Comparison of PEG600 free energy difference between DPPS and DPPC obtained for a single PEG600 molecule and a 10% PEG solution. In single PEG simulations (panels A–D) the distance in the horizontal axis corresponds to the distance from the PEG mass center to the averagez-position of the lipid charge. In 10% PEG simulations (panels C and D), the PEG mass center is replaced by the center of the bin used to average the PEG mass fraction.
