Fig. 4.

The stiffening effect of cholesterol is lipid-type specific. Calculated bending moduli $k_c$ are plotted as a function of bilayer size for different bilayers of A) POPC and POPC/CHOL, and B) DOPC and DOPC/CHOL. All values were derived from the analysis of MD trajectories of curved bilayers, by deriving the values of $k_t/k_t$ for each composition from fitting $n_{\parallel }/N_{\parallel }$ against Eq. 3, and then using those values to fit the computed PMFs against Eq. 2 to derive $k_c$ and $k_t$ simultaneously. Shaded bands indicate the estimated 95% CI of $k_c$ (Table 2), and dashed bands indicate the 95% CIs of $k_c$ from tilt fluctuations of pure lipids (27).