Molecular basis of bacterial DSR2 anti-phage defense and viral immune evasion

• Published in: Nature communications Vol. 15; no. 1; pp. 3954 - 11
• Main Authors: Huang, Jiafeng, Zhu, Keli, Gao, Yina, Ye, Feng, Li, Zhaolong, Ge, Yao, Liu, Songqing, Yang, Jing, Gao, Ang
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 10.05.2024; Nature Publishing Group; Nature Portfolio
• Subjects: 101/28; 631/326/1321; 631/326/41; 631/326/41/2536; 631/45/607; 631/535/1258/1259; Assembly; Bacillus subtilis - genetics; Bacillus subtilis - immunology; Bacteria; Bacterial Proteins - chemistry; Bacterial Proteins - genetics; Bacterial Proteins - immunology; Bacterial Proteins - metabolism; Bacteriophages - genetics; Bacteriophages - immunology; Cryoelectron Microscopy; Defense; Depletion; Docks; Genomes; Humanities and Social Sciences; Immune Evasion; Models, Molecular; Modules; Molecular modelling; multidisciplinary; NAD - metabolism; Phages; Protein Binding; Proteins; Science; Science (multidisciplinary); Sirtuins - genetics; Sirtuins - metabolism; Viral Proteins - chemistry; Viral Proteins - genetics; Viral Proteins - immunology; Viral Proteins - metabolism
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-024-48291-4

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. The defense-associated sirtuin 2 (DSR2) system protects bacteria from phages by depleting NAD + . Here, authors elucidate the molecular mechanisms underlying DSR2 assembly, activation, and inhibition, providing important insights into bacterial anti-phage defense.