Use-dependent blockers and exit rate of the last ion from the multi-ion pore of a K+ channel

被引:197
作者
Baukrowitz, T [1 ]
Yellen, G [1 ]
机构
[1] HARVARD UNIV,SCH MED,DEPT NEUROBIOL,BOSTON,MA 02114
关键词
D O I
10.1126/science.271.5249.653
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
Quaternary ammonium blockers inhibit many voltage-activated potassium (K+) channels from the intracellular side. When applied to Drosophila Shaker potassium channels expressed in mammalian cells, these rapidly reversible blockers produced use-dependent inhibition through an unusual mechanism-they promoted an intrinsic conformational change known as C-type inactivation, from which recovery is slow. The blockers did so by cutting off potassium ion flow to a site in the pore, which then emptied at a rate of 10(5) ions per second. This slow rate probably reflected the departure of the last ion from the multi-ion pore: Permeation of ions (at 10(7) per second) occurs rapidly because of ion-ion repulsion, but the last ion to leave would experience no such repulsion.
引用
收藏
页码:653 / 656
页数:4
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