[gmx-users] PEG from ATB: No residues in chain

[Schirra, Simone]

Dear Gromacs users,

I'm totally new to GROMACS and I want to simulate a PEG chain in different environment. I found various PEG topologies on the ATB website and tried to use them combined with the force field provided on the website. However, I always get a warning like this:

"Warning: No residues in chain starting at YAHE identified as Protein/RNA/DNA.
This makes it impossible to link them into a molecule, which could either be
correct or a catastrophic error. Please check your structure, and add all
necessary residue names to residuetypes.dat if this was not correct."

I have tried different topologies, the residues are always named differently but they are never defined, although I use the force field that ATB specifies for this.
Also in other databases I could only find PEG with other residues, but not somewhere defined. Since it is a well known polymer, I guess that it's well defined somewhere and I just need to know the correct name for a r2b file or something like that...
I would be very grateful if someone could help me with this!

Simone