In silico molecular design of narrow-spectrum antimicrobial peptide XMK-8 and analysis of factors influencing its antibacterial activity.

This study aimed to obtain a narrow-spectrum antimicrobial peptide. A peptide XMK-8 was designed based on the amino acid sequence of goose MyHC1 protein from positions 1919 to 1936 (some parameters do not meet the requirements of antimicrobial peptides through bioinformatics analysis) using bioinformatics tools and amino acid substitution method. The minimum inhibitory concentration was determined using liquid double dilution method, the hemolysis rate was determined using dilution method, and the effects of temperature, acid-base, enzyme, and salt ions on its antimicrobial activity were evaluated using liquid double dilution method. The results showed that the designed peptide was a cationic hydrophilic peptide with high amphiphilicity and low hemolytic activity on mouse red blood cells. It had no antimicrobial activity against Escherichia coli, Salmonella, Staphylococcus aureus, and Aeromonas hydrophila. The minimum inhibitory concentration against Pasteurella multocida was 250 μg mL-1, and the minimum inhibitory concentration against Haemophilus parasuis was 1.00 mg mL-1. The antimicrobial activity of the narrow-spectrum antimicrobial peptide XMK-8 can still be detected after treatment with temperature (0.00 - 100 ˚C), salt ions (sodium ions and potassium ions; 50.00 - 200 mmol L-1), pH (4.00 - 10.00), and protease K (20.00 - 100 μg mL-1). Antimicrobial peptide XMK-8 was expected to become a new alternative to antibiotics and would have good application prospects in the prevention and treatment of P. multocida and H. parasuis infections.