Antibacterial peptide pleurocidin forms ion channels in planar lipid bilayers.
Antibacterial peptide pleurocidin forms ion channels in planar lipid bilayers.
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DOI：
10.1016/s0005-2736(02)00470-4
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发表时间：
2002-08
期刊：
影响因子：
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通讯作者：
N. Saint;H. Cadiou;Yannick Bessin;G. Molle
中科院分区：
文献类型：
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作者：
N. Saint;H. Cadiou;Yannick Bessin;G. Molle
Pleurocidin是从比目鱼皮肤分泌物中分离得到的一种25个氨基酸残基的α螺旋阳离子肽，具有很强的抗菌活性，并在宿主的天然防御中发挥作用。该肽将负责细菌膜中的孔形成，导致裂解并因此死亡。在这项研究中，我们研究了pleurocidin在不同的平面脂质双层的行为，以确定其膜透化的机制。宏观电导实验表明，pleurocidin没有显示中性磷脂酰胆碱/磷脂酰乙醇胺（PC/PE）脂质双层的成孔活性。然而，在7：3：1 PC/PE/磷脂酰丝氨酸（PS）脂质双层，pleurocidin显示在不同的肽浓度的可重复的I/V曲线。该活性通过单通道实验证实，因为如果脂质混合物含有阴离子脂质（PS），则获得了定义明确的离子通道。离子通道的特性，如-没有电压依赖性，只有一个单一的电导，线性关系船舶电流-电压-，是不赞成的膜透化根据桶模型，而是由环形孔的形成。
Pleurocidin, a 25-residue α helical cationic peptide, isolated from skin mucous secretions of the winter flounder, displays a strong anti-microbial activity and appears to play a role in innate host defence. This peptide would be responsible for pore formation in the membrane of bacteria leading to lysis and therefore death. In this study, we investigated the behaviour of pleurocidin in different planar lipid bilayers to determine its mechanism of membrane permeabilisation. Macroscopic conductance experiments showed that pleurocidin did not display a pore-forming activity in neutral phosphatidylcholine/phosphatidylethanolamine (PC/PE) lipid bilayers. However, in 7:3:1 PC/PE/phosphatidylserine (PS) lipid bilayers, pleurocidin showed reproducible I/V curves at different peptide concentrations. This activity is confirmed by single-channel experiments since well-defined ion channels were obtained if the lipid mixture was containing an anionic lipid (PS). The ion channel characteristics such as—no voltage dependence, only one unitary conductance, linear relation ship current–voltage—, are not in favour of the membrane permeabilisation according to the barrel model but rather by the toroidal pore formation.