Antimicrobial Activity and Mechanism of the Cottonseed Protein-derived Peptide
In the paper, antibacterial peptides were separated and identified from cottonseed protein hydrolysates and the antibacterial mechanism was further studied Firstly, by using a combined strategy of Amberlite CG-50 ion exchange chromatography and reversed-phase high-performance liquid chromatography, three peptides with antibacterial activity were purified and identified, including HHRRFSLY, KFMPT, and RRLFSDY. Interestingly, HHRRFSLY and RRLFSDY exhibited higher inhibition activity with the IC50 value of 0.26 mg/mL and 0.58 mg/mL (p<0.05), respectively. Flow cytometry results showed the antibacterial peptide damage to the integrity of the E. coli. Transmission electron microscope and scanning electron microscope results revealed the damage caused to the bacterial cell surface by the antibacterial peptides. Molecular docking studies indicated that HHRRFSLY, KFMPT, and RRLFSDY could bind to the active sites of surface protein (OmpF) through hydrogen bond and salt bridge. The results here showed that the cottonseed protein antibacterial peptide could be used as a good choice for functional foods or related drugs, and also provided a theoretical basis for the study of antibacterial mechanism.