| Abstract |
In a previous study, we reported an antibacterial peptide derived from Crocodylus siamensis hemoglobin hydrolysate, named QL17 (QAIIHNEKVQAHGKKVL); however this peptide has a narrow spectrum of activity. To improve the antimicrobial activity of the peptide, it was used as the template to design novel effective peptides. The helical wheel diagram was used to monitor and evaluate hydrophobicity and hydrophilicity after the positional change and substitution of certain amino acids. Lysine (K) and arginine (R) were appropriately selected to extend the hydrophilicity, whereas hydrophobic residues such as leucine (L), isoleucine (I) or tryptophan (W) were used to increase the hydrophobicity. As appropriate, two novel peptides were synthesized and named as IL-K (IKHWKKVWKHWKKKL) and IL-R (IRHWRRVWRHWRRRL), which had the same hydrophobicity and net charge at 40% and +7, respectively. Evaluation of the antimicrobial activity by broth microdilution assay revealed that IL-K had a slightly higher inhibition activity than IL-R at concentrations of 12.5, 25, 50 and 100 µg/ml. Both peptides had approximately 2-fold percentage inhibition higher than penicillin and as the QL17 parental peptide against Klebsiella pneumoniae and Staphylococcus aureus. Our findings suggest that the novel designed peptides are promising to be new antibacterial agents for further development and for use as antibiotics. |
Publication
Journal Publication
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