Assessment of antimicrobial potency, biological function, and molecular docking of the synthetic peptide IL-20 against the major aquaculture pathogen Vibrio anguillarum.

Aquaculture is vital for global food security, but intensified practices and climate change have increased disease outbreaks, underscoring the urgent need for sustainable systems and innovative disease control strategies. The IL-20 peptide, a 20-residue antimicrobial peptide (AMP), was rationally designed to possess amphipathicity, cationicity, and high hydrophobicity for enhanced antibacterial activity. Synthesized via solid-phase Fmoc chemistry and C-terminal amidation, IL-20 achieved >96% purity. Physicochemical and structural properties were predicted using PepCalc, PEP-FOLD3, RAMPAGE, and HeliQuest, confirming its helical, amphipathic structure with a +10 net charge. In silico analysis using CAMPR3, APD3, and iAMPprep predicted strong antimicrobial potential. Molecular docking via HDOCK demonstrated strong binding of IL-20 to two Vibrio anguillarum proteins, TDH-related hemolysin and Aspartate β-semialdehyde dehydrogenase with high docking scores and multiple hydrogen/hydrophobic interactions. IL-20 showed effective antimicrobial activity with a consistent MIC of 4 μg mL-1 against V. anguillarum isolates. Stability assays revealed retained activity at varied temperatures and partial protease resistance. Hemolysis and MTT assays confirmed low cytotoxicity and minimal hemolytic effect. IL-20 also bound bacterial DNA and significantly inhibited biofilm formation. Time-kill kinetics revealed rapid bactericidal action within hours. IL-20 showed strong, stable, and safe antimicrobial activity against V. anguillarum. Overall, these findings highlight IL-20 as a promising, safe, and stable antimicrobial peptide with significant potential for development as a sustainable therapeutic agent to control Vibrio anguillarum infections in aquaculture systems.