Fig. 5

Results of the molecular dynamics simulations. a Median of the orientation of the DP-DGTS (orange) and DPPC (blue) lipid zwitterionic headgroup vector in the fluid phase as function of the repeat distance d. 90 °C corresponds to an orientation parallel to the membrane plane. The inset represents the lipid dipole moment normal to the surface vs d, indicating that DPPC dipole density is larger than that of DP-DGTS. b Water dipole density profile versus the distance z along the bilayer normal in fluid phase for DP-DGTS (orange) and DPPC (blue) bilayers, centered here at the middle of the water layer in contrast to panels (c and d), where the bilayer is centered. c and d Simulated mass density profiles of the lipids and the water versus the distance z along the bilayer normal for (c) DP-DGTS and (d) DPPC, centered at the bilayer center of mass. Also shown are the densities of the zwitterionic functional groups of the lipid heads (e.g., phosphate, carboxyl group, trimethylammonium). In (b, c, and d), the dash lines represent the profile at low hydration and the solid lines at high hydration