Starting structures were constructed using the system builder and model system regeneration tools implemented in the Schrödinger software package . The SPC water model ( ) was used to solvate the systems. In addition, TIP3P (74) was used as a comparison in few systems to ensure that the water model does not significantly influence the order parameters (see Supplementary Information for details). For the dehydrated systems, excess water was removed from the starting structure of the full hydration system to attain the different hydration states. For the ion-containing systems, numbers of ions were calculated as Nc = [salt] x N w / [water], where [water]=55.5 M. The system with the strongest ion concentration (1 M) was constructed first using the system builder, and other concentrations were generated by randomly removing excess ions. Simulations were performed using Desmond in Schrödinger suite's package version 2019-4 . Default settings for membrane systems were used with 2 fs time step and saving data every 10 ps; systems were relaxed before simulations with the default membrane relaxation protocol of Desmond.