[gmx-users] dna with charmm36

[gromacs query]

Hi All

I have simple DNA pdb which has just 5 DA residues built from NAB in AMBER.
I am trying to use pdb2gmx with charmm36-jan2014.ff downloaded from:

 http://mackerell.umaryland.edu/CHARMM_ff_params.html


pdb2gmx -f a.pdb -o gro.pdb -ff charmm36-jan2014


I have changed all names according to DA residue defined in
charmm36-jan2014.ff/merged.rtp but still I get error:

Fatal error:
atom N not found in buiding block 1DA while combining tdb and rtp