A Unique Phage DUF669 Protein mediates Post-cleavage Repair Against Host CRISPR Immunity

Phages have evolved various anti-CRISPR(Acr) proteins evade hosts’ immunity by direct CRISPR interference. However, whether other counter-CRISPR mechanisms exist remains unexplored. Here, we report a phage-encoded two-protein system, Healer, which neutralizes CRISPR immunity via a post-cleavage DNA repair mechanism. This phage replication-associated system comprises two proteins: Gp63 (a DUF669 domain-containing protein), and Gp64 (a AAA domain). Mechanistic investigations elucidate that Gp63 acts as a rapid-response effector of CRISPR-induced DNA break, following the binding of ssDNA allows the Gp64 to mediate homologous recombination, repairing CRISPR-induced phage DNA break and enabling phage survival. Notably, co-expression Healer system with CRISPR-Cas9/Cas12 in E. coli, P. aeruginosa, and A. baumannii, demonstrated higher phage genome-editing efficiency. Conclusively, our findings represent a vital anti-CRISPR complementary strategy, providing a promising tool for genome manipulation.