Department of Physics, University of Los Andes, Carrera 1 N° 18A - 12, Bogotá, Colombia.
CNR-Nanoscience Institute-S3, Via Campi 213/A, 41125 Modena, Italy.
Biochim Biophys Acta Biomembr. 2018 Dec;1860(12):2635-2643. doi: 10.1016/j.bbamem.2018.10.003. Epub 2018 Oct 4.
Given the increasing trend in bacterial antibiotic resistance, research on antimicrobial peptides and their mechanisms of action has become of huge relevance in the last years. Several studies have investigated the effects of a large variety of antimicrobial peptides directly on bacteria or on model lipid bilayers. In the case of model lipid bilayers, different systems are typically exploited; however, different results could be obtained due to the specific properties of the used system. Supported Lipid Bilayers and Giant Unilamellar Vesicles are among the most popular model systems. Here we used Atomic Force Microscopy and fluorescence microscopy to study the interaction of the antimicrobial peptide Magainin H2, an analog of Magainin 2 with increased hydrophobicity, on Supported Lipid Bilayers. We found that, for this kind of model bilayer, due to its strong interaction with the support, the lateral expansion of the membrane induced by the interaction with the peptides is initially inhibited and subsequently proceeds creating new bilayer regions with many defects. This scenario gives rise in Supported Lipid Bilayers to effects like initial increase of lateral pressure, formation of lipid tubes to release this increase, or development of bilayer regions with lower lipid density. Our results highlight that care should be given to the selected model system when studying and comparing the interaction of peptides with other lipid bilayer model systems.
鉴于细菌对抗生素的耐药性呈上升趋势，近年来，对抗微生物肽及其作用机制的研究变得非常重要。许多研究直接在细菌或模型脂质双层上研究了各种抗菌肽的作用。在模型脂质双层的情况下，通常会利用不同的系统；然而，由于所用系统的特定性质，可能会得到不同的结果。支持的脂质双层和巨大的单分子层囊泡是最受欢迎的模型系统之一。在这里，我们使用原子力显微镜和荧光显微镜研究了抗菌肽 Magainin H2（Magainin 2 的类似物，疏水性增加）在支持的脂质双层上的相互作用。我们发现，对于这种模型双层，由于其与支撑物的强烈相互作用，与肽相互作用引起的膜的横向扩展最初受到抑制，随后进行，在许多缺陷处创建具有许多缺陷的新双层区域。这种情况在支持的脂质双层中会产生一些效果，例如侧向压力的初始增加、形成脂质管以释放这种增加，或者形成具有较低脂质密度的双层区域。我们的研究结果表明，在研究和比较肽与其他脂质双层模型系统的相互作用时，应注意所选的模型系统。
