通过NMR确定的转位酶电机SecA对信号序列识别的结构基础
Ioannis Gelis1, Alexandre M J J Bonvin, Dimitra Keramisanou
1Department of Chemistry, Rutgers University, Newark, NJ 07102, USA.
Cell
|November 21, 2007
概括
研究人员阐明了信号如何与SecA结合,Sec转位酶的运动蛋白. 这种结合对于蛋白质出口至关重要,并且涉及SeCA上的特定槽,揭示了细胞蛋白质运输的洞察力.
科学领域:
- 分子生物学分子生物学
- 蛋白质生物化学 蛋白质生物化学
- 细胞运输机制 细胞运输机制
背景情况:
- 蛋白质出口对于细胞功能至关重要,它依赖于受体识别的信号序列.
- Sec转位酶系统,特别是SecA ATPase电机,在蛋白质转位中起着至关重要的作用.
- 通过SeCA识别信号序列的精确机制在很大程度上仍未定义.
研究的目的:
- 通过SeCA确定信号识别的结构基础.
- 阐明SecA结构在调解蛋白质转位中的作用.
- 通过其C端尾和SecB伴侣来研究SecA活动的调节.
主要方法:
- 使用NMR光谱学测定信号-SecA复合物的溶液结构.
- 结合相互作用的分析,包括疏水力和静电力.
- 功能性测试用于评估信号结合中断时的转位缺陷.
主要成果:
- 信号在SeCA中与柔性沟结合时采用了α-螺旋结构.
- SecA通过这种槽内的疏水和静电相互作用来识别各种信号序列.
- 信号对Seca的结合受损导致显著的蛋白质转位缺陷.
- SecA的C端尾抑制了结合,这一过程由SecB伴侣缓解.
- 在溶液中,SecA存在两种不同的构造,这表明它具有动态转位机制.
结论:
- 该研究揭示了信号与Seca结合的结构机制,这是蛋白质出口的关键步骤.
- SecA的灵活槽作为各种信号序列的通用识别网站.
- 通过C端尾部和SecB陪伴器调节SecA活动的调节.
- SecA的 conformational 动力学提供了对多转位过程的洞察.
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