Multiarmed Radially Amphiphilic Antimicrobial Polypeptides Enable Enhanced Recognition of Bacterial Phospholipid

The differences in the phospholipid profile between bacterial and mammalian membranes present a promising direction for designing antimicrobial peptides (AMPs). A key challenge, however, is engineering AMPs with a high affinity for bacterial anionic phospholipid (phosphatidylglycerol, PG) while minimizing off-target interactions with mammalian phosphatidylserine (PS). Herein, we report a multiarmed radially amphiphilic AMP (maRAP) design that enhances PG recognition, exhibiting potent antibacterial activity and exceptional antibacterial selectivity. Compared to the single-arm RAP (1aRAP), maRAPs exhibited superior affinity for PG, yet they exhibited negligible binding to PS. They also demonstrated significantly enhanced bactericidal efficacy and selectivity over 1aRAP in complex physiological environments. In the murine bladder-infection model, maRAPs more effectively reduced the bacterial load and attenuated infection-induced tissue damage, as demonstrated by an intact urothelial lining and minimal lamina propria edema at the infection site. This work presents the multiarm strategy as an effective approach for advanced AMP development.