Optimizing Antimicrobial Peptide Design: Integration of Cell-Penetrating Peptides, Amyloidogenic Fragments, and Amino...

The escalating threat of multidrug-resistant pathogens necessitates innovative approaches to combat infectious diseases. In this study, we examined peptides R23F^S*, V31K^S*, and R44K^S*, which were engineered to include an amyloidogenic fragment sourced from the S1 protein of S. aureus, along with one or two cell-penetrating peptide (CPP) components. We assessed the antimicrobial efficacy of these peptides in a liquid medium against various strains of both Gram-positive bacteria, including S. aureus (209P and 129B strains), MRSA (SA 180 and ATCC 43300 strains), and B. cereus (strain IP 5832), and Gram-negative bacteria such as P. aeruginosa (ATCC 28753 and 2943 strains) and E. coli (MG1655 and K12 strains). Peptides R23F^S*, V31K^S*, and R44K^S* exhibited antimicrobial activity comparable to gentamicin and meropenem against all tested bacteria at concentrations ranging from 24 to 48 μM. The peptides showed a stronger antimicrobial effect against B. cereus. Notably, peptide R44K^S* displayed high efficacy compared to peptides R23F^S* and V31K^S*, particularly evident at lower concentrations, resulting in significant inhibition of bacterial growth. Furthermore, modified peptides V31K^S* and R44K^S* demonstrated enhanced inhibitory effects on bacterial growth across different strains compared to their unmodified counterparts V31K^S and R44K^S. These results highlight the potential of integrating cell-penetrating peptides, amyloidogenic fragments, and amino acid residue modifications to advance the innovation in the field of antimicrobial peptides, thereby increasing their effectiveness against a broad spectrum of pathogens.