Fungicidal activity of a phospholipase-A2-derived synthetic peptide variant against Candida albicans

pEM-2, a 13-mer synthetic peptide variant derived from myotoxin II, a phospholipase A(2) homologue present in Bothrops asper snake venom, has shown potent bactericidal activity in previous studies due to the combination of cationic and hydrophobic amino acids, including three tryptophan-substituted residues in its sequence. This study reports that pEM-2 also exerts potent fungicidal activity against a variety of clinically relevant Candida species, killing 100% of yeasts at concentrations near 10 mg/l (5 microM), as indicated by plate counting assays. Thus, this peptide displays a broad-spectrum antimicrobial activity, in the absence of hemolytic activity. The fungicidal action of pEM-2 against Candida can be partially inhibited by increasing concentrations of extracellular divalent cations (Ca(+2) or Mg(+2)), in agreement with its proposed membrane-permeabilizing mechanism of action.