四聚体
枯草芽孢杆菌
先天免疫系统
生物
结构生物学
细胞生物学
化学
免疫系统
遗传学
细菌
生物化学
酶
作者
Jiafeng Huang,Keli Zhu,Yina Gao,Ye Feng,Zhaolong Li,Ge Yao,Songqin Liu,Jing Yang,Ang Gao
标识
DOI:10.1038/s41467-024-48291-4
摘要
Abstract Defense-associated sirtuin 2 (DSR2) systems are widely distributed across prokaryotic genomes, providing robust protection against phage infection. DSR2 recognizes phage tail tube proteins and induces abortive infection by depleting intracellular NAD + , a process that is counteracted by another phage-encoded protein, DSR Anti Defense 1 (DSAD1). Here, we present cryo-EM structures of Bacillus subtilis DSR2 in its apo, Tube-bound, and DSAD1-bound states. DSR2 assembles into an elongated tetramer, with four NADase catalytic modules clustered in the center and the regulatory-sensing modules distributed at four distal corners. Interestingly, monomeric Tube protein, rather than its oligomeric states, docks at each corner of the DSR2 tetramer to form a 4:4 DSR2-Tube assembly, which is essential for DSR2 NADase activity. DSAD1 competes with Tube for binding to DSR2 by occupying an overlapping region, thereby inhibiting DSR2 immunity. Thus, our results provide important insights into the assembly, activation and inhibition of the DSR2 anti-phage defense system.
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