一个三方蛋白质复合体的结构,该复合体将毒素向第七类分泌系统
Timothy A Klein1,2, Prakhar Y Shah1,2, Polyniki Gkragkopoulou1,2
1Michael DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON L8S 4K1, Canada.
概括
第七类分泌系统 (T7SS) 使用LXG域和拉普蛋白导出细菌毒素. 这项研究揭示了LXG域结构,揭示了多种细菌之间保存的出口机制.
科学领域:
- 微生物学 微生物学
- 结构生物学 结构生物学
- 细菌病原体的产生
背景情况:
- 七型分泌系统 (T7SS) 对于格拉姆阳性细菌分泌效应蛋白至关重要.
- 许多T7SS效应器含有Leu-x-Gly (LXG) 域和毒素域,抑制细菌竞争者.
- 之前的研究表明,LXG效应器需要拉普蛋白用于T7SS依赖的出口.
研究的目的:
- 通过T7SS.阐明LXG效应器出口的结构基础.
- 描述LXG域及其同类拉普蛋白之间的相互作用.
- 为了确定Gram阳性细菌中效应体出口的保存机制.
主要方法:
- 使用X射线晶体学确定了与拉普蛋白复合的TelA毒素LXG域的2.6 Å结构.
- 结构分析侧重于确定关键相互作用和保存特征.
- 与其他T7SS效应器综合体进行了比较结构分析.
主要成果:
- 该结构揭示了LXG域的延长型α螺旋捆,在两端均由拉普蛋白调解的广泛的疏水接触.
- 来自Mycobacterial ESX系统的LXG-Lap复合体和PE-PPE异构体之间发现了惊人的结构相似性.
- 这表明一个保留的三方分泌信号涉及LXG域和拉普因子.
结论:
- 该LXG域,与拉普准因子复合,形成一个三方分泌信号,为一个广泛的T7SS毒素家族.
- 在使用T7SS.SS.的各种格拉姆阳性细菌中,存在一种对效应体出口的保存机制.
- 这一发现推动了我们对细菌蛋白质分泌和毒素演变的理解.
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