GATING CURRENT NOISE PRODUCED BY ELEMENTARY TRANSITIONS IN SHAKER POTASSIUM CHANNELS
GATING CURRENT NOISE PRODUCED BY ELEMENTARY TRANSITIONS IN SHAKER POTASSIUM CHANNELS
复制标题
DOI：
10.1126/science.8160016
复制
发表时间：
1994-04-22
期刊：
影响因子：
56.9
通讯作者：
BEZANILLA, F
中科院分区：
文献类型：
--
作者：
SIGG, D;STEFANI, E;BEZANILLA, F
门控电流提供了电压敏感离子通道蛋白质内发生的电荷空间重排的直接记录。如果基元电荷作为非常短的离散电流脉冲运动，它们将在宏观选通电流中产生波动。用足够高的记录带宽测量了非洲爪哇卵母细胞表达的Shaker钾通道门控电流的变化，以估计基本跃迁电荷运动的幅度和时间分布。通道激活分两个连续阶段进行。第一阶段由许多快速跃迁组成，每个跃迁移动的少量电荷对门控电流的波动贡献很小，而第二阶段，贡献了大部分波动，由一些离散的、相关的跃迁表示，其中一个或多个跃迁携带至少2.4个基元电荷穿过膜场。
Gating currents provide a direct record of the spatial rearrangement of charges occurring within the protein of voltage-sensitive ion channels. If the elementary charges move as very brief discrete pulses of current, they will produce fluctuations in the macroscopic gating current. The variance of such fluctuations in gating currents was measured in Shaker potassium channels expressed in Xenopus oocytes with a sufficiently high recording bandwidth to estimate the magnitude and time distribution of the elementary transition charge movements. Channel activation occurred in two sequential stages. The first stage consisted of numerous, fast transitions, each moving small amounts of charge that contributed little to the fluctuation in gating current, whereas the second stage, which contributed the bulk of the fluctuation, was represented by a number of discrete, correlated transitions, one or more of which carried a charge of at least 2.4 elementary charges across the membrane field.