MOLECULAR-BASIS OF GATING CHARGE IMMOBILIZATION IN SHAKER POTASSIUM CHANNELS
MOLECULAR-BASIS OF GATING CHARGE IMMOBILIZATION IN SHAKER POTASSIUM CHANNELS
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DOI：
10.1126/science.1948047
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发表时间：
1991-11-01
期刊：
影响因子：
56.9
通讯作者：
STEFANI, E
中科院分区：
文献类型：
--
作者：
BEZANILLA, F;PEROZO, E;STEFANI, E
电压依赖的离子通道通过通道蛋白固有的带电电压传感器对膜电位的变化做出反应。跨膜电位的变化导致这些带电残基的运动，从而导致通道的构象变化。带电传感器的运动可以被检测为被称为门控电流的电流。对果蝇振荡钾通道门控电流的测量表明，通道电压传感器上的电荷通过长时间的去极化而逐渐固定。这种电荷不会固定在缺乏失活的通道突变体中。这些结果表明，负责失活的分子区域直接或间接地与电压传感器相互作用，以防止电荷返回到其原始位置。通道关闭状态之间的门控转换似乎不是独立的，这表明通道亚单位在激活过程中相互作用。
Voltage-dependent ion channels respond to changes in the membrane potential by means of charged voltage sensors intrinsic to the channel protein. Changes in transmembrane potential cause movement of these charged residues, which results in conformational changes in the channel. Movements of the charged sensors can be detected as currents known as gating currents. Measurement of the gating currents of the Drosophila Shaker potassium channel indicates that the charge on the voltage sensor of the channels is progressively immobilized by prolonged depolarizations. The charge is not immobilized in a mutant of the channel that lacks inactivation. These results show that the region of the molecule responsible for inactivation interacts, directly or indirectly, with the voltage sensor to prevent the return of the charge to its original position. The gating transitions between closed states of the channel appear not to be independent, suggesting that the channel subunits interact during activation.