The antibiotics that have saved millions of life through decades are losing its effectiveness for treatment of many diseases, due to rapid emergence of resistant microorganisms. In this scenario, plants can be used as resources for isolation of novel moieties like antimicrobial peptides (AMPs), which can be used or designed as drugs against multidrug-resistant. Indian subcontinent having large plant biodiversity gives an opportunity to explore for these moieties’. We isolated a novel AMP (MoCh I) from Momordica charantia (Karela) seeds having molecular weight of 3.7 kDa. This AMP had strong antimicrobial effect on Gram-positive bacteria (Bacillus licheniformis, Bacillus subtilis and Staphylococcus aureus) and showed non-hemolytic properties. MoCh I consisting of 34 amino acids (cysteine rich) was found to have sequence similarity with Trypsin inhibitor 1 of Momordica cochinchinensis. Circular Dichroism spectra indicated the presence of β-sheets and turn in the peptide structure. The in-silico analysis indicated that Putative Conserved Domain belongs to Plant Trypsin inhibitor super family. The minimum inhibitory concentration was found to be 65.2 μg/mL on B. subtilis and 87.0 μg/mL on B. licheniformis and S. aureus. The antimicrobial activity of this novel peptide might be due to the contact with lipid molecules present on bacterial surface and/or thus interacting with other targets in the cytoplasm.
Key words: Momordica charantia, Antimicrobial peptide, Plant Trypsin Inhibitor (Plant TI), Knottin, Gram Positive Bacteria
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