[gmx-users] Fatal error: In the chosen force field there is no residue type for 'GLN' as a starting terminus

[Atila Petrosian]

Hi all.

After using amber03 force field for protein-ligand simulation (pdb2gmx), I
encountered with following error:

Fatal error:
In the chosen force field there is no residue type for 'GLN' as a starting
terminus.

Ligand in my system is a single residue (GLN). There are [GLN], [NGLN] and
[CGLN] in rtp file of amber03 force field. Should this single residue be as
both of [NGLN] and [CGLN]?

How to fix this error?

Any help will highly appreciated.