黑寡妇蜘蛛毒液中的α-拉托昆虫毒素在双层脂质膜中形成的离子通道内腔的几何结构。

The geometry of the ionic chànnel lumen formed by alpha-latroinsectotoxin from black widow spider venom in the bilayer lipid membranes.

作者信息

Shatursky Oleg Ya, Volkova Tatyana M, Himmelreich Nina H, Grishin Eugene V

机构信息

Department of Neurochemistry, Palladin Institute of Biochemistry, Leontovich Str, 9, 01601, Kiev, Ukraine.

出版信息

Biochim Biophys Acta. 2007 Nov;1768(11):2757-63. doi: 10.1016/j.bbamem.2007.07.004. Epub 2007 Jul 19.

DOI:10.1016/j.bbamem.2007.07.004

PMID:17764656

Abstract

The dependence of single channel conductance formed by alpha-latroinsectotoxin (alpha-LIT) from black widow spider venom in the planar phospholipid membrane on the hydrodynamic radii of different nonelectrolytes allowed to determine the geometry of alpha-LIT water lumen. It was found that the cis- and trans-entrances of alpha-LIT channel had the same effective radii of 0.55-0.58 nm. Relatively small conductance of alpha-LIT channel (23.5+3.7 pS) in a symmetrical membrane bathing solution of 100 mM KCl (pH 7.4) may result from the constriction inside the channel with apparent radius of 0.37 nm located 32.5% of channel length away from the cis-entrance.

摘要

黑寡妇蜘蛛毒液中的α-拉托昆虫毒素（α-LIT）在平面磷脂膜中形成的单通道电导对不同非电解质流体动力学半径的依赖性，使得能够确定α-LIT水腔的几何形状。研究发现，α-LIT通道的顺式和反式入口具有相同的有效半径，为0.55 - 0.58纳米。在100 mM KCl（pH 7.4）的对称膜浴溶液中，α-LIT通道相对较小的电导（23.5 + 3.7 pS）可能是由于通道内部存在收缩，其表观半径为0.37纳米，位于距离顺式入口32.5%通道长度处。