Fig. 5.

The elastic and viscous properties are linked to the membrane structure and scale with the area per lipid, A_L. Bending modulus (A), compressibility modulus (B), and viscosity (C) vs. A_L for all lipid compositions measured at various temperatures in the lipid fluid phase. The points are the measured data, and the lines are the expected scaling for the respective properties indicated in the legend where c and d are constants. See text for details. Crosses in A correspond to bending modulus values from simulations by Doktorova et al. of $(+)$ pure phosphatidylcholine lipid membranes and $(\times )$ mixtures of zwitterionic monounsaturated phosphatidylcholine (PC) and phosphatidylethanolamine (PE) lipids with charged phosphatidylserine (PS) and phosphatidylglycerol (PG) lipids (46). Values of A_L and κ were taken from tables 1 and 2 in the reference, respectively. The mixtures include 1-palmitoyl-2-oleoyl phosphatidylethanolamine (POPE) with 1-palmitoyl-2-oleoyl phosphatidylglycerol (POPG) (POPE/POPG 70:30) and 1-palmitoyl-2-oleoyl phosphatidylserine (POPS) (POPE/POPS 70:30) as well as mixtures of 1-palmitoyl-2-oleoyl phosphatidylcholine (POPC) with POPS (POPC/POPS 70:30) and palmitoyl sphingomyelin (PSM) (POPC/PSM 70:30). All points were weighted equally for the fits, and shaded areas represent the 95% confidence bands.