Matsuzaki K, Murase O, Miyajima K
Faculty of Pharmaceutical Sciences, Kyoto University, Japan.
Biochemistry. 1995 Oct 3;34(39):12553-9. doi: 10.1021/bi00039a009.
The kinetics of the pore formation by magainin 2, an antimicrobial peptide from Xenopus laevis, in lipid vesicles was investigated. The pore formation was estimated by the efflux of a fluorescent dye, calcein, from large unilamellar vesicles composed of egg yolk phosphatidylglycerol. The time courses of the dye release were well-described by a novel model in which the peptide molecules translocate from the outer to the inner monolayer by forming a pore. The concentration dependence of the leakage rate suggested that the pore consists of pentameric magainin. The obtained kinetic parameters estimate that, at a lipid-to-peptide molar ratio of 117, 9 pores with a lifetime of 40 microseconds open per second per vesicle in the initial phase. The apparent deactivation of the pore with increasing time can be ascribed to the reduced peptide density in the outer leaflet due to the translocation. Incorporation of phosphatidylcholine destabilized the pore, indicating the importance of anionic lipids in the stable pore formation.
对非洲爪蟾抗菌肽马盖宁2在脂质囊泡中形成孔道的动力学进行了研究。通过荧光染料钙黄绿素从由蛋黄磷脂酰甘油组成的大单层囊泡中的流出量来估算孔道的形成。染料释放的时间进程可以用一个新模型很好地描述，在该模型中，肽分子通过形成孔道从外单层转运到内单层。泄漏速率的浓度依赖性表明孔道由五聚体马盖宁组成。获得的动力学参数估计，在脂质与肽的摩尔比为117时，在初始阶段每个囊泡每秒有9个寿命为40微秒的孔道打开。随着时间的增加，孔道明显失活可归因于由于转运导致外小叶中肽密度降低。磷脂酰胆碱的掺入使孔道不稳定，表明阴离子脂质在稳定孔道形成中的重要性。
