不对称的形状和脂质相互作用塑造了异构体ABC载体的ATP合循环
bioRxiv : the preprint server for biology
|July 3, 2023
概括
这项研究揭示了像BmrCD这样的ABC输送器中的不对称构造如何驱动催化不对称,并塑造运输能量. 脂质相互作用调节这些状态,影响整体的运输机制.
科学领域:
- 结构生物学 结构生物学
- 生物化学 生物化学
- 膜运输 运输 膜运输
背景情况:
- 异构体ABC输送体在细胞运输中起着至关重要的作用,但它们的催化不对称性和构造动力学仍然不完全理解.
- 了解这些机制对于破译多药性耐药性和开发向疗法至关重要.
研究的目的:
- 阐明异构体ABC输送器中催化不对称的结构基础.
- 调查这种不对称性如何影响构造周期的能量.
- 描述脂质-蛋白质相互作用在调节载体功能的作用.
主要方法:
- 低温电子显微镜 (cryo-EM) 用于确定BmrCD的高分辨率结构.
- 双电子-电子共振 (DEER) 光谱法用于分析形态群体.
- 分子动力学 (MD) 模拟以探测结构动力学和脂质相互作用.
主要成果:
- 确定了多个向内面的 (IF) 和BmrCD.的封闭 (OC) 形状.
- 观察到由ATP驱动的同质化,涉及从跨膜到核酸结合域的子单元对称性的变化.
- 未覆盖的不对称基质和Mg2+结合,可能触发优先ATP水解.
- 证明了与IF和OC状态的差异性脂质结合,调节稳定性.
结论:
- 脂质相互作用显著影响BmrCD形状的能量格局和稳定性.
- 非对称的形状是ABC载体的ATP合运输周期的核心.
- 这些发现提供了一个新的运输模型,对理解ABC运输机制有广泛的影响.
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