[gmx-users] Atom O in residue was not found in rtp entry

[Sadaf Rani]

Dear Gromacs users
I have a ligand in my protein for which I make rtp file and included this
in my local copy for force field as mentioned in gromacs manual. Also, I
added atom types in ffnonbonded.itp and atomtypes.atp atomtypes.atp added
residue under protein in residuetypes.dat
But I am getting the following error:-


Splitting chemical chains based on TER records or chain id changing.
WARNING: Chain identifier 'A' is used in two non-sequential blocks.
They will be treated as separate chains unless you reorder your file.
There are 2 chains and 0 blocks of water and 490 residues with 7921 atoms

  chain  #res #atoms
  1 'A'   489   7894
  2 'A'     1     27

All occupancies are one
Opening force field file ./amber99sb-ildn.ff/atomtypes.atp
Atomtype 86
Invalid format:


------------------------------------------------------
Program:     gmx pdb2gmx, version 2019.4
Source file: src/gromacs/gmxpreprocess/pdb2gmx.cpp (line 745)

Fatal error:
Atom O in residue G6P 516 was not found in rtp entry G6P with 27 atoms
while sorting atoms.


Could you please suggest me what wrong I am doing in rtp file

Thank you in advance

Sadaf