[gmx-users] Problem in adding *.itp for 2 different ligands in topol .top

[Parshvika Sharma]

Dear gromacs users,

I want to run a protein ligand MD in Gromacs 4.6 using CHARMM forcefield.
My system consists of 2 non-covalently bound ligands (FAD and NADPH) in the
active site. I generated the topology files (*.itp) of ligands using
SWISSPARAM. Before running the energy minimization, I added the *.itp file
for both ligands in topol.top file as mentioned in the gromacs tutorial.

#include "charmm27.ff/forcefield.itp"
#include "FAD.itp"
#include "NDP.itp"

But while running GROMPP I am getting this error,

Syntax error - File NDP.itp, line 7
Last line read:
'[ atomtypes ] '
Invalid order for directive atomtypes

It just accepts the first *.itp mentioned in the topol.top, be it FAD.itp
or NDP.itp and shows this error for the file mentioned next.

I would like to know the correct way to mention *.itp  in topol.top, if we
have more than 1 ligand.


Thank you