Antimicrobial Peptides Containing Arginine

Tetradecapeptides (RLARLAR)2, D-(RLARLAR)2, (RLARLAA)2, and (RLGRLGR)2 were synthesized by a solid phase method using Fmoc-amino acids. The antibacterial activity of the synthesized peptides was studied against Escherichia coli cells. The minimum inhibitory concentration (MIC) was, correspondingly, 3, 1, 3, and 12 μM, which is comparable with MIC of such natural antimicrobial peptides as temporin, magainin, and dermaseptin. It was found that all of the synthesized peptides have no effect on human erythrocytes and rat thymocytes. The peptides form α-helices in 30% trifluoroethanol and in 2.5 mM SDS, which have amphipathic structure.