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混合注射XFEL序列晶体学的核糖核酸切换反应状态的结构

J R Stagno¹, Y Liu¹, Y R Bhandari¹

¹Protein-Nucleic Acid Interaction Section, Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702, USA.

|November 15, 2016

概括

研究人员使用X射线自由电子激光 (XFEL) 脉冲来捕获腺素核突变的实时结构变化. 这种方法揭示了基因表达调节的动态机制,在配体结合过程中显示出不同的RNA构造.

科学领域:

结构生物学
生物化学
分子生物学

背景情况:

核糖突变是控制基因表达的RNA调节元件.
结合于 рибо开关的连接物诱导了信号基因表达的结构变化.
了解这些动态结构变化对于解读基因调节机制至关重要.

研究的目的:

调查结合体结合过程中的 ribowitches 的时间解析结构动态.
阐明从aptamer到表达平台的信号传输机制.
证明femtosecond XFEL晶体学对于研究生物分子反应的有用性.

主要方法:

使用5秒X射线自由电子激光 (XFEL) 脉冲进行时间分辨率晶体学.
采用了氨酸 рибо开关体域的微和纳米晶体.
"混合注入"串行晶体学能够在特定时间点 (10秒到10分钟) 捕捉反应.

主要成果:

确定了4种不同的腺转接合酶的结构状态,包括Apo和联体结合的形式.
在10秒的延迟下捕获的中间结构显示了初始的带结合口袋调整.
观察到显著的形状变化,导致10分钟后空间组转化为最终的联体结合状态.
支持至少涉及四个状态的反应机制模型.

结论:

对于研究快速生物分子相互作用而言,Femtosecond XFEL时间分辨率晶体学是有效的.
这项研究揭示了基因调节的基因结构重组.
微和纳米晶体适用于对联体诱导的形状变化的时间解析衍射研究.

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