通过细菌cGAS类似的结合增强了抗菌体防御
Justin M Jenson1,2, Tuo Li1,2,3, Fenghe Du1,2,3
1Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA.
Nature
|February 27, 2023
概括
细菌使用类似于泛素的机制来控制对菌体感染的cGAS酶活性. 这涉及蛋白质结合以促进循环GMP-AMP (cGAMP) 的产生,然后通过隔离cGAMP来抵消菌体.
科学领域:
- 微生物学
- 分子生物学
- 免疫学
背景情况:
- 循环GMP-AMP合成酶 (cGAS) 通过在DNA检测时产生cGAMP,对脊椎动物的免疫防御至关重要.
- 细菌具有基于循环二核酸 (CDN) 的反菌信号系统 (CBASS),涉及类似cGAS的酶和效应器来对抗菌感染.
- 一些CBASS系统包括Cap2和Cap3蛋白质,同类于ubiquitin-conjugating酶,但它们的抗菌素机制尚不清楚.
研究的目的:
- 阐明细菌CBASS中的Cap2和Cap3蛋白质的抗菌机制.
- 研究细菌cGAS类酶在菌体感染期间如何调节.
- 了解细菌对菌体和病毒抗策略的分子基础.
主要方法:
- 使用生物化学测试研究了Cap2和cGAS之间的相互作用.
- 分析了Cap2介导的结合对cGAMP产生的影响.
- 采用基因查来识别对抗细菌cGAS信号的菌体蛋白.
- 确定与cGAMP结合的菌体蛋白质的晶体结构.
主要成果:
- 证实Cap2通过基结结合cGAS以向蛋白质,模仿无处不在的结合.
- 表明这种对应的cGAS修饰增强了循环GMP-AMP (cGAMP) 的产生.
- 鉴定了一种菌体蛋白,Vs.4,它与cGAMP紧密结合,
- 揭示了Vs.4与cGAMP结合的六边形结构,解释了其抑制机制.
结论:
- 细菌的cGAS活性由一个涉及Cap2的全方位合机制来调节.
- 细菌对菌体的防御包括调节周期性二核酸水平.
- 菌体已经进化出像Vs.4这样的机制,通过干扰cGAMP信号来抵消细菌的防御,这突显了进化军备竞赛.
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