Characterization of a Novel Antimicrobial Peptide Isolated from <i>Moringa oleifera</i> Seed Protein Hydrolysates and Its Membrane Damaging Effects on <i>Staphylococcus aureus</i>

Abstract

The present study sought to identify and characterize a novel antimicrobial peptide, named MOp2 from <i>Moringa oleifera</i> seed protein hydrolysates, and elucidate its potential antimicrobial effects on <i>Staphylococcus aureus</i>. MOp2, with the amino acid sequence of His-Val-Leu-Asp-Thr-Pro-Leu-Leu (HVLDTPLL), was characterized as a hydrophobic anionic AMP of the β-sheet structure. MOp2 exhibited negligible hemolytic activity at 2.0× MIC, suggesting its inhibitory effect on the growth of <i>S. aureus</i> (MIC: 2.204 mM). It maintained more than 90% of antimicrobial activity under 5% salt and about 78% of antimicrobial activity at a high temperature of 115 °C for 30 min. Protease, especially acid protease, reduced its antimicrobial activity to different extents. Moreover, MOp2 caused irreversible membrane damage to <i>S. aureus</i> cells by increasing the membrane permeability, resulting in the release of intracellular nucleotide pools. Additionally, molecular docking revealed that MOp2 could inhibit <i>S. aureus</i> growth by interacting with dihydrofolate reductase and DNA gyrase through hydrogen bonding and hydrophobic interactions. Overall, MOp2 could be a potential novel antimicrobial agent against <i>S. aureus</i> in food processing.