通过SIR2效应线组件激活Thoeris抗病毒系统
Giedre Tamulaitiene1, Dziugas Sabonis2, Giedrius Sasnauskas2
1Institute of Biotechnology, Life Sciences Center, Vilnius University, Vilnius, Lithuania. giedre.tamulaitiene@bti.vu.lt.
Nature
|February 21, 2024
概括
细菌使用像Thoeris这样的防御系统对抗菌体 (菌体) 感染. 这项研究揭示了Thoeris效应器ThsA在结合循环ADP核糖信号时如何通过丝组合激活,从而导致NAD+的快速耗尽.
科学领域:
- 分子生物学
- 生物化学
- 结构生物学
背景情况:
- 细菌拥有复杂的抗菌体防御系统来对抗病毒感染.
- 一个值得注意的防御机制Thoeris系统包括传感器 (ThsB) 和效应器 (ThsA) 模块.
- 尽管有结构数据,但ThsA的激活机制仍然不清楚,特别是它与循环分子gcADPR的相互作用.
研究的目的:
- 为了阐明Thoeris效应蛋白的激活机制,ThsA.
- 确定合成的循环分子1′-3′糖循环ADP核糖 (gcADPR) 如何触发ThsA的效应函数.
- 了解ThsA激活的结构基础及其在细菌防御中的作用.
主要方法:
- 在实验室中使用二元ThsB'蛋白合成1'-3'gcADPR.
- 低温电子显微镜 (cryo-EM) 用于确定激活的ThsA的结构.
- 评估NAD+水解和ThsA线索形成的生物化学试验.
主要成果:
- 1'-3' gcADPR 与 ThsA 的 SLOG 域结合,并启动其激活.
- 激活的ThsA经历了四边体的螺旋丝组装.
- 低温EM结构显示,线组合稳定了活跃的SIR2域结构,促进了NAD+的快速耗尽.
- ThsA对gcADPR表现出类似开关的反应,这种反应由线索形成介导.
结论:
- 细菌防御蛋白ThsA通过gcADPR结合被激活,导致丝组装.
- 导线形成使ThsA在其活性构成中稳定,使NAD+有效的水解成为可能.
- 托埃里斯系统采用信号依赖的,类似开关的机制来进行强大的抗菌体防御.
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