Rational Leucine-Centric Design Confers Enhanced Proteolytic Stability and Reduced Toxicity of Antimicrobial Peptides against Multidrug-Resistant Bacterial Infections

Antimicrobial
peptides (AMPs), emerged as appealing therapeutic
agents against multidrug-resistant (MDR) bacteria, face clinical obstacles
due to unsatisfactory stability and mammalian toxicity. Rational design
approaches capable of balancing the efficacy, stability, and safety
of AMPs are greatly needed. Here, we engineered a series of derivatives
of P-α-02-Ban AMP developed by our groupthrough
site-specific modifications targeting leucine residues to improve
proteolytic stability and reduce toxicity. Notably, the d-Ile substitution in the derivative H-10 synergistically enhanced
proteolytic stability and attenuated toxicity. Further investigations
revealed that H-10 exhibited rapid bactericidal action via membrane
disruption. The bacterial selectivity of H-10 was revealed by molecular
dynamics simulations. In vivo assessments confirmed
its favorable safety profile and pharmacokinetic properties, as well
as significant efficacy against Staphylococcus aureus (MDR) bacterial infections. Collectively, this study positions H-10
as a promising candidate against MDR infection while establishing
leucine-centric design as a valuable paradigm in AMP optimization.