Before production runs, the systems underwent 1500 steps of energy minimization and were subsequently equilibrated for a total of ~2 ns with increasing time steps (from 1 fs to 20 fs, see Table ). The production run for each system was 10 µs. During the equilibration and production runs, LINCS 185 constraints were used for ring systems and stiff bond constraints; the LINCS order and iteration were set to 12 and 2. The temperatures of lipids and solvent (NA, CL, and W beads) were independently maintained at 297 K with a time constant for coupling (τT) of 1.0 ps, using the Berendsen 187 and v-rescale 198 thermostats during the equilibration and production, respectively. The pressure was maintained at 1 bar using the Berendsen 187 barostat during equilibrations and the Parrinello-Rahman 188 barostat during the production runs. The compressibility was set to 3 × 10 -4 bar -1 . As suggested by , the cut-off distance for the short-range neighbor list was set to 1.35 nm for proper neighbor list updates. To maintain a flat bilayer , z-coordinate positional restraints were applied to the PO4 beads of the phospholipids in the upper leaflet, with a force constant of 2 kJ/mol/nm 2 .