Figure 6.

Cyclotide-induced membrane permeabilization assayed using liposomes made from an E. coli polar lipid extract, quantified by the release of carboxyfluorescein at 45 min of cyclotide incubation. Each marker represents the mean leakage in Tris buffer, pH 7.4, with standard deviations from three experiments done at individual peptide concentrations, i.e., with no cumulative additions. The gere cyclotides exhibit typical cyclotide membrane-disrupting activity profiles with the cyO2-like gere 1 being the most potent, as highlighted by the indicated EC₅₀ values. Previous liposome leakage studies on cyclotides report an EC₅₀ of 0.091 μM for neutral cyclotides compared to 0.094 μM for kB7 in the current study and an EC₅₀ of 0.076 μM for cyO2 compared to 0.070 μM for gere 1 in the current study.⁴³