Bezanilla F, Perozo E, Papazian D M, Stefani E
Department of Physiology, UCLA School of Medicine 90024.
Science. 1991 Nov 1;254(5032):679-83. doi: 10.1126/science.1948047.
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.
电压依赖性离子通道通过通道蛋白固有的带电电压传感器对膜电位变化做出反应。跨膜电位的变化导致这些带电残基移动，从而引起通道构象变化。带电传感器的移动可作为门控电流被检测到。对果蝇振子钾通道门控电流的测量表明，通道电压传感器上的电荷会因长时间去极化而逐渐固定。在缺乏失活功能的通道突变体中，电荷不会固定。这些结果表明，分子中负责失活的区域直接或间接与电压传感器相互作用，以防止电荷回到其原始位置。通道关闭状态之间的门控转变似乎并非相互独立，这表明通道亚基在激活过程中相互作用。
