从PorKN轮结构与PorG结合的第九类分泌物和附着复合物的洞察力
Dhana G Gorasia1, Eric Hanssen2,3,4, Manasi Mudaliyar3,4
1Oral Health Cooperative Research Centre, Melbourne Dental School, The Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC, Australia. gorasiad@unimelb.edu.au.
Nature communications
|August 19, 2025
概括
在Bacteroidota细菌中的第九类分泌系统使用了一种新的轮式机制. 这涉及PorKN环,PorLM电机和PorG相互作用,用于通过外膜输出蛋白质.
科学领域:
- 微生物学 微生物学
- 结构生物学 结构生物学
- 细菌生理学 细菌生理学
背景情况:
- 第九类分泌系统 (T9SS) 对于Bacteroidota.ta.的蛋白质通过外膜输出至关重要.
- 控制T9SS功能的精确分子机制在很大程度上仍未被阐明.
- 关键部件包括Sov转位器,附件复合体 (PorQ,U,V,Z),PorLM电机和PorKN环.
研究的目的:
- 阐明 Porphyromonas gingivalis 的第九类分泌系统的结构基础和机制细节.
- 确定周等离子 PorKN 环的结构及其与其他 T9SS 组件的相互作用.
主要方法:
- 低温电子显微镜 (cryo-EM) 的分辨率为3.5 Å.
- 生物化学分析以确定关键的二硫化物键.
- 附着复合体的定位研究.
主要成果:
- 确定了PorKN周等离子环 (32-33个子单元) 的高分辨率冷EM结构.
- 确定了PorK与外膜蛋白PorG之间的关键二硫化键,对于分泌至关重要.
- 附着复合物被证明可以在PorKN环上方结合.
结论:
- PorKN 环的功能就像一个轮,PorN 投射引入 PorLM 电机.
- 这种相互作用驱动PorKN-PorG复合体的旋转,驱动蛋白质分泌.
- 该系统既促进了蛋白质的出口,也促进了分泌货物的协调细胞表面附着.
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