Tang Ya-Li, Shi Yong-Hui, Zhao Wei, Hao Gang, Le Guo-Wei
State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, People's Republic of China.
J Pharm Biomed Anal. 2008 Dec 1;48(4):1187-94. doi: 10.1016/j.jpba.2008.09.006. Epub 2008 Sep 10.
Antimicrobial molecules from insects may serve as a potentially significant group of antibiotics. To identify the effect of antimicrobial peptides (AMPs) on bacterial membrane and obtain further insight in the mechanism of membrane transport of AMPs, the interaction of surface potential and permeation of a novel antimicrobial peptide MDpep5 (Val-Glu-Ser-Trp-Val) from Chinese traditional edible larvae of housefly was examined using liposomes from bacterial lipids extract. Compared with the cationic AMPs, MDpep5 cannot completely disrupt membrane. The uptake of MDpep5 by bacterial liposomes was dependent on the membrane surface potential. The mutual inhibition of the transport of MDpep5 through the cell membrane was caused by the change in surface potential due to the binding of MDpep5 to the membrane. Furthermore, formation of MDpep5-enriched lipid aggregates could lead to the disorder of the bilayer structure. Based on our experimental data, we propose that MDpep5 initiated its antimicrobial activity by profoundly disordering the structure and affecting physical properties of bacterial membrane when binding to the phospholipid which accounts for its bactericidal activity.
昆虫产生的抗菌分子可能是一类具有潜在重要意义的抗生素。为了确定抗菌肽（AMPs）对细菌膜的作用，并进一步深入了解AMPs的膜转运机制，我们使用从细菌脂质提取物中制备的脂质体，研究了一种来自中国传统食用家蝇幼虫的新型抗菌肽MDpep5（Val-Glu-Ser-Trp-Val）的表面电位与渗透之间的相互作用。与阳离子AMPs相比，MDpep5不能完全破坏膜。细菌脂质体对MDpep5的摄取取决于膜表面电位。MDpep5与膜结合导致表面电位变化，从而引起其通过细胞膜转运的相互抑制。此外，富含MDpep5的脂质聚集体的形成可能导致双层结构紊乱。基于我们的实验数据，我们提出MDpep5在与磷脂结合时，通过深刻扰乱细菌膜的结构并影响其物理性质来启动抗菌活性，这解释了其杀菌活性。
