Researchers discovered that unrelated bacteriophages disable the essential bacterial cell‑wall protein MurJ by locking it into a single conformation, halting peptidoglycan assembly and causing cell death. High‑resolution imaging mapped how viral proteins bind and freeze MurJ’s structure, defining a molecular kill switch that directly impairs bacterial survival. The work identifies MurJ as a tractable antibacterial target distinct from existing classes and suggests viral‑derived inhibitors or small molecules that mimic the locking mechanism could be developed. The study employed cryo‑EM imaging and functional assays to validate the mechanism across bacterial species. Antibiotic discovery teams should evaluate MurJ‑targeting strategies as a route to new bactericidal mechanisms, while medicinal chemists will need to address cell‑penetration and resistance potential in early lead optimization.