弗拉盖林诱导的NAIP5激活的结构基础
Bhaskar Paidimuddala1, Jianhao Cao1, Liman Zhang1
1Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, Portland, OR 97239, USA.
bioRxiv : the preprint server for biology
|July 3, 2023
概括
NAIP/NLRC4炎症体通过NAIP5结合细菌鞭毛素 (FliC) 的"陷和锁"机制来激活. 这种结合会诱导NAIP5的结构变化,从而启动NLRC4炎症酶激活.
科学领域:
- 这是天生的免疫力.
- 炎症有一些生物学.
- 结构生物学是结构生物学.
背景情况:
- NAIP/NLRC4炎症酶对检测格拉姆阴性细菌至关重要.
- 细菌连接体的NAIP激活启动下游免疫信号.
- 在联体结合时NAIP形状变化的确切机制尚不清楚.
研究的目的:
- 阐明NAIP5结合其连接体FliC (鞭毛菌素) 的分子机制.
- 为了确定NAIP5结构变化的结构基础,在带结合时.
- 了解NAIP激活如何导致NLRC4炎症酶参与.
主要方法:
- 研究了非活性NAIP5.5的联结区域的动态.
- 在2.93 Å分辨率下解决了NAIP5与FliC结合的冷电子显微镜 (cryo-EM) 结构.
主要成果:
- 揭示了NAIP5.5对FliC认可的"陷和锁"机制.
- 确定了特定的相互作用:FliC-D0C被困在一个疏水口袋中,被NAIP5的插入域 (ID) 和C端尾 (CTT) 锁定.
- 在NAIP5中,FliC结合会诱导形状变化,将ID,HD2和LRR域结合在一起,以激活为NLRC4激活的翅膀螺旋域 (WHD).
结论:
- FliC绑定通过组装灵活的域 (ID,HD2,LRR) 来诱导NAIP5中的结构变化.
- 这种形状变化稳定了WHD循环,使NLRC4炎症酶激活成为可能.
- 阐明了由天生的免疫系统识别细菌病原体的关键步骤.
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