Positive Charge-Concentrated Dimeric Lipopeptides with Enhanced Protease Resistance: A Potential Solution for Systemic Bacterial Infections

Antimicrobial peptides (AMPs) show potential as antibiotic alternatives for bacterial infections; nevertheless, the susceptibility to proteases limits their broader utilization. This study developed engineered lipopeptides using antienzymolysis modifications and cysteine (Cys)-dimerization strategy. As the key parameters for the functioning of AMPs, hydrophobicity and positive charges were concentrated within the peptide sequence by adjusting the intermolecular disulfide bond placement to study their distribution effects. Their centralization in the sequence induces a differential propensity of engineered lipopeptides toward bacterial membranes. Positive charge-concentrated dimeric lipopeptide (C-C₁₀)_C-C displayed strong resistance to various proteases, and demonstrated excellent stability and activity in vitro, effectively eliminating systemic bacterial infections in mice without eliciting in vivo toxicity. The bactericidal effects of (C-C₁₀)_C-C were achieved through a synergistic mechanism involving membrane cleavage and the inhibition of energy metabolism. In summary, these advances offered valuable insights into enhancing the protease resistance of AMPs and the potential for modifying peptide-based biomaterials through Cys-dimerization.