基质与在不对称的细菌蛋白酶激活剂Bpa环上的残留物结合
Tatjana von Rosen1, Rafal Zdanowicz1,2, Yasser El Hadeg1
1Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland.
Nature communications
|March 29, 2025
概括
研究人员可视化了Mycobacterium结核病蛋白酶激活剂Bpa与其基质HSPR相互作用,使用冷EM. 这揭示了蛋白质降解的关键相互作用,对细菌的持久性至关重要.
科学领域:
- 微生物学 微生物学
- 结构生物学 结构生物学
- 生物化学 生化学
背景情况:
- 菌根菌具有通过横向基因转移获得的独特蛋白质体,对于菌根结核病菌在宿主巨细胞中的生存至关重要.
- 蛋白质体核心粒子 (20S CP) 与激活器复合体一起通过细菌蛋白质体激活器Bpa.通过激活器Bpa.通过激活器复合体来降解蛋白质,包括热冲击抑制器HSPR.
- Bpa促进HspR的ATP独立降解,这是细菌持久性的关键过程.
研究的目的:
- 确定细菌蛋白酶激活剂Bpa及其基质HSPR之间形成的复合物的高分辨率3D结构.
- 阐明调控Bpa介导基质识别和蛋白质体降解的分子相互作用.
- 了解Bpa与20S蛋白酶体核心粒子相互作用的结构基础.
主要方法:
- 使用冷电子显微镜 (cryo-EM) 来获得Bpa-HspR复合物的3D重建,分辨率为4.1 Å.
- 进行结构引导的位点导向突变发生,以调查已识别的相互作用残留物的功能意义.
- 实验室生化分析被用于确认特定残留物在基质招募和降解中的作用.
主要成果:
- 冷-EM结构揭示了Bpa与HSPR相互作用的特定区域,提供了对基质结合的见解.
- 突变和生化分析证实了Bpa在招募HspR和促进其降解中的作用所确定的残留物的重要性.
- 观察到十二角形Bpa环与20S CP的七角形α环不对称地结合,形成一个"盖"形状,同时参与所有对接点.
结论:
- 这项研究为Bpa-HspR相互作用提供了第一个结构洞察力,详细介绍了蛋白酶激活器如何招募其基质.
- 这些发现突出了特定氨基酸残留在介导基质识别和由真菌细菌蛋白酶体降解中的关键作用.
- Bpa与20S CP的不对称关联表明,Mycobacterium tuberculosis中调节蛋白质体活动的独特机制.
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