[gmx-developers] gromacs can't recognize residue name with four letters in some cases

[X.Periole]

> In my pdb file, some residues' names have four letters. 
>When I use
> pdb2gmx, it works fine. The output gro file shows those 
>residues (with
> four letters). When I use editconf -f *gro -o *pdb, 
>gromacs can't
> recognize those residues with four letters. All 
>residues' names in the
> output pdb file have only three letters. For those 
>residues whose name
> have four letters, the last letter has been truncated. 
>Please check it.

Why do they have four letters names ? Are they 
unconventional
residues ? If no you should be able to change their name
via a script or by hand with a text editor. In the case of
unconventional residues you should check weather they are
defined in the topology ffXXX.rtp and modify the names.

XAvier