Abstact

Antimicrobial drug resistance poses a global health challenge that necessitates the identification of new druggable targets(1-3). The essential lipid II flippase MurJ is a promising yet underexplored antimicrobial target in bacterial cell wall biosynthesis(4-7). The only known inhibitors of Gram-negative (diderm) MurJ are the single-gene lysis proteins (Sgls) from the lytic single-strand RNA phages M (Sgl(M)) and PP7 (Sgl(PP7))(8,9). Sgl(M) and Sgl(PP7) have distinct evolutionary origins and share no sequence similarity. Here we describe a common mechanism of MurJ inhibition by these phage-encoded Sgls. We determined the structures of MurJ-bound Sgl(M) and Sgl(PP7) and discovered a third distinct MurJ-targeting Sgl from the predicted phage Changjiang3 (Sgl(CJ3)) that we also characterized structurally. Our findings demonstrate that all three Sgls evolved convergently to trap MurJ in a periplasm-open conformation through a common MurJ interface, revealing a pathway for drug design.