Tanifuji M, Sokabe M, Kasai M
Department of Biophysical Engineering, Faculty of Engineering Science, Osaka University, Japan.
J Membr Biol. 1987;99(2):103-11. doi: 10.1007/BF01871230.
An anion channel of sarcoplasmic reticulum vesicle has been incorporated into planar lipid bilayers by means of a fusion method and its basic properties were investigated. Analysis of fusion processes suggested that one SR vesicle contained approximately one anion channel. The conductance of this channel has several substates and shows a flickering behavior. The occupation probability of each substate was voltage dependent, which induced an inward rectification of macroscopic currents. Further, the anion channel was found to have the following properties. (1) The single-channel conductance is about 200 pS at 100 mM Cl-. (2) The channel does not select among monovalent anions but SO2-4 hardly permeates through the channel. (3) SO2-4 added to the cis side (the side to which SR vesicles were added) inhibits Cl- current competitively in a voltage-dependent manner. (4) An analysis of this voltage dependence suggests that the binding site of SO2-4 is located at about 36% of the way across the channel from the cis entrance.
通过融合方法将肌浆网囊泡的阴离子通道整合到平面脂质双分子层中，并对其基本特性进行了研究。融合过程分析表明，一个肌浆网囊泡大约包含一个阴离子通道。该通道的电导有几个亚态，并表现出闪烁行为。每个亚态的占据概率取决于电压，这导致宏观电流的内向整流。此外，发现该阴离子通道具有以下特性。(1) 在100 mM Cl- 时，单通道电导约为200 pS。(2) 该通道对单价阴离子不具有选择性，但SO2-4 几乎不能透过该通道。(3) 添加到顺式侧（添加肌浆网囊泡的一侧）的SO2-4 以电压依赖性方式竞争性抑制Cl- 电流。(4) 对这种电压依赖性的分析表明，SO2-4 的结合位点位于从顺式入口到通道全长约36% 的位置。
