Disruption of interactions between hydrophobic residues on nonpolar faces is a key determinant in decreasing hemolysis and increasing antimicrobial activities of α-helical amphipathic peptides.

To design antimicrobial peptides with decrease pore-forming activity in eukaryotic (host) membranes, an amphipathic α-helical model peptide composed of Leu and Lys was modified to probe the balance in antimicrobial and hemolytic activities. Among analogues with broken hydrophobic interactions, L8N derivative exhibited an 8000-fold decrease in hemolytic activity and an eightfold improvement in antimicrobial activity, affording a 64 000-fold increase in therapeutic index against E. coli.