通道电压传感器中的质子孔揭示了聚焦的电场
Dorine M Starace1, Francisco Bezanilla
1Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, California 90095, USA.
Nature
|February 7, 2004
概括
电压通道通过带电段控制神经冲动. 产生质子孔的突变挑战了质子孔的作用.
科学领域:
- 神经科学是一个神经科学.
- 生物物理学的生物物理.
- 结构生物学 结构生物学
背景情况:
- 电压依赖的通道对于产生神经冲动至关重要.
- 电压敏感性源于S4跨膜段中的充电残留物.
- "电压传感器"模型建议在通道激活过程中S4螺旋运动.
研究的目的:
- 为了研究通道中电压传感的机制.
- 为了测试"电压传感器"模型的有效性.
- 探索特定充电残留物在通道封闭中的作用.
主要方法:
- 谢克通道的局部导向突变发生 (用histidine取代S4阿尔金因).
- 电生理学记录以评估离子和质子流量.
- 在超极化条件下分析通道行为.
主要成果:
- 一个特定的突变 (R到H) 在超极化电位上创造了质子孔.
- 这种质子孔形成与"电压传感器"模型不一致.
- 有证据表明,一个狭窄的蛋白质屏障将电场集中在电压敏感区域.
结论:
- 这些发现不支持"电压传感器"模型.
- 建议在超极化潜力下进行局部电场效应.
- 这种机制涉及一个狭窄的屏障,在道蛋白内分离水溶液.
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