[gmx-users] How to build and simulate POPE/POPG bilayer with gromos54a7 force field

[daniel depope]

I want to simulate POPE/POPG bilayer with gromos54a7 ff (expanded with
lipids parts, as explained in Lemkul's kalp tutorial).

1. I tried CHARMM-gui website - I got bilayer in step 5, but can't finalize
because there are no gromos ff option. So I looked for pope and popg
gromos54a7 topology, but with no succes so I stacked. Any suggestions how
to proceed?

2.  Another option was to build that bilayer with packmol, but I can't find
a way to do so (I know how to build homogenuos bilayer).

3. POPE molecule from CHARMM-gui website have 125 atoms. I have some old
POPE molecule with only 52 atoms. Last one has only two hydrogen atoms. Can
anyone explain why is that a case.

Obvioiusly I missed some basics, I apologize for that, but I need
clarification to move on..

Thanks