Divalent cations modulate membrane binding and pore formation of a potent antibiotic peptide analog of alamethicin
Divalent cations modulate membrane binding and pore formation of a potent antibiotic peptide analog of alamethicin
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DOI：
10.1016/j.ceca.2012.11.012
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发表时间：
2013-03-01
期刊：
影响因子：
4
通讯作者：
Rispoli, Giorgio
中科院分区：
文献类型：
--
作者：
Aquila, Marco;Benedusi, Mascia;Rispoli, Giorgio
对一种强效抗生素肽——丙甲菌素F50/5的合成类似物（[L - 谷氨酸（OMe）（7,18,19）]）的孔形成（和解聚）动力学的Ca2 +调节作用进行了原位和体外研究。原位实验包括对分离的视网膜视杆外段（OS）进行全细胞记录，因为一旦用饱和光阻断唯一的OS内源性电导，电流就会完全通过由该肽形成的（外源性）通道。在不同浓度的二价阳离子存在下，测量了在OS细胞外侧施加和去除肽（约50毫秒）所引起的电流变化动力学。体外实验包括利用表面等离子体共振光谱（SPR）研究二价阳离子对[L - 谷氨酸（OMe）（7,18,19）]与固定在传感器芯片表面的模拟OS膜结合的调节作用。即使是低毫摩尔浓度的Ca2 +或Mg2 +的存在，也足以使[L - 谷氨酸（OMe）（7,18,19）]对模拟OS膜的表观亲和力提高约4倍，这使得在OS中该肽诱导的电流的激活相对于低Ca2 +加快了约10倍。原位和体外实验表明，高浓度的二价阳离子也增加了膜的刚性，这与它们对提高孔形成速率的作用相反。（C）2012爱思唯尔有限公司。保留所有权利。
The Ca2+ modulation of pore formation (and disaggregation) kinetics of a synthetic analog of alamethicin F50/5 ([L-Glu(OMe)(7,18,19)]), a potent antibiotic peptide, was investigated in situ and in vitro. The in situ experiments consisted in whole-cell recording from isolated retinal rod outer segments (OS), because once blocking the only OS endogenous conductance with saturating light, the current flows entirely through the (exogenous) channels formed by the peptide. The kinetics of current change induced by peptide application and removal (in similar to 50 ms) on the OS extracellular side was measured in the presence of divalent cations at different concentrations. The in vitro experiments consisted on the divalent cations modulation of [L-Glu(OMe)(7,18,19)] binding to a mimetic OS membrane immobilized on a sensor chip surface, employing surface plasmon resonance spectroscopy (SPR). The presence of even low mM Ca2+ or Mg2+ sufficed to increase the [L-Glu(OMe)(7,18,19)] apparent affinity for the mimetic OS membrane up to similar to 4-fold, which accelerated the activation of the peptide-induced current in OS by similar to 10-fold with respect to low Ca2+. In situ and in vitro experiments indicate that high concentrations of divalent cations increased also membrane rigidity, contrasting their effect on increasing the pore formation rate. (C) 2012 Elsevier Ltd. All rights reserved.