Phosphorylation as an Effective Tool to Improve Stability and Reduce Toxicity of Antimicrobial Peptides

Developing a straightforward and effective strategy to modify antimicrobial peptides (AMPs) is crucial in overcoming the challenges posed by their instability and toxicity. Phosphorylation can reduce toxicity and improve the stability of AMPs. Based on these, we designed a series of peptides and their corresponding phosphorylated forms. The results showed that all phosphorylated peptides displayed reduced toxicity and enhanced stability compared to their unphosphorylated counterparts. Among them, W₃BipY₈-P stood out as the most promising peptide, exhibiting similar antibacterial activity as its unphosphorylated analog W₃BipY₈ but with significantly reduced hemolytic activity (19-fold decrease), cytotoxicity (3.3-fold decrease), and an extended serum half-life 6.3 times longer than W₃BipY₈. W₃BipY₈-P exerted bactericidal effects by disrupting bacterial membranes. Notably, W₃BipY₈-P significantly prolonged the survival of bacteria-infected animals while its LD₅₀ was 4.2 times higher than that of W₃BipY₈. These findings highlight phosphorylation as an effective strategy for improving the antimicrobial properties of AMPs.