Andre Guillaume, Brasseur Robert, Dufrêne Yves F
Unité de Chimie des Interfaces, Université catholique de Louvain, Croix du Sud 2/18, 1348 Louvain-la-Neuve, Belgium.
J Mol Recognit. 2007 Nov-Dec;20(6):538-45. doi: 10.1002/jmr.837.
Despite the vast body of literature that has accumulated on tilted peptides in the past decade, direct information on the forces that drive their interaction with lipid membranes is lacking. Here, we attempted to use atomic force microscopy (AFM) to explore the interaction forces between the Simian immunodeficiency virus peptide and phase-separated supported bilayers composed of various lipids, i.e. dipalmitoylphosphatidylcholine, dioleoylphosphatidylcholine, dioleoylphosphatidic acid and dipalmitoylphosphatidylethanolamine. Histidine-tagged peptides were attached onto AFM tips terminated with nitrilotriacetate and tri(ethylene glycol) groups, an approach expected to ensure optimal exposure of the C-terminal hydrophobic domain. Force-distance curves recorded between peptide-tips and the different bilayer domains always showed a long-range repulsion upon approach and a lack of adhesion upon retraction, in marked contrast with the hydrophobic nature of the peptide. To explain this unexpected behaviour, we suggest a mechanism in which lipids are pulled out from the bilayer due to strong interactions with the peptide-tip, in agreement with the very low force needed to extract lipids from supported bilayers.
尽管在过去十年里积累了大量关于倾斜肽的文献，但缺乏关于驱动其与脂质膜相互作用的力的直接信息。在这里，我们试图使用原子力显微镜（AFM）来探索猿猴免疫缺陷病毒肽与由各种脂质组成的相分离支撑双层膜之间的相互作用力，这些脂质即二棕榈酰磷脂酰胆碱、二油酰磷脂酰胆碱、二油酰磷脂酸和二棕榈酰磷脂酰乙醇胺。带有组氨酸标签的肽被连接到以次氮基三乙酸和三（乙二醇）基团终止的AFM针尖上，这种方法有望确保C端疏水结构域的最佳暴露。在肽针尖与不同双层膜区域之间记录的力-距离曲线在接近时总是显示出长程排斥力，在回缩时缺乏粘附力，这与肽的疏水性质形成明显对比。为了解释这种意外行为，我们提出了一种机制，即由于与肽针尖的强烈相互作用，脂质从双层膜中被拉出，这与从支撑双层膜中提取脂质所需的极低力相一致。
