You need to use the same forcefield. Since you are using ATB to generate the topology for your small molecule, then it stands to reason that you then should use ATB for the lipid molecule.
Search ATB, I'm pretty sure the various lipids will already be there, and suspect they will be some that the developers of the forcefield added themselves, rather than a user submitting. Catch ya, Dr. Dallas Warren Drug Delivery, Disposition and Dynamics Monash Institute of Pharmaceutical Sciences, Monash University 381 Royal Parade, Parkville VIC 3052 dallas.war...@monash.edu --------------------------------- When the only tool you own is a hammer, every problem begins to resemble a nail. On Mon, 2 Mar 2020 at 18:40, Atila Petrosian <atila.petros...@gmail.com> wrote: > Hi Dallas, > thanks for your answer. I saw README file in gromos54a7_atb.ff from ATB > server. > > My system contains lipid molecules and small molecule. For lipid molecules, > Justine Lemkul suggested to use gromos53a6_lipid.ff. How to use both > of gromos54a7_atb.ff > and gromos53a6_lipid.ff in topology file. > > Please guide me. > > Best, > Atila > -- > Gromacs Users mailing list > > * Please search the archive at > http://www.gromacs.org/Support/Mailing_Lists/GMX-Users_List before > posting! > > * Can't post? Read http://www.gromacs.org/Support/Mailing_Lists > > * For (un)subscribe requests visit > https://maillist.sys.kth.se/mailman/listinfo/gromacs.org_gmx-users or > send a mail to gmx-users-requ...@gromacs.org. > -- Gromacs Users mailing list * Please search the archive at http://www.gromacs.org/Support/Mailing_Lists/GMX-Users_List before posting! * Can't post? Read http://www.gromacs.org/Support/Mailing_Lists * For (un)subscribe requests visit https://maillist.sys.kth.se/mailman/listinfo/gromacs.org_gmx-users or send a mail to gmx-users-requ...@gromacs.org.