A N-methylated antimicrobial peptide targets the fructose transporter FruA of Staphylococcus aureus

Antimicrobial peptides (AMPs) represent promising alternatives to conventional antibiotics, but their therapeutic application is often hindered by suboptimal stability and poorly defined mechanisms of action. To overcome these limitations, we engineered a peptide named CAMP502NC3 through chemical modification of its parent peptide, CAMP502, which originates from marine biofilm microorganisms. The design included N-terminal acetylation, C-terminal amidation, and N-methylation of the lysine at position 3 to improve stability. CAMP502NC3 demonstrated potent activity against Staphylococcus aureus and remained stable under diverse conditions, including varying pH, high salinity, and protease exposure. Mechanistically, CAMP502NC3 leads to bacterial membrane depolarization. Transcriptomic and biochemical analyses further revealed that it interferes with key metabolic pathways, notably the fructose-specific phosphotransferase system. Molecular docking indicated direct binding of CAMP502NC3 to the fructose transporter FruA. This study illustrates how rational peptide engineering can generate stable and potent AMPs with precise membrane-associated targets, as exemplified by CAMP502NC3.