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 cytolyti c armament of pathogenic Entamoeba histolytica. Amoebapore is composed of 77 amino acid residues arranged in four alpha-helical domains. For structure-function analysis, synthetic peptides were constructed corr esponding to these four domains: H1 (residues 1-22), H2 (25-39), H3 (4 0-64), and H4 (67-77). The peptides Hl and H3, representing two highly amphipathic alpha-helical regions of amoebapore, possessed pore-formi ng activity. Peptide H3 displayed cytolytic and antibacterial function s similar to those of natural amoebapore. The most potent antibacteria l activity and the broadest activity spectrum were expressed by HI-Mel , a hybrid molecule composed of the N-terminal alpha-helix of amoebapo re and the C-terminal hexapeptide of melittin from the venom of Apis m ellifera.