A potential food biopreservative, CecXJ-37N, non-covalently intercalates into the nucleotides of bacterial genomic DNA beyond membrane attack.
The antibacterial activities and mechanism of an amide-modified peptide CecXJ-37N were investigated in this study. CecXJ-37N showed small MICs (0.25-7.8μM) against eight harmful strains common in food industry. The α-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.
Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, 830046 Urumqi, China.
Dongliang
D
Liu
Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, 830046 Urumqi, China.
Jun
J
Liu
Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, 830046 Urumqi, China.
Jinyao
J
Li
Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, 830046 Urumqi, China.
Lijie
L
Xia
Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, 830046 Urumqi, China; Texas Children's Cancer Center, Department of Pediatrics, Baylor College of Medicine, Houston, 77030 TX, USA.
Jianhua
J
Yang
Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, 830046 Urumqi, China.
Surong
S
Sun
Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, 830046 Urumqi, China.
Ji
J
Ma
Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, 830046 Urumqi, China. Electronic address: zfcxju@qq.com.
Fuchun
F
Zhang
D000818:Animals; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry / Q000494:pharmacology; D002462:Cell Membrane / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004269:DNA, Bacterial / Q000737:chemistry*; D004926:Escherichia coli / Q000187:drug effects*; D005506:Food Contamination / Q000517:prevention & control; D005516:Food Microbiology; D005520:Food Preservatives / Q000737:chemistry* / Q000494:pharmacology*; D016680:Genome, Bacterial; D051379:Mice; D008826:Microbial Sensitivity Tests; D015394:Molecular Structure; D041681:NIH 3T3 Cells
D000900:Anti-Bacterial Agents; D023181:Antimicrobial Cationic Peptides; D004269:DNA, Bacterial; D005520:Food Preservatives
Amide modification; Antimicrobial peptide; Cell membrane penetration; DNA intercalation; Food preservative; Food-borne pathogen