[gmx-users] help with "interaction of type atom in the topology database, but an atom of that name was not found in residue" error

Justin Lemkul jalemkul at vt.edu
Fri Aug 31 03:29:42 CEST 2012



On 8/30/12 9:23 PM, Katrina Lexa wrote:
> Hello Gromacs Users:
>
>     I apologize for asking a question that has come up several times in the
>     forum, but I have read the answers to those posts and I am not still
>     unable to fix the error based on the suggestions in the previous emails.
>     It is completely possible that I am just not seeing the obvious, so I apologize,
>     but I would welcome any advice. I just have a methylated glycine that I would like to use (SAR) within a
>     peptide with the AMBER force field, but when I try to build the cyclic
>     compound it writes out:
>
>       Opening force field file ./amber99sb_lipid.ff/atomtypes.atp
>     Atomtype 1
>     Reading residue database... (amber99sb_lipid)
>     Opening force field file ./amber99sb_lipid.ff/aminoacids.rtp
>     Residue 100
>     Sorting it all out...
>     Opening force field file ./amber99sb_lipid.ff/aminoacids.hdb
>     Back Off! I just backed up topol.top to ./#topol.top.59#
>     Processing chain 1 'A' (85 atoms, 11 residues)
>     Identified residue ALA1 as a starting terminus.
>     Identified residue ALA11 as a ending terminus.
>     9 out of 9 lines of specbond.dat converted successfully
>     Opening force field file ./amber99sb_lipid.ff/aminoacids.arn
>     Checking for duplicate atoms....
>    -------------------------------------------------------
>     Program pdb2gmx, VERSION 4.5.5
>     Source code file: pgutil.c, line: 91
>
>     Fatal error:
>     Atom CB is used in an interaction of type atom in the topology
>     database, but an atom of that name was not found in residue
>     number 7.
>
>     However, my residue 7 should not have a CB atom, I'm not seeing it in my
>     pdb file or the .rtp file (impropers section or otherwise). Perhaps that
>     residue is being skipped, but all of my atoms are "ATOM" rather than
>     HETATM, and I don't have any tabs messing up the fields.
>
>
> this is the SAR (residue 7) section in my .rtp file
>
>     [ SAR ]
>       [ atoms ]
>           N    N           -0.22670     1
>          CN    CT          -0.22340     2
>         HN1    H            0.10210     3
>         HN2    H            0.10210     4
>         HN3    H            0.10210     5
>          CA    CT          -0.02520     6
>         HA2    H1           0.06980     7
>         HA3    H1           0.06980     8
>           C    C            0.59730     9
>           O    O           -0.56790    10
>       [ bonds ]
>           N    CN
>           N    CA
>          CA   C
>          CA   HA2
>          CA   HA3
>          CN   HN1
>          CN   HN2
>          CN   HN3
>           C     O
>          -C     N
>       [ impropers ]
>          -C    CA     N     H
>          CA    +N     C     O
>
>
> and here is a chunk of my pdb file
>
>     MODEL        1
>     ATOM      1  N   ALA A   1      -5.608   1.167   2.062  1.00    0.00           N1+
>     ATOM      2  CA  ALA A   1      -4.930   0.579   3.183  1.00     0.00           C
>     ATOM      3  CB  ALA A   1      -5.857   0.458   4.396  1.00     0.00           C
>     ATOM      4  C   ALA A   1      -3.814   1.597   3.525  1.00     0.00           C
>     ATOM      5  O   ALA A   1      -4.063   2.822   3.391  1.00  0.00           O
>     ATOM      6  N   MLE A   2      -2.575   1.132   3.819  1.00     0.00           N
>     ATOM      7  CN  MLE A   2      -2.315  -0.257   4.265  1.00     0.00           C
>     ATOM      8  CA  MLE A   2      -1.398   2.052   3.941  1.00     0.00           C
>     ATOM      9  CB  MLE A   2      -1.091   2.218   5.462  1.00     0.00           C
>     ATOM     10  CG  MLE A   2      -2.145   2.883   6.382  1.00     0.00           C
>     ATOM     11  CD1 MLE A   2      -1.689   2.877   7.897  1.00     0.00           C
>     ATOM     12  CD2 MLE A   2      -2.626   4.302   5.946  1.00     0.00           C
>    ....
>    ATOM     45  N   ABA A   6     4.961   4.195  -6.289  1.00  0.00         N
>     ATOM     46  CA  ABA A   6     5.219   4.813  -7.615  1.00  0.00         C
>     ATOM     47  CB  ABA A   6     6.627   4.541  -8.037  1.00  0.00         C
>     ATOM     48  CG  ABA A   6     7.673   5.523  -7.418  1.00  0.00         C
>     ATOM     49  C   ABA A   6     4.374   4.037  -8.636  1.00  0.00         C
>     ATOM     50  O   ABA A   6     4.360   2.841  -8.453  1.00  0.00         O
>     ATOM     51  N   SAR A   7     3.818   4.705  -9.676  1.00  0.00         N
>     ATOM     52  CN  SAR A   7     4.087   6.071  -9.873  1.00  0.00         C
>     ATOM     53  CA  SAR A   7     2.929   3.969 -10.548  1.00  0.00         C
>     ATOM     54  C   SAR A   7     1.449   4.131 -10.258  1.00  0.00         C
>     ATOM     55  O   SAR A   7     0.975   5.236 -10.559  1.00  0.00         O
>     ATOM     56  N   MLE A   8     0.814   3.165  -9.517  1.00  0.00         N
>     ATOM     57  CN  MLE A   8     1.365   1.822  -9.318  1.00  0.00         C
>     ATOM     58  CA  MLE A   8    -0.491   3.432  -8.917  1.00  0.00         C
>     ATOM     59  CB  MLE A   8    -1.599   2.488  -9.538  1.00  0.00         C
>     ATOM     60  CG  MLE A   8    -2.739   3.173 -10.337  1.00  0.00         C
>     ATOM     61  CD1 MLE A   8    -3.758   3.767  -9.396  1.00  0.00         C
>     ATOM     62  CD2 MLE A   8    -2.404   4.282 -11.348  1.00  0.00         C
>     ATOM     63  C   MLE A   8    -0.439   3.310  -7.362  1.00  0.00         C
>     ATOM     64  O   MLE A   8     0.107   2.398  -6.778  1.00  0.00         O
>     ...
>
>     Thank you for your advice,
>

If I recall correctly, the residue number printed by pdb2gmx is actually the 
residue index (starting from zero), so the problematic residue is MLE, which 
does have CB.

-Justin

-- 
========================================

Justin A. Lemkul, Ph.D.
Research Scientist
Department of Biochemistry
Virginia Tech
Blacksburg, VA
jalemkul[at]vt.edu | (540) 231-9080
http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin

========================================



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