No such moleculetype UREA

GROMACS version: 5.1.5
GROMACS modification: No
Here post your question : How to fix the error of no such moleculetype UREA.

Hi everyone,
I am trying to set up a system of GB1 protein in a solvent box containing urea and water and for this I followed the mixed solvent manual of GROMACS. I have completed upto the adding urea and water molecules part successfully but when I am running the adding ions part of the simulation after modifying the topology file by adding the urea.itp file and the molecules directive, the following error pops up:

Fatal error:
No such moleculetype UREA

The modifications in the topology file:

; Include water topology
#include “amber99sb-ildn.ff/spce.itp”

; Position restraint for each water oxygen
[ position_restraints ]
; i funct fcx fcy fcz
1 1 1000 1000 1000

; Include topology for ions
#include “amber99sb-ildn.ff/ions.itp”

:Include topology for urea
#include “amber99sb-ildn.ff/urea.itp”

[ system ]
; Name

[ molecules ]
; Compound #mols
Protein_chain_A 1
Protein_chain_B 1
UREA 825
SOL 8746

In the gro file the molecule name for urea is also written as UREA.

Please help me how to fix this error.

Thanks and regards,


In directive [molecules] UREA is before SOL
You can include urea.itp before spce.itp in the topology.
Kind regards

OK, thanks.