Antimicrobial peptide magainin 2-induced rupture of single giant unilamellar vesicles comprising E. coli polar lipids
Antimicrobial peptide magainin 2-induced rupture of single giant unilamellar vesicles comprising E. coli polar lipids
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DOI：
10.1016/j.bbamem.2022.184112
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发表时间：
2023-01-06
影响因子：
3.4
通讯作者：
Yamazaki, Masahito
中科院分区：
文献类型：
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作者：
Billah, Md Masum;Rashid, Md Mamun Or;Yamazaki, Masahito
大多数抗菌肽（AMPs）破坏细菌细胞的细胞膜并诱导细胞内内容物快速渗漏，这是其杀菌活性的主要原因。其中一种AMPs， magainin 2 (Mag)，在含有磷脂酰胆碱（PC）和磷脂酰甘油（PG）的巨大单层囊泡（GUVs）中形成纳米孔，诱导荧光探针泄漏。在本研究中，为了阐明磁诱导大肠杆菌细胞膜脂质双层区域的孔形成，我们研究了磁与含有大肠杆菌极性脂质（E. coli- lipids - guv）的单一guv的相互作用。首先，我们研究了单个大肠杆菌脂质guv的荧光探针AF488的磁诱导渗漏，发现磁引起guv破裂，诱导AF488快速渗漏。磁致GUV破裂的速率常数随磁浓度的增加而增大。在时间分辨率为5 ms的荧光显微镜下，我们揭示了GUV破裂的过程：首先在GUV膜上观察到一个小的微孔，然后在不改变GUV直径的情况下，在50 ms内孔半径增加，孔边缘的膜厚度随之增加，最终形成膜聚集体。在GUV破裂前，磁仅与GUV的外单层结合，这增加了GUV双层的面积。我们还研究了大肠杆菌脂质- guv本身的物理性质。我们发现大肠杆菌脂质guvs的恒张力诱导破裂速率常数高于PG/PC-GUVs。在此基础上，我们讨论了磁诱导大肠杆菌脂质- guv破裂及其机制。
Most antimicrobial peptides (AMPs) damage the cell membrane of bacterial cells and induce rapid leakage of the internal cell contents, which is a main cause of their bactericidal activity. One of the AMPs, magainin 2 (Mag), forms nanopores in giant unilamellar vesicles (GUVs) comprising phosphatidylcholine (PC) and phosphatidylglycerol (PG), inducing leakage of fluorescent probes. In this study, to elucidate the Mag-induced pore formation in lipid bilayer region in E. coli cell membrane, we examined the interaction of Mag with single GUVs comprising E. coli polar lipids (E. coli-lipid-GUVs). First, we investigated the Mag-induced leakage of a fluorescent probe AF488 from single E. coli-lipid-GUVs, and found that Mag caused rupture of GUVs, inducing rapid AF488 leakage. The rate constant of Mag-induced GUV rupture increased with the Mag concentration. Using fluorescence microscopy with a time resolution of 5 ms, we revealed the GUV rupture process: first, a small micropore was observed in the GUV membrane, then the pore radius increased within 50 ms without changing the GUV diameter, the thickness of the membrane at the pore rim concomitantly increased, and eventually membrane aggregates were formed. Mag bound to only the outer monolayer of the GUV before GUV rupture, which increased the area of the GUV bilayer. We also examined the physical properties of E. coli-lipid-GUVs themselves. We found that the rate constant of the constant tension-induced rupture of E. coli-lipid-GUVs was higher than that of PG/PC-GUVs. Based on these results, we discussed the Mag-induced rupture of E. coli-lipid-GUVs and its mechanism.