通过150秒的时间分辨率X射线晶体学观察蛋白质的功能
Friedrich Schotte1, Manho Lim, Timothy A Jackson
1Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
Science (New York, N.Y.)
|June 21, 2003
概括
我们使用X射线衍射观察了肌球蛋白 (Mb) L29F突变蛋白的快速结构变化. 这种突变体的CO中间寿命比野生类型的Mb要短1000倍,显示出动态蛋白质运动.
科学领域:
- 结构生物学 结构生物学
- 生物物理学的生物物理.
- 蛋白质动力学 蛋白质动力学
背景情况:
- 肌球蛋白 (Mb) 对于氧气运输至关重要.
- 了解Mb的配体结合和释放动态是蛋白质功能的关键.
- 之前的研究缺乏关于这些动态的高分辨率,时间分辨率数据.
研究的目的:
- 为了研究肌球蛋白L29F突变的皮秒级结构演变.
- 为了阐明 L29F MbCO 释放一氧化碳 (CO) 的机制.
- 为了将蛋白质构造变化与连接体动力学相关联.
主要方法:
- 在1.8安格斯特罗姆分辨率下,以皮秒时间解析的X射线衍射.
- 闪光照相分析的L29F MbCO.CO.的时间分辨率中红外光谱.
- 分析电子密度图以可视化短暂状态.
主要成果:
- 观察到L29F Mb突变体的框架逐框架结构演变.
- 确定了一种短暂的CO中间体,寿命为140秒,比野生类型短1000倍.
- 在CO释放过程中揭示了剧烈的形状变化和相关的侧链运动.
结论:
- 这种L29F突变显著加速了CO与肌球蛋白分离的过程.
- 蛋白质的结构变化远远超过了脱氧和碳氧状态之间的变化.
- 侧链动态在肌球蛋白中迅速排放连接体方面发挥着关键作用.
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