Combating Escherichia coli O157:H7 with Functionalized Chickpea-Derived Antimicrobial Peptides

Area of Science:

• Biochemistry
• Microbiology
• Drug Discovery

Background:

• Antibiotic resistance is a growing global health threat, necessitating the development of novel antibacterial agents.
• Antimicrobial peptides (AMPs) are a promising class of therapeutics, but their clinical application requires optimization.
• Chickpea-derived AMPs offer a natural scaffold for developing new antibacterial compounds.

Purpose of the Study:

• To design and characterize functionalized chickpea-derived Leg2 antimicrobial peptides (FCLAPs) with enhanced antibacterial activity.
• To evaluate the efficacy of FCLAPs against the foodborne pathogen Escherichia coli (E. coli) O157:H7.
• To elucidate the mechanism of action of potent FCLAPs against E. coli O157:H7.

Main Methods:

• Modification of a natural chickpea-derived AMP (Leg2) to create FCLAPs.
• Determination of Minimum Inhibitory Concentrations (MICs) against E. coli O157:H7.
• In vivo studies to assess FCLAP efficacy in alleviating E. coli O157:H7-induced intestinal infection.
• Multi-omics profiling, peptide-membrane interaction assays, microscopy, and mass spectrometry to characterize the antibacterial mechanism.

Main Results:

• FCLAPs KTA and KTR exhibited superior antibacterial efficacy against E. coli O157:H7 (MICs 2.5-4.7 µmol L⁻¹).
• KTA and KTR demonstrated feasibility in alleviating E. coli O157:H7-induced intestinal infection with low cytotoxicity.
• A dual-targeting mechanism was identified: initial targeting of lipopolysaccharide (LPS) for outer membrane traversal, followed by peptidoglycan (PGN) layer intercalation and synthesis inhibition.
• The FCLAPs showed insusceptibility to antimicrobial resistance.

Conclusions:

• FCLAPs, particularly KTA and KTR, represent promising antibacterial candidates against E. coli O157:H7.
• The dual-targeting mechanism involving LPS and PGN disruption offers a novel strategy to overcome resistance.
• FCLAPs possess favorable characteristics, including low cytotoxicity and resistance insusceptibility, for potential therapeutic applications.