于低于0.75和高于某个临界肽浓度的带电荷脂质的一小部分，肽可以桥接带电荷的膜。此外，肽可以给两性离子DOPC膜充电，或将DOPC脂质的倒六边形相转化为多层相。我们将这些观察结果归因于疏水、静电、熵和空间效应之间的平衡，这些效应与肽和膜的特定结构有关。肽的两个短的疏水部分有利于膜的疏水部分，而它的带电氨基酸（Arg），位于中间，更喜欢水环境。研究人员仔细研究了膜电荷密度、自发曲率、脂质填充参数以及溶液条件，并在一致的框架下对这些组件进行了全面的了解。
The interactions between membranes and peptides depend on the detailed peptides' structure, lipid composition, and membrane structure. Here, we study the interaction of lipid membrane with a short peptide, which under certain conditions may penetrate cells. Using solution X-ray scattering, we investigated the structures that form when mixing the peptide Ac-Gly-Phe-D-Phe-Arg-Trp-Gly-NH2 with a variety of lipid membranes. We studied how lipid mixtures, containing lipids with different properties, control the interactions and, thereby the structures of the resulting lipid-peptide complexes. We found that below a critical concentration the peptides associate with the lipid bilayers and thin the membranes. For a fraction of charged lipids below 0.75 and above some critical peptide concentration, the peptide can bridge like-charged membranes. Moreover, the peptide can charge zwitterionic DOPC membranes, or convert the inverted hexagonal phase of the DOPE lipid into a multilamellar phase. We attribute these observations to a balance between hydrophobic, electrostatic, entropic, and steric effects, associated with the specific structures of the peptide and membranes. The two short hydrophobic moieties of the peptide favor the hydrophobic part of the membranes, whereas its charged amino acid (Arg), situated in the middle, prefers the aqueous environment. The membrane charge density, spontaneous curvature, lipid packing parameter, as well as solution conditions were carefully studied and allow a comprehensive understanding of these assemblies under a consistent framework.