由时间解析的冷EM直接显示的肌肉素的摆动杆机制
David P Klebl1,2,3, Sean N McMillan2,4,5, Cristina Risi6
1School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, UK.
Nature
|April 9, 2025
概括
研究人员使用时间解决的冷EM观察了初始启动的actomyosin状态,揭示了actin结合如何通过结构变化和杆摆动驱动肌运动和力量产生.
科学领域:
- 分子和细胞生物学
- 生物物理
- 结构生物学
背景情况:
- 通过F-actin相互作用产生细胞力量和运动.
- 运动与动因催化肌状态转换和杆摆动有关.
- 初始启动的actomyosin状态和actin的催化机制尚不清楚.
研究的目的:
- 为了观察未表征的原始性actomyosin状态.
- 阐明动因催化肌酸ATPase活动的机制.
- 解决肌肉细胞的结构转变.
主要方法:
- 使用时间解析式冷电子显微镜 (cryo-EM).
- 使用缓慢水解产物释放的髓-5突变体.
- 伪原子模型被安装在冷电磁图上进行详细的解释.
主要成果:
- 在混合后的10毫秒内捕获了原始的actomyosin状态,在动力冲击后的120毫秒之前.
- 乙烯酸结合于肌蛋白的下50kDa子域打开裂并抑制酸盐的释放.
- 上方50kDa的亚域与素的相互作用将关闭裂,使酸盐释放,并形成强结合界面以产生力.
- 肌蛋白-5杆臂以93°的速度旋转,主要沿着行为轴旋转,与其步骤长度相匹配.
结论:
- 时间解析的结构揭示了肌运动的摆动杆机制.
- 已经阐明了肌肉素功率冲击过程中的结构转换.
- 这项研究解决了长期存在的问题,
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