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The Properties of Ion Channels in Lipid Membranes Modified by the Aromatic Antibiotic Levorin А 2
Biophysics Pub Date : 2020-10-19 , DOI: 10.1134/S0006350920040235
T. P. Taghi-zada , Kh. M. Kasumov

It has been shown that the main components of levorin A, that is, A0, A1, A2, or A3, that contain an aromatic group increase the permeability of membranes in the series A3 > A2 > A1 > A0 when they are on the same side of the membrane. All levorin components have cationic selectivity. The most studied levorin, А2, promotes the almost ideal permeability of membranes to potassium ions. The membrane potential for a ten-fold change in the KCl concentration gradient is 56 ± 2 mV. It has been shown that the injection of the same concentration of levorin А2 into one side of the membrane and then, after achieving the typical membrane permeability, into the other side of the membrane generates a two-fold increase in the total membrane permeability. This means that independent levorin-induced conductive semi-pores are formed on each side of the membrane. It has been found that the injection of levorin А2 only into one side of the membrane enhances the membrane permeability to monosaccharides and other neutral molecules. The presence of levorin А2 in cholesterol-, ergosterol-, and stigmasterol-containing phospholipid membranes has been shown to lead to the single-channel conductivity of typical ion channels of 0.2–0.5 pS. The properties of these channels have been studied. The levorin channels exist in two states, open and closed. Most of the time, the channel remains in the open state in the KBr solution. In solutions of different salts of the same concentration, the conductivity value of the levorin channels is approximately the same (0.4–0.5 pS). An increase in the dimethyl sulfoxide concentration in aqueous solutions facilitates the transition of polyene antibiotic molecules from dispersed to monomolecular form. The molecules of polyene antibiotics in the associated form exhibit high membrane activity.

中文翻译:

在类脂膜离子通道由芳香族抗生素LevorinА修改的属性 2

已经显示,含有芳香族基团的左旋蛋白A的主要成分,即A 0,A 1,A 2或A 3,增加了膜的渗透性,顺序为A 3 > A 2 > A 1 >甲0当它们在膜的同一侧。所有的levorin组分都具有阳离子选择性。研究最多的levorin,А 2,促进膜的钾离子的几乎理想的渗透性。KCl浓度梯度变化十倍的膜电位为56±2 mV。它已经显示出的levorinА相同浓度的注入2进入膜的一侧,然后在达到典型的膜渗透性之后,进入膜的另一侧,使总膜渗透性增加两倍。这意味着在膜的每一侧上形成了独立的由levorin诱导的导电半孔。已经发现,仅将levorin 2注射到膜的一侧可增强膜对单糖和其他中性分子的渗透性。的levorinА存在2含胆固醇,麦角固醇和豆甾醇的磷脂膜中的蛋白质显示出典型离子通道的单通道电导率为0.2–0.5 pS。已经研究了这些通道的特性。levorin通道以打开和关闭两种状态存在。大多数情况下,KBr解决方案中的通道保持打开状态。在相同浓度的不同盐溶液中,左旋蛋白通道的电导率值大致相同(0.4-0.5 pS)。水溶液中二甲基亚砜浓度的增加促进了多烯抗生素分子从分散形式转变为单分子形式。相关形式的多烯抗生素分子具有很高的膜活性。
更新日期:2020-10-19
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