Chemistry and Antimicrobial Potential of the Buffalo Myeloid Cathelicidin, BuMAP-34

Abstract

A putative cathelicidin antimicrobial peptide of 34 amino acid residues was deduced from buffalo myeloid gene sequences and named as Buffalo myeloid antimicrobial peptide-34 (BuMAP-34). Structure–function relationship of the custom synthesized peptide was evaluated in vitro. Highly cationic, amphipathic peptide showed a net charge of +6 and predicted hydrophobic ratio of 38 %. Phylogenetic analysis revealed an evolutionary relationship with Bovine myeloid antimicrobial peptide-34 (BMAP-34) of cattle, myeloid antimicrobial peptide-34 (MAP-34) of Goat and Sheep myeloid antimicrobial peptide-34 (SMAP-34). Peptide showed potent antimicrobial activity against a wide spectrum of microorganisms including Gram-negative and Gram-positive bacteria and fungi. Minimum inhibitory concentration (MIC) on various strains of bacteria, and fungus ranged from 1.1 to 1.5 µM except for P. multocida multocida (HS), which was >100 µM. Scanning electron microscopic (SEM) analysis of the peptide treated E. coli, S. aureus and C. albicans indicated cell lysis. Peptide also showed its ability to bind with anionic components of the cells which was confirmed by DNA binding assay. Haemolytic activity assay revealed absence of haemolysis in human RBCs at 12.5 µM and in sheep RBCs even at 100 µM concentration of the peptide. The present study suggests that the cathelicidin, BuMAP-34 has strong antimicrobial activity and could be developed as a promising broad spectrum antimicrobial agent.