The lateral diffusion of water along the membrane surface, D ∥ , was calculated with the Einstein's equation using the -lateral option in the gmx msd program within the Gromacs software package . The code that calculates D ∥ for water from all simulations in the NMRlipids Databank is available at /scripts/calcWATERdiffusion.py, and the resulting diffusion coefficients are stored at /Data/WATERdiffusion in the repository at .