IONIC SELECTIVITY OF PORES FORMED BY THE MATRIX PROTEIN (PORIN) OF ESCHERICHIA-COLI
IONIC SELECTIVITY OF PORES FORMED BY THE MATRIX PROTEIN (PORIN) OF ESCHERICHIA-COLI
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DOI：
10.1016/0005-2736(89)90002-3
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发表时间：
1979-01-01
期刊：
影响因子：
--
通讯作者：
LAUGER, P
中科院分区：
文献类型：
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作者：
BENZ, R;JANKO, K;LAUGER, P
大肠杆菌外膜的基质蛋白（孔蛋白）与黑色脂质膜结合，形成单孔电导率为2ns （1m KCl）的离子渗透孔。通过测定不同电荷和大小的各种离子的选择性，获得了该孔的结构信息。通过对大有机离子（Tris+，葡萄糖胺+，Hepes-[2-[-4-（2-羟乙基）-1-胡椒锌基]-乙磺酸]）的孔渗透性估计，最小孔径为0.8 nm。在中性pH下，孔对碱离子的渗透性是氯离子的2-4倍。根据观察到的pH对渗透率的依赖性，这种阳离子选择性可以通过假设孔隙含有固定的负电荷来解释。
Incorporation of the matrix protein (porin) from the outer membrane of E. coli into black lipid films results in the formation of ion-permeable pores with a single-pore conductance of 2 nS (in 1 M KCl). Information on the structure of this pore was obtained by determining the selectivity of various ion species differing in charge and size. From the permeability of the pore for large organic ions (Tris+, glucosamine+, Hepes- [2-[-4-(2-hydroxyethyl)-1-piperra zinyl]-ethanesulfonic acid]) a minimum pore diameter of 0.8 nm is estimated. At neutral pH the pore is 2-4 times more permeable for alkali ions than for chloride. Based on the observed pH dependence of permeability, this cationic selectivity is explained by the assumption that the pore contains fixed negative charges.