[gmx-users] Problem with pdb2gmx and a new residue

Justin A. Lemkul jalemkul at vt.edu
Mon Sep 20 22:29:10 CEST 2010


Hi All,

I'm trying to build a topology for a chromophore-containing protein using 
Gromacs 4.5 and OPLS-AA.  The chromophore is incorporated into the protein's 
backbone and the parameters all come from a reputable publication, so I've done 
the following:

1. Created a new .rtp entry
2. Created an .hdb entry
3. Defined all nonbonded parameters for new atomtypes in the .atp and 
ffnonbonded.itp file
4. Defined all new bonded parameters in ffbonded.itp

The coordinate file was then input into pdb2gmx with an oplsaa.ff directory in 
the working directory.  I received the following error (identical with version 
4.5 and the most recent git with release-4-5-patches):

pdb2gmx -f struct.pdb
...
-------------------------------------------------------
Program pdb2gmx, VERSION 4.5.1-20100920-03d181e
Source code file: pdb2gmx.c, line: 655

Fatal error:
Atom OXT in residue CRO 331 was not found in rtp entry CRO with 39 atoms
while sorting atoms.
.
For more information and tips for troubleshooting, please check the GROMACS
website at http://www.gromacs.org/Documentation/Errors
-------------------------------------------------------

The CRO residue is my chromophore.  I'm wondering why pdb2gmx is finding an OXT 
atom in the following coordinates:

...
ATOM   2528  N   LEU A 330     -13.640  10.888 -25.907  1.00  0.00
ATOM   2529  CA  LEU A 330     -12.513  11.013 -26.852  1.00  0.00
ATOM   2530  C   LEU A 330     -11.281  10.183 -26.416  1.00  0.00
ATOM   2531  O   LEU A 330     -10.625   9.588 -27.277  1.00  0.00
ATOM   2532  CB  LEU A 330     -12.159  12.493 -27.066  1.00  0.00
ATOM   2533  CG  LEU A 330     -13.206  13.415 -27.691  1.00  0.00
ATOM   2534  CD1 LEU A 330     -12.913  14.905 -27.393  1.00  0.00
ATOM   2535  CD2 LEU A 330     -13.400  13.160 -29.207  1.00  0.00
ATOM   2536  N   CRO A 331     -10.669   9.142 -25.611  1.00  0.00
ATOM   2537  CE  CRO A 331      -7.407  12.564 -27.240  1.00  0.00
ATOM   2538  SD  CRO A 331      -8.035  12.603 -25.595  1.00  0.00
ATOM   2539  CG1 CRO A 331      -8.731  10.996 -25.519  1.00  0.00
ATOM   2540  CB1 CRO A 331      -9.618  10.846 -24.279  1.00  0.00
ATOM   2541  CA1 CRO A 331     -10.227   9.470 -24.406  1.00  0.00
ATOM   2542  C1  CRO A 331     -10.304   8.516 -23.260  1.00  0.00
ATOM   2543  N2  CRO A 331      -9.873   8.765 -21.981  1.00  0.00
ATOM   2544  OH  CRO A 331      -8.594  11.111 -15.969  1.00  0.00
ATOM   2545  CD2 CRO A 331      -9.219   9.756 -19.205  1.00  0.00
ATOM   2546  CE2 CRO A 331      -8.888  10.677 -18.207  1.00  0.00
ATOM   2547  CZ  CRO A 331      -8.898  10.286 -16.863  1.00  0.00
ATOM   2548  CE1 CRO A 331      -9.219   8.975 -16.518  1.00  0.00
ATOM   2549  CD1 CRO A 331      -9.549   8.056 -17.509  1.00  0.00
ATOM   2550  CG2 CRO A 331      -9.557   8.447 -18.848  1.00  0.00
ATOM   2551  CB2 CRO A 331      -9.880   7.417 -19.857  1.00  0.00
ATOM   2552  CA2 CRO A 331     -10.149   7.645 -21.293  1.00  0.00
ATOM   2553  C2  CRO A 331     -10.726   6.753 -22.143  1.00  0.00
ATOM   2554  O2  CRO A 331     -11.108   5.574 -21.819  1.00  0.00
ATOM   2555  N3  CRO A 331     -10.810   7.255 -23.355  1.00  0.00
ATOM   2556  CA3 CRO A 331     -11.435   6.545 -24.488  1.00  0.00
ATOM   2557  C   CRO A 331     -10.492   6.111 -25.580  1.00  0.00
ATOM   2558  O   CRO A 331     -10.993   5.596 -26.570  1.00  0.00
ATOM   2559  N   VAL A 332      -9.265   5.813 -25.096  1.00  0.00
ATOM   2560  CA  VAL A 332      -8.235   4.899 -25.607  1.00  0.00
ATOM   2561  C   VAL A 332      -7.512   4.308 -24.397  1.00  0.00
ATOM   2562  O   VAL A 332      -6.351   4.567 -24.155  1.00  0.00
ATOM   2563  CB  VAL A 332      -7.312   5.633 -26.627  1.00  0.00
ATOM   2564  CG1 VAL A 332      -8.127   5.980 -27.896  1.00  0.00
ATOM   2565  CG2 VAL A 332      -6.687   6.887 -26.051  1.00  0.00
...

Any ideas on what's going on?  I can upload a bugzilla if necessary, I just 
thought I'd report here first since I'm not sure if I'm doing something wrong 
with respect to the many new pdb2gmx features.

-Justin

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

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

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



More information about the gromacs.org_gmx-users mailing list