一个基于FRET的传感器揭示了ATP水解诱导的大型形状变化和分子电机髓酸三种不同的状态
W M Shih1, Z Gryczynski, J R Lakowicz
1Department of Biochemistry, Stanford University School of Medicine, California 94305, USA.
Cell
|September 28, 2000
概括
分子菌素电机在它们的轻链结合区域中经历了巨大的角度变化,揭示了两个不同的前冲动状态. 这些状态是由结合的-腺二酸 (Mg.ADP.Pi) 诱导的,而不是-腺三酸 (Mg.ATP).
科学领域:
- 生物化学 生物化学
- 分子生物学分子生物学
- 生物物理学的生物物理.
背景情况:
- 分子电机肌肉素对于细胞运动至关重要.
- 肌的拟议机制涉及其光链结合区域在actin相互作用期间的大角度摆动.
- 以前的动态测量并没有完全捕捉到这个拟议的大角度变化.
研究的目的:
- 直接测量肌酸蛋白的轻链结合区域的核酸依赖角度变化.
- 为了研究肌肉素在其功能周期期间的构造状态.
- 为了澄清核酸结合在肌肉素中风前状态中的作用.
主要方法:
- 氨酸工程来创建特定的标签站点.
- 开发一种基于高分辨率的Förster共振能量转移 (FRET) 传感器.
- 结合了稳定状态和时间解析的FRET测量.
主要成果:
- 在轻链结合区域中检测到大约70度的核酸依赖角度变化.
- 两种不同的肌肉素中风前状态出乎意料地被揭示出来.
- 结合的Mg.ADP.Pi,而不是Mg.ATP,被发现可以诱导这些中风前状态.
结论:
- 肌经历了显著的形状变化,验证了拟议的大角度运动.
- 肌肉素中风前的状态是由Mg.ADP.Pi.Pi的存在调节的.
- 这一发现为肌肉蛋白运动功能和核酸相互作用的机制提供了新的见解.
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