VOLTAGE-DEPENDENT CESIUM BLOCKADE OF A CATION CHANNEL FROM FRAGMENTED SARCOPLASMIC-RETICULUM

被引：113

作者：

CORONADO, R ^{[1
]}

MILLER, C ^{[1
]}

机构：

[1] BRANDEIS UNIV, GRAD DEPT BIOCHEM, WALTHAM, MA 02154 USA

来源：

NATURE | 1979年 / 280卷 / 5725期

关键词：

D O I：

10.1038/280807a0

中图分类号：

O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];

学科分类号：

07 ; 0710 ; 09 ;

摘要：

Cs+ ions block the K+ conductance of a voltage-gated ionic channel derived from fragmented sarcoplasmic reticulum (SR) and incorporated into an artificial phospholipid bilayer. The block follows a single-site titration curve with a voltage-dependent dissociation constant of 18 mM at +50 mV. Blockade observed with the macroscopic conductance can be fully accounted for by the reduction of the apparent single-channel conductance in the presence of Cs+. The voltage dependence is explained by assuming that Cs+ binds to the open state of a single channel on a site located about 40% of the way through the membrane from the cis side (the side to which the SR vesicles are added). The blocking site is accessible only from the cis side. © 1979 Nature Publishing Group.

引用

页码：807 / 810

页数：4

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