Table 1.

Effect of sterols in binding and pore-forming activity of sticholysin I

Lipid composition	StI-monolayer binding	SUV permeabilization	GUV permeabilization
	πc (mN m−1)a	C50% (mol:mol)b	permeabilized GUV (%)c
DOPC:eSM:Chol	55.8 ± 0.6	2715.8 ± 193.4 a	64.37 ± 9.53 x
DOPC:eSM:Erg	48.5 ± 0.8	1243.6 ± 114.9 b	57.19 ± 6.81 y
DOPC:eSM:Cln	44.8 ± 0.8	1170.9 ± 61.7 b	53.94 ± 9.41 y
DOPC:eSM	40.7 ± 0.6	238.4 ± 8.4 c	52.82 ± 5.44 y

StI, Sticholysin I, Suv, small unilamellar vesicles; Guv, giant unilamellar vesicles; for definition of lipids, see Fig. 2 caption

^aπ_c: Pressure that must be applied to avoid incorporation of StI into the monolayer. This parameter indicates the affinity of StI for the lipid monolayers and is calculated by extrapolating regression lines from plots of π (surface pressure) versus π₀ (initial surface pressure)

^bLipid/toxin molar ratio necessary to promote the release carboxyfluorescein (50%) entrapped in SUV. The parameter was calculated by fitting dose-dependence curves of permeabilization induced by StI to a Hill sigmoid (R² > 0.96) using Origin 8.0, Microcal Inc. (Studio City, CA). Mean ± standard deviation from two independent experiments are shown. Statistical analysis was performed with one-way analysis of variance with Tukey as a post hoc test. Values in row followed by different lowercase letters are independent groups with significant differences among them (p < 0.05)

^cPercentage of permeabilized vesicles 30 min after the addition of StI. Values in row followed by different lowercase letters are independent groups with significant differences among them (p < 0.05). Between 1000 and 1800 vesicles were analyzed for each composition