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

Mark Abraham mark.abraham at anu.edu.au
Mon Sep 20 23:54:26 CEST 2010



----- Original Message -----
From: "Justin A. Lemkul" <jalemkul at vt.edu>
Date: Tuesday, September 21, 2010 6:30
Subject: [gmx-users] Problem with pdb2gmx and a new residue
To: Gromacs Users' List <gmx-users at gromacs.org>

> 
> 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

I think you need to define CRO as Protein in residuetypes.dat so that the pdb2gmx mechanism can deduce that it should form a C-terminal peptide link in the absence of an end-of-chain marker.

Similarly, I have a modified peptide in what's become my "system for generating pdb2gmx bugzilla reports", and with 4.5.1 and git head, if I omit the residuetypes.dat definition I see

Identified residue ALA1 as a starting terminus.
Warning: Residue KCX193 in chain has different type (Other) from starting residue ALA1 (Protein).
Warning: Residue ASP194 in chain has different type (Protein) from starting residue ALA1 (Protein).
Warning: Residue ASP195 in chain has different type (Protein) from starting residue ALA1 (Protein).
Warning: Residue GLU196 in chain has different type (Protein) from starting residue ALA1 (Protein).
Warning: Residue ASN197 in chain has different type (Protein) from starting residue ALA1 (Protein).
More than 5 unidentified residues at end of chain - disabling further warnings.
Identified residue THR192 as a ending terminus.
<snip>
-------------------------------------------------------
Program pdb2gmx_master, VERSION 4.5.1-20100916-6d51340
Source code file: ../../../src/kernel/pdb2gmx.c, line: 655

Fatal error:
Atom OXT in residue VAL 467 was not found in rtp entry VAL with 16 atoms
while sorting atoms.
.
For more information and tips for troubleshooting, please check the GROMACS
website at http://www.gromacs.org/Documentation/Errors
-------------------------------------------------------

This is a bit different, inasmuch as I see the error on the final residue of the first chain, rather then on the modified residue, as you do. However pdb2gmx should cope better with this case - clearly it's confused in the above messages about non-matching types.

We should probably file a bugzilla, even if this fixes your symptoms.

Mark
 
> 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
> 
> ========================================
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