A potential food biopreservative, CecXJ-37N, non-covalently intercalates into the nucleotides of bacterial genomic DNA beyond membrane attack

作者：Liu, Dongliang; Liu, Jun; Li, Jinyao; Xia, Lijie; Yang, Jianhua; Sun, Surong; Ma, Ji; Zhang, Fuchun^*

来源：Food Chemistry, 2017, 217: 576-584.

DOI：10.1016/j.foodchem.2016.09.033

• Antimicrobial peptide
• Food preservative
• Food-borne pathogen
• Amide modification
• Cell membrane penetration
• DNA intercalation

The antibacterial activities and mechanism of an amide-modified peptide CecXJ-37N were investigated in this study. CecXJ-37N showed small MICs (0.25-7.8 mu M) against eight harmful strains common in food industry. The alpha-helix proportion of CecXJ-37N increased by 11-fold in prokaryotic membrane comparable environments; cytotoxicity studies demonstrated the MHC was significantly higher than that of non-amidated isoform. Moreover, CecXJ-37N possessed stronger capacities to resist trypsin and pepsin hydrolysis within two hours. Flow cytometry and scanning electron microscopy demonstrated that CecXJ-37N induced pore-formation, morphological changes, and lysed E. coli cells. Fluorescence microscopy indicated that CecXJ-37N penetrated E. coli membrane and accumulated in cytoplasm. Further ultraviolet-visible spectroscopy suggested that CecXJ-37N changed the action mode of parental peptide interacting with bacterial genome from outside binding to a tightly non-covalent intercalation into nucleotides. Overall, this study suggested that amide-modification enhanced antimicrobial activity and reduced the cytotoxicity, thus could be potential strategies for developing novel food preservatives.

• 出版日期2017-2-15
• 单位新疆大学; 666