(color online) The molecular structures of coarse-grained lipids used in this work. The ethanolamine groups of PE and serine groups of PS are represented by positively-charged beads Q and polar beads P₅, respectively. The phosphate groups and glycerol groups of all lipids are represented by negatively-charged beads Q and nonpolar beads Na, respectively. In the fatty acid tails of the lipids, the units linked with saturated bonds are represented by apolar beads C₁ and the units linked with unsaturated bonds are represented by apolar beads C . Cholesterol is mapped with five beads and three virtual sites.^{[47,48,53,54]}