细菌外膜介绍器FimD的生长的交付机制
Minge Du1, Zuanning Yuan1, Hongjun Yu1
1Structural Biology Program, Van Andel Research Institute, Grand Rapids, MI, USA.
Nature
|October 5, 2018
概括
这项研究揭示了像大肠杆菌这样的病原细菌是如何使用伴侣路径来构建的. 低温电磁显示FimD带人蛋白转移子单元,稳定柱子组合.
科学领域:
- 微生物学
- 结构生物学
- 生物化学
背景情况:
- 病原细菌利用表面皮质 (fimbriae) 进行宿主细胞粘附.
- 一种类型的 pili 组件依赖于保留的陪伴者-usher 路径.
研究的目的:
- 阐明从N端到C端域的Pilus子单元传递的机制.
- 了解生物发生过程中子单元聚合的时间.
主要方法:
- 使用冷电子显微镜 (cryo-EM) 可视化一个关键的柱子组装中间体.
- FimD-FimC-FimF-FimG-FimH复合物的结构分析.
主要成果:
- 一个结构中间体捕获了FimD,将堆端转移到其C端域 (CTD1和CTD2).
- FimD的N端域与CTD2结合,同时保持与FimF的联系,从而促进子单元的接入.
- 在交付过程中,FimD的N端尾从螺旋转向循环,以绑定CTD2.
结论:
- 该研究提出了一种通过FimD域的双结合来稳定柱状组装中间体的机制.
- 这种稳定性可以防止多个子单元在合并过程中发生柱状纤维解离.
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