杆菌的子域Cag T4SS外膜核心复合体表现出结构独立性
Jacquelyn R Roberts1,2, Sirena C Tran3,4, Arwen E Frick-Cheng1
1Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA.
Life science alliance
|April 17, 2024
概括
杆菌杆菌Cag的IV型分泌系统.
科学领域:
- 微生物学 微生物学
- 结构生物学 结构生物学
- 分子生物学分子生物学
背景情况:
- 杆菌Cag型IV分泌系统 (Cag T4SS) 对于胃癌的发病过程至关重要.
- Cag T4SS外膜核心复合体 (OMCC) 包括一个外膜盖 (OMC),一个周等离子环 (PR) 和一个茎.
- OMC由CagY,CagX,CagT,CagM和Cag3组成,而PR由CagY和CagX组成.
研究的目的:
- 调查CagT,CagM和CagY的天线投影 (AP) 区域在OMCC的结构组织中的作用.
- 了解特定的Cag T4SS组件对OMCC的不同子域的贡献.
主要方法:
- 单粒子冷电子显微镜 (cryo-EM) 用于分析野生类型 (WT) 和突变的Cag T4SS OMCC.
- 突变包括缺乏CagT (ΔcagT),CagM (ΔcagM) 的菌株和一个CagY天线投影突变 (CagY∆AP).
主要成果:
- 来自 ΔcagT 和 ΔcagM 突变的复合体缺乏有组织的 OMC,但 PR 仍然有结构.
- CagY∆AP突变的OMCC与WT相似,只有缺少α螺旋天线投影而有所不同.
- 仅CagY和CagX就足以稳定PR,但OMC组织需要CagY,CagX,CagM和CagT.
结论:
- CagY和CagX对于周等离子体环结构至关重要.
- 与CagY和CagX一起,CagT和CagM对于外膜盖组织是必要的.
- 这项研究揭示了Cag T4SS OMCC.的PR和OMC子域之间的令人惊的结构独立性.
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