Walsh Olivia D, Choi Leona, Sigdel Krishna P
Department of Physics and Astronomy, California State Polytechnic University, Pomona, CA 91768, USA.
Membranes (Basel). 2023 Oct 28;13(11):864. doi: 10.3390/membranes13110864.
Antimicrobial peptides are key components of the immune system. These peptides affect the membrane in various ways; some form nano-sized pores, while others only produce minor defects. Since these peptides are increasingly important in developing antimicrobial drugs, understanding the mechanism of their interactions with lipid bilayers is critical. Here, using atomic force microscopy (AFM), we investigated the effect of a synthetic hybrid peptide, CM15, on the membrane surface comprising polar lipid extract. Direct imaging of supported lipid bilayers exposed to various concentrations of the peptide revealed significant membrane remodeling. We found that CM15 interacts with supported lipid bilayers and forms membrane-spanning defects very quickly. It is found that CM15 is capable of remodeling both leaflets of the bilayer. For lower CM15 concentrations, punctate void-like defects were observed, some of which re-sealed themselves as a function of time. However, for CM15 concentrations higher than 5 µM, the defects on the bilayers became so widespread that they disrupted the membrane integrity completely. This work enhances the understanding of CM15 interactions with the bacterial lipid bilayer.
抗菌肽是免疫系统的关键组成部分。这些肽以多种方式作用于细胞膜；有些形成纳米级的孔，而另一些只产生微小的缺陷。由于这些肽在开发抗菌药物方面越来越重要，了解它们与脂质双层相互作用的机制至关重要。在此，我们使用原子力显微镜（AFM）研究了一种合成杂合肽CM15对包含极性脂质提取物的膜表面的影响。对暴露于不同浓度肽的支持脂质双层进行直接成像，揭示了显著的膜重塑。我们发现CM15与支持脂质双层相互作用并非常迅速地形成跨膜缺陷。研究发现CM15能够重塑双层的两个小叶。对于较低的CM15浓度，观察到点状空洞样缺陷，其中一些随着时间的推移自行重新封闭。然而，对于高于5μM的CM15浓度，双层上的缺陷变得非常普遍，以至于完全破坏了膜的完整性。这项工作增进了对CM15与细菌脂质双层相互作用的理解。
