Investigation of toroidal pore and oligomerization by melittin using transmission electron microscopy
Investigation of toroidal pore and oligomerization by melittin using transmission electron microscopy
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DOI：
10.1016/j.bbrc.2006.02.090
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发表时间：
2006-04-28
影响因子：
3.1
通讯作者：
Hahm, KS
中科院分区：
文献类型：
--
作者：
Park, SC;Kim, JY;Hahm, KS
我们研究了蜂毒素对各种细胞壁成分和不同脂肪成分的囊泡的影响。为了与细胞膜相互作用，蜂毒素必须穿过由低聚糖组成的细胞壁。在这里，我们发现蜂毒素对甲壳素、肽聚糖和脂多糖有很强的亲和力。我们进一步考察了脂类成分对蜂毒素裂解膜的影响。结果表明，蜂毒素对负电荷的结合能力强于对两性离子脂泡的结合，但对两性离子脂泡的渗漏作用更强。我们的研究进一步表明，在环状孔道的形成过程中，蜂毒素的低聚状态在四聚体和八聚体之间存在差异。葡聚糖渗漏实验证实了这些环状孔的形成和尺寸。最后，透射电子显微镜显示蜂毒素是通过环状成孔机制通过多肽齐聚形成孔道的。环状小孔由7~8 nm直径的环组成，环绕着两性离子脂泡上3.5~4.5 nm直径的空腔。(C)2006 Elsevier Inc.保留所有权利。
We studied the effects of melittin on various cell wall components and vesicles of various lipid compositions. To interact with the cytoplasmic membrane, melittin must traverse the cell wall, which is composed of oligosaccharides. Here, we found that melittin had a strong affinity for chitin, peptidoglycan, and lipopolysaccharide. We further examined the influence of lipid compositions on the lysis of the membranes by melittin. The result showed that melittin bound better to negatively charged than to zwitterionic lipid vesicles but was more potent at inducing leakage from zwitterionic lipid vesicles. Our studies further indicated that the oligomeric state of melittin varied between tetramers and octamers during the formation of toroidal pores. Dextran leakage experiments confirmed the formation and dimension of these toroidal pores. Finally, transmission electron microscopy revealed that melittin formed pores via peptide oligomerization by the toroidal pore-forming mechanism. The toroidal pores composed of 7-8 nm diameter rings that encircled 3.5-4.5 nm diameter cavities on zwitterionic lipid vesicles. (c) 2006 Elsevier Inc. All rights reserved.