Interactions between a pore-blocking peptide and the voltage sensor of the sodium channel: An electrostatic approach to channel geometry
Interactions between a pore-blocking peptide and the voltage sensor of the sodium channel: An electrostatic approach to channel geometry
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DOI：
10.1016/s0896-6273(00)80058-6
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发表时间：
1996-02-01
期刊：
影响因子：
16.2
通讯作者：
Horn, R
中科院分区：
文献类型：
--
作者：
French, RJ;PrusakSochaczewski, E;Horn, R
很少有实验数据阐明通过电压依赖性离子通道介导离子传导的分子结构与负责传感跨膜电压和控制门控的结构之间的关系。为了填补这一空白，我们使用了强阳离子、突变的 mu-芋螺毒素肽，它仅部分阻断通过电压依赖性钠通道的电流，以研究结合和非结合通道中的电压依赖性激活门控。当肽与离子传导孔结合时，它会抑制通道开放，从而需要更强的去极化来激活通道。我们表明，这种激活偏移可能完全是由电压感应 S4 电荷运动的静电抑制引起的，并估计了 S4 电荷移动的大致物理距离。
Few experimental data illuminate the relationship between the molecular structures that mediate ion conduction through voltage-dependent ion channels and the structures responsible for sensing transmembrane voltage and controlling gating. To fill this void, we have used a strongly cationic, mutated mu-conotoxin peptide, which only partially blocks current through voltage-dependent sodium channels, to study voltage-dependent activation gating in both bound and unbound channels. When the peptide binds to the ion-conducting pore, it inhibits channel opening, necessitating stronger depolarization for channel activation. We show that this activation shift could result entirely from electrostatic inhibition of the movement of the voltage-sensing S4 charges and estimate the approximate physical distance through which the S4 charges move.