Design, synthesis, antibacterial and antitubercular activity of cationic antimicrobial peptide, ovine bactenecin5

Abstract

A series of shorter synthetic peptides analogues of ovine bactenecin 5 (OaBac5), Phe-Arg-Pro-Xaa (Xaa= Phe, Met, Tyr and Trp) are designed and synthesized. The tetra peptides synthesized are conjugated with the isonicotinic acid at the N-terminal of the tetra peptides to study the change in the biological activity. The shorter synthetic tetra peptide analogues of OaBac5 and isonicotinic acid conjugated tetra peptides are more active against Gram negative bacteria than Gram positive bacteria. For Gram negative bacteria, the overall order of antibacterial activity of the synthesized tetrapeptides is found to be Phe-Arg-Pro-Trp >Phe-Arg-Pro-Phe >Phe-Arg-Pro-Met ≥Phe-Arg-Pro-Tyr. The isonicotinic acid conjugated tetra peptides have showed reduced antibacterial activity when compared to the tetra peptides. All the peptide derivatives showed moderate antitubercular activity. None of the peptides exhibited prominent haemolytic activity.