Proline Facilitates Membrane Insertion of the Antimicrobial Peptide Maculatin 1.1 via Surface Indentation and Subsequent Lipid Disordering
Proline Facilitates Membrane Insertion of the Antimicrobial Peptide Maculatin 1.1 via Surface Indentation and Subsequent Lipid Disordering
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DOI：
10.1016/j.bpj.2013.01.059
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发表时间：
2013-04-02
影响因子：
3.4
通讯作者：
Separovic, Frances
中科院分区：
文献类型：
--
作者：
Fernandez, David I.;Lee, Tzong-Hsien;Separovic, Frances
研究了脯氨酸在抗菌肽(AMP)结合中膜双层结构破坏中的作用。特别是用P-31和H-2固体核磁共振和双极化干涉法(DPI)分析了三种AMPs的膜相互作用：斑蛋白1.1和两个类似物，其中Pro-15被甘氨酸和丙氨酸取代。在核磁共振方面，分别用双肉豆蔻基磷脂酰胆碱(d(54)-DMPC)和d(54)-DMPC/双肉豆蔻基磷脂酰甘油(DMPG)模拟真核膜和原核膜。在流体相DMPC双层体系中，多肽主要与双层表面相互作用，其中天然多肽的相互作用最强。在混合的DMPC/DMPG双层膜中，斑点蛋白1.1诱导DMPG相分离，而类似物促进各向同性相和富脂相的形成，并且相对于中性DMPC双层膜的作用增强。在凝胶相DMPC囊泡中，天然多肽通过表面机制破坏双层，类似物的作用类似于在流体相观察到的效果。通过DPI检测双分子层顺序的实时变化，并分析双分子层双折射的变化作为与双分子层结合的多肽质量的函数。虽然随着结合浓度的增加，这三种多肽都降低了双层结构的有序性，但斑点蛋白1.1引起的双层结构变化最大。核磁共振数据表明，斑蛋白1.1主要结合在双层的表面区域，核磁共振和DPI结果都表明这种结合导致了双层有序性的下降。总体而言，结果表明，残基15上的Pro在斑点蛋白1.1的膜相互作用中起着核心作用，它诱导了膜顺序的显著变化，并影响了双分子层从多肽结合和插入引起的结构变化中恢复的能力。
The role of proline in the disruption of membrane bilayer structure upon antimicrobial peptide (AMP) binding was studied. Specifically, P-31 and H-2 solid-state NMR and dual polarization interferometry (DPI) were used to analyze the membrane interactions of three AMPs: maculatin 1.1 and two analogs in which Pro-15 is replaced by Gly and Ala. For NMR, deuterated dimyristoylphosphatidylcholine (d(54)-DMPC) and d(54)-DMPC/dimyristoylphosphatidylglycerol (DMPG) were used to mimic eukaryotic and prokaryotic membranes, respectively. In fluid-phase DMPC bilayer systems, the peptides interacted primarily with the bilayer surface, with the native peptide having the strongest interaction. In the mixed DMPC/DMPG bilayers, maculatin 1.1 induced DMPG phase separation, whereas the analogs promoted the formation of isotropic and lipid-enriched phases with an enhanced effect relative to the neutral DMPC bilayers. In gel-phase DMPC vesicles, the native peptide disrupted the bilayer via a surface mechanism, and the effect of the analogs was similar to that observed in the fluid phase. Real-time changes in bilayer order were examined via DPI, with changes in bilayer birefringence analyzed as a function of the peptide mass bound to the bilayer. Although all three peptides decreased the bilayer order as a function of bound concentration, maculatin 1.1 caused the largest change in bilayer structure. The NMR data indicate that maculatin 1.1 binds predominantly at the surface regions of the bilayer, and both NMR and DPI results indicate that this binding leads to a drop in bilayer order. Overall, the results demonstrate that the proline at residue 15 plays a central role in the membrane interaction of maculatin 1.1 by inducing a significant change in membrane order and affecting the ability of the bilayer to recover from structural changes induced by the binding and insertion of the peptide.