Sani Marc-Antoine, Gagne Eve, Gehman John D, Whitwell Thomas C, Separovic Frances
School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, VIC, 3010, Australia,
Eur Biophys J. 2014 Sep;43(8-9):445-50. doi: 10.1007/s00249-014-0970-0. Epub 2014 Jun 7.
A dye-release method for investigating the effect of a competitive lipid environment on the activity of two membrane-disrupting antimicrobial peptides (AMP), maculatin 1.1 and aurein 1.2, is presented. The results support the general conclusion that AMP have greater affinity for negatively charged membranes, for example bacterial membranes, than for the neutral membrane surface found in eukaryotic cells, but only within a competitive lipid environment. Indeed, in a single-model membrane environment, both peptides were more potent against neutral vesicles than against charged vesicles. The approach was also used to investigate the effect of pre-incubating the peptides in a neutral lipid environment then introducing charged lipid vesicles. Maculatin was shown to migrate from the neutral lipid bilayers, where pores had already formed, to the charged membrane bilayers. This result was also observed for charged-to-charged bilayers but, interestingly, not for neutral-to-neutral lipid interfaces. Aurein was able to migrate from either lipid environment, indicating weaker binding to lipid membranes, and a different molecular mechanism for lysis of lipid bilayers. Competitive lipid environments could be used to assess other critical conditions that modulate the activity of membrane peptides or proteins.
本文介绍了一种染料释放法，用于研究竞争性脂质环境对两种膜破坏抗菌肽（AMP）——maculatin 1.1和aurein 1.2活性的影响。结果支持了一个普遍结论，即AMP对带负电荷的膜（如细菌膜）的亲和力比对真核细胞中发现的中性膜表面的亲和力更大，但这仅在竞争性脂质环境中成立。实际上，在单模型膜环境中，两种肽对中性囊泡的作用比对带电荷囊泡的作用更强。该方法还用于研究在中性脂质环境中预孵育肽然后引入带电荷脂质囊泡的效果。结果表明，maculatin会从已经形成孔的中性脂质双层迁移到带电荷的膜双层。在带电荷到带电荷的双层中也观察到了这一结果，但有趣的是，在中性到中性脂质界面中未观察到。Aurein能够从任何一种脂质环境中迁移，这表明其与脂质膜的结合较弱，并且具有不同的脂质双层裂解分子机制。竞争性脂质环境可用于评估调节膜肽或蛋白质活性的其他关键条件。
