Effect of osmotic pressure on pore formation in lipid bilayers by the antimicrobial peptide magainin 2
Effect of osmotic pressure on pore formation in lipid bilayers by the antimicrobial peptide magainin 2
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DOI：
10.1039/d1cp05764b
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发表时间：
2022-02-24
影响因子：
3.3
通讯作者：
Yamazaki, Masahito
中科院分区：
文献类型：
--
作者：
Billah, Md Masum;Saha, Samiron Kumar;Yamazaki, Masahito
渗透压(Pi)引起细胞和脂泡的膜张力，可能通过未知的机制影响抗菌肽(AMPs)的活性。我们最近对生理条件下pi引起的巨大单层囊泡(GUV)的膜张力进行了定量研究。在这里，我们应用这种方法来研究pi对AMP Mainin 2(MAG)与单个GUVS相互作用的影响。在低pi值下，MAG诱导形成纳米尺度的孔洞，水溶性荧光探针AF488通过这些孔洞穿透细胞膜。MAG诱导成孔的速率常数k(P)随pi的增大而增大。已有研究表明，MAG与外叶结合所引起的GUV内叶的膜张力(Sigma(In))在MAG诱导的孔道形成中起重要作用。在pi下MAG和GUV之间的相互作用中，由于pi，sigma(In)增加，从而增加了k(P)。由pi和Mag引起的k(P)与总西格玛(In)之间的关系与没有pi时的关系一致。相反，MAG在较高的pi下导致GUV子集的断裂。利用带高速摄像机的荧光显微镜，揭示了GUV断裂过程。首先，在单个GUVS中观察到一个微米级的小孔隙。然后，在不改变GUV直径的情况下，孔半径在接近100ms的范围内增大，同时孔缘处的膜厚度增加，最终GUV转变为膜聚集体。在这些结果的基础上，我们讨论了pi在MAG诱导的GUV膜损伤中的作用。
Osmotic pressure (pi) induces membrane tension in cells and lipid vesicles, which may affect the activity of antimicrobial peptides (AMPs) by an unknown mechanism. We recently quantitated the membrane tension of giant unilamellar vesicles (GUVs) due to pi under physiological conditions. Here, we applied this method to examine the effect of pi on the interaction of the AMP magainin 2 (Mag) with single GUVs. Under low pi values, Mag induced the formation of nanometer-scale pores, through which water-soluble fluorescent probe AF488 permeates across the membrane. The rate constant for Mag-induced pore formation (k(p)) increased with increasing pi. It has been proposed that the membrane tension in the GUV inner leaflet (sigma(in)) caused by Mag binding to the outer leaflet plays a vital role in Mag-induced pore formation. During the interactions between Mag and GUVs under pi, the sigma(in) increases due to pi, thereby increasing k(p). The relationship between the k(p) and the total sigma(in) due to pi and Mag agreed with that without pi. In contrast, Mag induced rupture of a subset of GUVs under higher pi. Using fluorescence microscopy with a high-speed camera, the GUV rupture process was revealed. First, a small micrometer-scale pore was observed in individual GUVs. Then, the pore radius increased within similar to 100 ms without changing the GUV diameter and concomitantly the thickness of the membrane at the pore rim increased, and finally the GUV transformed into a membrane aggregate. Based on these results, we discussed the effect of pi on Mag-induced damage of GUV membranes.