Antibacterial activity and mechanism of the Lithobates catesbeiana-derived novel peptide RCVI2 against Bacillus cereus.

Bacillus cereus (B. cereus) is a common foodborne pathogen, and its contamination of food products poses a substantial risk to public health and food safety. This study identified the novel antimicrobial peptide RCVI2 (LSVIASDPNYRR) from the enzymatic hydrolysate of Lithobates catesbeiana (L. catesbeiana) skin and systematically evaluated its antibacterial activity and mechanism against B. cereus. RCVI2 exhibited significant bactericidal activity against B. cereus, with a minimum bactericidal concentration of 125 μg/mL, capable of achieving complete sterilization within 3 h. Experimental studies and molecular dynamics (MD) simulations demonstrated that RCVI2 can increase cell membrane permeability and compromise integrity, and simultaneously induce excessive accumulation of intracellular reactive oxygen species, causing oxidative stress damage. RCVI2 can interact with bacterial DNA. Molecular docking results revealed that it can securely bind to DNA base pairs through non-covalent embedding, establishing a structural basis for its antibacterial mechanism of targeting nucleic acids. Additionally, the hemolysis rate of RCVI2 on sheep red blood cells at higher concentrations was <5%, demonstrating good blood compatibility, and effectively inhibiting B. cereus growth in rice paste. In conclusion, this study revealed the mechanism by which an antimicrobial peptide derived from L. catesbeiana skin collagen inhibits B. cereus through multi-target synergistic action, thereby offering theoretical support for its potential application as a novel antimicrobial agent in food safety.