冷EM结构揭示了Arp3释放的酸盐如何削弱由Arp2/3复合体形成的活性丝分支
Sai Shashank Chavali1, Steven Z Chou2,3, Wenxiang Cao1
1Department of Molecular Biophysics and Biochemistry, Yale University, PO Box 208103, New Haven, CT, 06520-8103, USA.
Nature communications
|March 6, 2024
概括
Arp2/3 复杂结构揭示了分支的活性丝是如何形成的,这对于细胞运动至关重要. 它的过渡状态表明,在分支过程中,actin线程的稳定性如何发生变化.
科学领域:
- 细胞生物学 细胞生物学
- 结构生物学 结构生物学
- 生物化学 生物化学
背景情况:
- Arp2/3 复合体对于核化分支性亚丁丝是必不可少的,驱动关键的细胞过程,如运动和形状变化.
- 了解Arp2/3复合体功能的精确结构机制是解读细胞中actin动态的关键.
研究的目的:
- 为了确定来自S. pombe的成熟Arp2/3复杂分支结的高分辨率冷电子显微镜 (cryo-EM) 结构.
- 为了阐明Arp2/3复杂相互作用与母和女儿actin丝的结构基础.
- 为了研究在酸盐释放过渡状态期间的结构变化.
主要方法:
- 电子显微镜 (cryo-EM) 用于在2.7 Å和3.2 Å分辨率下确定结构.
- 使用酸盐模拟物 (BeFx) 来捕获ADP-Pi过渡状态的生物化学分析.
主要成果:
- 获得了S. pombe Arp2/3复杂成熟分支结及其ADP-BeFx过渡状态的高分辨率结构.
- 过渡状态结构显示了Arp3的外部域的旋转和与actin纤维的接触的改变.
- 与Arp2/3复合体结合的母行为丝呈现轻微的曲和扭曲,表明它更喜欢曲的细丝.
结论:
- 无机酸盐 (Pi) 从ADP-Pi 过渡状态中解离,减少了Arp2/3复杂的相互作用与行为丝.
- 这种相互作用的减少可能解释了在ADP-bound状态下成熟的分支结的较低机械稳定性.
- 观察到的母线丝曲和扭曲提供了关于actin线丝力学和Arp2/3复杂结合偏好的见解.
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