HP(2-9)-magainin 2(1-12), a synthetic hybrid peptide, exerts its antifungal effect on Candida albicans by damaging the plasma membrane

In our previous study, HP(2-9)-MA(1-12), HP-MA for short, a hybrid peptide incorporating residues 2-9 of Helicobacter pylori ribosomal protein L1 (HP) and residues 1-12 of magainin 2 (MA) was shown to have strong antibacterial activity. In this study the antifungal activity of HP-MA was evaluated using various fungi, and it was shown that the activity was increased when compared with the parent peptides. In order to investigate the fungicidal mechanism(s) of HP-MA its action against fungal cell membranes was examined by the potassium-release test, which showed that HP-MA caused an increase in the amount of K⁺ released from the cells. Furthermore, HP-MA induced significant morphological changes. These facts suggested that the fungicidal effect of HP-MA involves damaging the fungal cell membranes. CD investigators suggested that the α-helical structure of these peptides plays an important role in their antibiotic effect, but that α-helicity is less directly correlated with the enhanced antibiotic activity of the hybrid.