Scientists made a human version of the natural antimicrobial peptide LL‑37 and used computer modeling and lab tests to see how it sticks to a bacterial enzyme called PagP. They found that LL‑37 binds tightly to PagP, mainly through certain amino acids, and this binding may block the enzyme’s activity, giving the peptide stronger antibacterial effects.

BACKGROUND The aim of this study was to investigate the antimicrobial property of peptide LL-37 sequences. MATERIAL AND METHODS Humanized antibacterial peptide LL-37 and the mutant were prepared by chemical synthesis. The physicochemical properties of antibacterial peptide LL-37 were analyzed by SWISS-MODEL online prediction tool. Molecular docking between antibacterial peptide LL-37 fragments and palmitoyl transferase PagP was made with Lamarckian genetic algorithm by AutoDock1.5.6. RESULTS The systems contacted each other at 8.75 picosec. After 20 picsec, the system had no trend of dissociation, and the bond energy of weak bond -C-O-H…NH2-CH2- was calculated. The hydrophobic groups were important factors that led to contact and merged the two parts. The contacted weak bond -C-O-H…NH2-CH2- was the bridge for contacting LL-37 with palmitoyl transferase PagP. The binding sites of antibacterial peptide LL-37 and palmitoyl transferase PagP mainly included LYS8, GLU11, LEU28, LYS12, PHE27, ILE13, and PHE6 of antibacterial peptide LL-37 and ARG94, TRP89, ASN65, SER3, GLU90, GLU90, ASN100, HIS102, and THR92 of palmitoyl transferase PagP. CONCLUSIONS Antibacterial peptide LL-37 had stronger antibacterial effect via inhibition of activity of PagP.