PEGylation of the Antimicrobial Peptide PG-1: A Link between Propensity for Nanostructuring and Capacity of the Antitrypsin Hydrolytic Ability

The increasing prevalence of antibacterial resistance globally underscores the urgent need for updated antimicrobial peptides (AMPs). Here, we describe a strategy for inducing the self-assembly of protegrin-1 (PG-1) into nanostructured antimicrobial agents with significantly improved pharmacological properties. Our strategy involves PEGylation in the terminals of PG-1 and subsequent self-assembly in aqueous media in the absence of exogenous excipients. Compared with the parent PG-1, the therapeutic index (TI) of NPG750(TIGram-negative bacteria = 17.07) and CPG2000(TIAll = 26.02) was increased. Importantly, NPG750 and CPG2000 offered higher stability toward trypsin degradation. Mechanistically, NPG750 and CPG2000 exerted their bactericidal activity by membrane-active mechanisms due to which microbes were not prone to develop resistance. Our findings proved PEGylation as a simple yet versatile strategy for generating AMP-derived bioactive drugs with excellent antitrypsin hydrolytic ability and lower cytotoxicity. This provides a theoretical basis for the further clinical application of AMPs.