Interaction of melittin with solid supported membranes
Interaction of melittin with solid supported membranes
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DOI：
10.1039/b003865m
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发表时间：
2000-01-01
影响因子：
3.3
通讯作者：
Janshoff, A
中科院分区：
文献类型：
--
作者：
Steinem, C;Galla, HJ;Janshoff, A
膜活性肽蜂毒肽与固体支持的脂质双层的相互作用已被审查通过阻抗谱和扫描力显微镜。高柔性的脂质双分子层锚定通过亲水性间隔终止的硫醇基团上的金被用来调查蜂毒肽的影响，通过交流阻抗分析的电参数的膜。观察到蜂毒肽诱导的膜的电容和电导率的增加，表明蜂毒肽诱导这些固定化脂质双层内的缺陷。在不存在和存在EDTA的情况下进行实验，以研究蜂毒肽样品中剩余磷脂酶A（2）的影响以及来自意大利蜜蜂的磷脂酶A（2）的唯一影响。结果表明，蜂毒肽对双分子膜的电参数的影响最明显时，发现EDTA不存在，揭示磷脂酶A（2）和蜂毒肽的协同效应。用TappingMode扫描力显微镜观察了蜂毒素和磷脂酶A（2）联合作用下固体支撑膜的形态变化。在加入蜂毒肽后几分钟内观察到脂质层的溶解和非层状、盘状结构的形成，支持肽作用的“地毯样”机制，留下混合的肽脂质胶束。扫描力显微镜使我们能够在一次扫描中解决蜂毒肽的渐进作用。
The interaction of the membrane active peptide melittin with solid supported lipid bilayers has been scrutinized by means of impedance spectroscopy and scanning force microscopy. Highly flexible lipid bilayers anchored via a hydrophilic spacer terminated by a thiol group onto gold were used to investigate the influence of melittin on the electrical parameters of membranes by means of ac impedance analysis. A melittin induced increase in the capacitance and conductivity of the membrane was observed suggesting that melittin induces defects within these immobilized lipid bilayers. Experiments were performed in the absence and presence of EDTA to investigate the influence of remaining phospholipase A(2) in the melittin sample as well as the sole impact of phospholipase A(2) from Apis mellifera. It was shown that the most pronounced influence of melittin on the electrical parameters of bilayers was found when EDTA was absent, revealing a synergistic effect of phospholipase A(2) and melittin. Morphological changes of solid supported membranes induced by the combined effect of melittin and phospholipase A(2) were visualized by TappingMode scanning force microscopy in aqueous solution. Dissolution of the lipid layer and the formation of non-lamellar, discoid structures was observed within minutes after addition of melittin, supporting a "carpet-like'' mechanism of peptide action leaving mixed peptide lipid micelles behind. Scanning force microscopy allowed us to resolve the gradual action of melittin within one single scan.