Novel antimicrobial peptides against Listeria monocytogenes: Isolation and structural characterization from Bacillus amyloliquefaciens 906.

In this study, three novel antimicrobial peptides (AMPs) were isolated and purified from the fermentation supernatant of B. amyloliquefaciens, and their amino acid sequences were identified by LC-MS/MS as LLLLKKPLLL, LLLPKK, and LLLSKKLL, respectively. Among them, AMP hz-01 demonstrated the highest inhibitory effects on L. monocytogenes, with a MIC of 0.12 mg/mL and MBC of 0.98 mg/mL. Its antibacterial mechanism involves disrupting cell membrane integrity, thereby causing cell death. Molecular docking and molecular dynamics simulations suggested that AMP hz-01 may interact with β-ketoacyl-acyl carrier protein synthase III through hydrogen bonding and may associate with the membrane phospholipid bilayer, supporting a proposed dual mechanism of charge-driven membrane targeting and hydrophobicity-induced membrane perturbation. These findings provide a theoretical foundation for the development of AMPs as promising, natural, and effective agents for controlling pathogenic bacteria.