Abstract

The role of various membrane components, phospholipids and lipopolysaccharides, in the formation and functioning of ion channels formed by lantibiotics of class A, nisin, and class B, cinnamycin and duramycin, was studied. Threshold concentrations of the tested lantibiotics were determined that cause ion channel formation and destruction of planar lipid bilayers. It was found that nisin was able to form ion channels with a conductance in the range from 2 to 600 pS at a concentration of more than 40 μM both in negatively charged lipid bilayers containing a specific adjuvant of gram-negative bacterial membranes, Kdo₂–lipid A, and in cardiolipin-containing membranes. The obtained results allowed suggesting that in model lipid membranes without lipid II, a precursor of peptidoglycan of gram-positive bacteria, which is a specific receptor of nisin, its role can be performed by Kdo₂–lipid A and cardiolipin. It was found that cinnamycin and its close analogue duramycin at concentrations of 1.5–3 μM induced step-like current fluctuations corresponding to the functioning of single ion channels with amplitudes from 5 to 30 pS and from 50 to 900 pS in membranes of phosphatidylethanolamine and cardiolipin-enriched bilayers, respectively. Based on the results obtained, we conclude that the channel-forming ability of cinnamycin and duramycin depends on the presence in the membrane of lipids prone to the formation of inverted hexagonal phases and the induction of spontaneous negative curvature in lipid monolayers.

中文翻译：

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羊毛硫抗生素的通道形成能力对膜脂质组成的依赖性

摘要

研究了各种膜成分、磷脂和脂多糖在 A 类羊毛硫抗生素、乳酸链球菌素和 B 类肉桂霉素和耐久霉素形成的离子通道的形成和功能中的作用。确定了导致离子通道形成和平面脂质双层破坏的受试羊毛硫抗生素的阈值浓度。发现乳酸链球菌肽能够以超过 40 μM 的浓度在含有革兰氏阴性细菌膜特定佐剂 Kdo _{2的带负电荷的脂质双层中形成电导范围为 2 至 600 pS 的离子通道}-脂质A，以及含心磷脂的膜。获得的结果表明，在没有脂质 II 的模型脂质膜中，革兰氏阳性细菌肽聚糖的前体，它是乳酸链球菌肽的特异性受体，其作用可以通过 Kdo _2来执行– 脂质 A 和心磷脂。发现浓度为 1.5-3 μM 的肉桂霉素及其密切类似物耐久霉素诱导阶梯状电流波动，对应于单个离子通道的功能，在磷脂酰乙醇胺和心磷脂膜中振幅为 5 至 30 pS 和 50 至 900 pS -富集的双层，分别。基于所获得的结果，我们得出结论，肉桂霉素和耐久霉素的通道形成能力取决于膜中脂质的存在，这些脂质易于形成倒六角相和脂质单层中自发负曲率的诱导。