Cytolytic and Antibacterial Activity of Synthetic Peptides Derived from Amoebapore, the Pore-Forming Peptide of Entamoeba histolytica

The pore-forming peptide amoebapore is considered part of the cytolytic armament of pathogenic Entamoeba histolytica. Amoebapore is composed of 77 amino acid residues arranged in four α-helical domains. For structure-function analysis, synthetic peptides were constructed corresponding to these four domains: H1 (residues 1-22), H2 (25-39), H3 (40-64), and H4 (67-77). The peptides H1 and H3, representing two highly amphipathic α-helical regions of amoebapore, possessed pore-forming activity. Peptide H3 displayed cytolytic and antibacterial functions similar to those of natural amoebapore. The most potent antibacterial activity and the broadest activity spectrum were expressed by H1-Mel, a hybrid molecule composed of the N-terminal α-helix of amoebapore and the C-terminal hexapeptide of melittin from the venom of Apis mellifera.