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Hello, I am working with circular DNA. I have modified the names of the first and last residues. However, when using pdb2gmx, I encountered this error.
Processing chain 1 (2829 atoms, 89 residues)
Identified residue DG1 as a starting terminus.
Identified residue DT89 as a ending terminus.
8 out of 8 lines of specbond.dat converted successfully
Opening force field file ./amber99sb-ildn-phi-bsc0-cufix.ff/aminoacids.arn
Opening force field file ./amber99sb-ildn-phi-bsc0-cufix.ff/dna.arn
Opening force field file ./amber99sb-ildn-phi-bsc0-cufix.ff/rna.arn
Checking for duplicate atoms…
Generating any missing hydrogen atoms and/or adding termini.
Now there are 89 residues with 2829 atoms
Chain time…
Making bonds…
Number of bonds was 3047, now 3047
Generating angles, dihedrals and pairs…
Before cleaning: 7413 pairs
Before cleaning: 8058 dihedrals
Making cmap torsions…
There are 8058 dihedrals, 519 impropers, 5547 angles
7146 pairs, 3047 bonds and 0 virtual sites
Total mass 27414.258 a.m.u.
Total charge -89.000 e
Writing topology
Back Off! I just backed up posre_DNA.itp to ./#posre_DNA.itp.1#
Processing chain 2 (2820 atoms, 89 residues)
Identified residue DA90 as a starting terminus.
Identified residue DC178 as a ending terminus.
8 out of 8 lines of specbond.dat converted successfully
Opening force field file ./amber99sb-ildn-phi-bsc0-cufix.ff/aminoacids.arn
Opening force field file ./amber99sb-ildn-phi-bsc0-cufix.ff/dna.arn
Opening force field file ./amber99sb-ildn-phi-bsc0-cufix.ff/rna.arn
Program: gmx pdb2gmx, version 2023.1-conda_forge
Source file: src/gromacs/gmxpreprocess/pdb2gmx.cpp (line 870)
Fatal error:
Atom P in residue DA 90 was not found in rtp entry DA5 with 30 atoms
while sorting atoms.
The first chain spans residues 1-89, and the second chain spans residues 90-178. To provide context, I used the first residue from the first chain and the last residue from the second chain as references.
ATOM 1 P DG 1 -0.022 9.276 -1.766 1.00 0.00 P
ATOM 2 O1P DG 1 -0.713 10.636 -1.583 1.00 0.00 O
ATOM 2827 1H2’ DT 89 2.237 6.683 -2.592 1.00 0.00 H
ATOM 2828 2H2’ DT 89 0.642 6.884 -2.040 1.00 0.00 H
ATOM 2829 O3’ DT 89 0.160 9.167 -3.501 1.00 0.00 O
TER
ATOM 2830 P DA 90 -4.696 -7.723 -1.995 1.00 0.00 P
ATOM 2831 O5’ DA 90 -5.115 -6.424 -2.658 1.00 0.00 O
ATOM 2832 C5’ DA 90 -5.883 -5.639 -1.744 1.00 0.00 C
ATOM 2833 1H5’ DA 90 -5.241 -5.272 -0.934 1.00 0.00 H
ATOM 5645 H3’ DC 178 -2.550 -8.595 -0.261 1.00 0.00 H
ATOM 5646 C2’ DC 178 -2.398 -6.516 -0.897 1.00 0.00 C
ATOM 5647 1H2’ DC 178 -1.397 -6.801 -1.223 1.00 0.00 H
ATOM 5648 2H2’ DC 178 -2.958 -6.257 -1.772 1.00 0.00 H
ATOM 5649 O3’ DC 178 -4.429 -7.771 -0.343 1.00 0.00 O
TER
END
I suspect the issue might be related to the presence of ‘END’ and ‘TER’ in the PDB file. It seems challenging to distinguish whether the first and last residues are properly bonded.
Residue 1 is bonded to 89, and residue 90 is bound to 178. How should pdb2gmx understand that it is a closed DNA structure? Additionally, does it not consider residue 1 as the starting terminus?
Any guidance on resolving this issue would be appreciated.