截断的BK通道电压激活的原子模拟
1Department of Chemistry, University of Massachusetts, Amherst, MA 01003, USA.
bioRxiv : the preprint server for biology
|July 15, 2025
概括
长时间模拟显示了大 (BK) 通道中电压传感器领域的明显移动. 温和的S4螺旋运动,加上电场梯度,通过非正规路径驱动BK通道门.
科学领域:
- 生物物理学的生物物理.
- 分子生物学分子生物学
- 计算生物学 计算生物学
背景情况:
- 离子通道的电压依赖性封闭对于生理和病理生理过程至关重要.
- 电压门中的中断会导致通道病变.
- 大 (BK) 通道中的电压传感器域 (VSD) 运动与正规的KV通道不同,并且对其了解甚微.
研究的目的:
- 通过使用长时间尺度的原子学模拟,直接探测BK通道的电压诱导的门过渡.
- 分析BK VSD的激活状态并确定关键的机械特征.
- 阐明BK通道的独特封闭机制.
主要方法:
- 对BK通道的核心-MT构造的长时间原子模拟.
- 在750 mV的电压激活过渡的分析.
- 自由能量分析以确定门电荷.
主要成果:
- 观察到S4螺旋的适度垂直移位 (~3 Å),伴随着显著的横向移动.
- 预测的VSD运动与最近对突变BK通道的Cryo-EM研究一致.
- 计算出每个VSD的总门电荷为0.44e,与实验值一致.
- 确定了大型本地电场梯度作为有效封锁的关键,尽管物理运动很小.
- 通过S4-S5-S6接口揭示了一个非正规的途径,通过S4-S5-S6接口将S4运动与孔隙开放相合.
结论:
- BK通道电压封锁涉及不同的VSD运动和非正规的合路径.
- 适度的物理运动和小的门电荷有效地驱动门由于蛋白质重塑的电场.
- 这些发现为其他离子通道与非域互换VSD的电压封闭机制提供了洞察力.
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