We performed MD analysis using DS 2020 in our lab. Now reviewer has raised a question regarding the parametrization of protein-ligand complex. Normally in Gromacs or NAMD the parametrization part was done with the help of CHARMm-GUI platform. But in DS we did not need to do that (as per tutorial) so how should I response to the reviewer's query? one more question in MD, CHARMm27 or CHARMm36, which force field is preferable?