Cationic Copolymers Act As Chaperones of a Membrane-Active Peptide: Influence on Membrane Selectivity
Cationic Copolymers Act As Chaperones of a Membrane-Active Peptide: Influence on Membrane Selectivity
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阳离子共聚物作为膜活性肽的伴侣：对膜选择性的影响
DOI：
10.1021/acsbiomaterials.8b01582
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发表时间：
2019
影响因子：
5.8
通讯作者：
Maruyama Atsushi
中科院分区：
文献类型：
--
作者：
Sakamoto Wakako;Masuda Tsukuru;Ochiai Takuro;Shimada Naohiko;Maruyama Atsushi
膜活性肽具有作为控制细胞和脂质体中脂质双层结构的药物递送工具的潜力。在以前的研究中，我们报道了一种阳离子梳型共聚物，聚（烯丙胺）-接枝-葡聚糖（PAA-g-Dex），形成一个可溶性的插入复合物与阴离子肽，E5，并提高其膜破坏活性。此外，E5/PAA-g-Dex复合物增加了其他蛋白质的细胞膜渗透性。在这项研究中，E5/PAA-g-Dex复合物的各种组合物的脂质膜的亲和力进行了测定。E5的二级结构分析和E5与脂质体结合的分析表明，脂质组成强烈影响相互作用。在pH 5.4或pH 7.4下均未观察到单独E5的显著折叠，并且仅在pH 5.4下在具有液体无序相（Ld）的脂质体的存在下观察到折叠成N-末端和C-末端螺旋的功能构象。PAA-g-Dex在pH 5.4和pH 7.4下诱导E5的部分折叠，推测在C-末端。E5折叠成功能性结构是通过加入在pH 5.4或pH 7.4下具有Ld相的脂质体来诱导的。渗漏实验表明PAA-g-Dex通过促进E5在脂质体表面的吸附和/或E5与脂质双层的结合来增强E5的膜透化活性。这些结果表明，PAA-g-Dex激活的E5使具有Ld相的脂质膜不稳定，即使当脂质膜具有非均相分离结构时。因此，PAA-g-Dex可作为E5的分子伴侣，而不改变其膜选择性。这种梳型共聚物的伴侣活性可以激活其他结构不稳定和低溶解度的离子肽。
Membrane-active peptides have potential as drug delivery tools for control of lipid bilayer structures in cells and liposomes. In a previous study, we reported that a cationic comb-type copolymer, poly(allylamine)-graft-dextran (PAA-g-Dex), forms a soluble interpolyelectrolyte complex with an anionic peptide, E5, and enhances its membrane-disrupting activity. Furthermore, the E5/PAA-g-Dex complex augments the cellular membrane permeability of other proteins. In this study, the affinities of the E5/PAA-g-Dex complex for lipid membranes with various compositions were determined. Secondary structure analysis of E5 and analyses of binding of E5 to liposomes revealed that lipid composition strongly influenced the interaction. No significant folding of E5 alone was observed at either pH 5.4 or pH 7.4 and folding into the functional conformation, which is both N-terminal and C-terminal helix, was observed only at pH 5.4 in the presence of liposomes having liquid-disordered phase (Ld). PAA-g-Dex induced partial folding of E5, presumably at C-terminus, at both pH 5.4 and pH 7.4. Folding of E5 into the functional structure was induced by the addition of liposomes havingLdphases at either pH 5.4 or pH 7.4. A leakage assay showed that PAA-g-Dex enhanced the membrane-permeabilizing activity of E5 by promoting the adsorption of E5 onto the surface of liposomes and/or E5 association with the lipid bilayer. These results indicated that E5 activated by PAA-g-Dex destabilizes the lipid membrane havingLdphase even when the lipid membrane has a heterogeneous phase separated structure. Hence, PAA-g-Dex serves as a chaperone for E5 without altering its membrane selectivity. The chaperoning activity of this comb-type copolymer may activate other ionic peptides with unstable structures and low solubility.