[gmx-users] build membrane system from Charmm-Gui

[Xiang Ning]

Hi All, 

I am using POPC/POPG mixed membrane built by Charmm-gui. After remove ions and water from CHARMMGUI pdb and save just the membrane pdb, and use this pdb with pdb2gmx to get top file (I used charmm36), then I would like to know, how to add water and ions back to the system? I read the previous solution was to modify [molecules] in top file (add ions and waters information manually), are there any detailed explanation of how to do that? 

Thanks very much!!

Best,
Ning