[gmx-users] ionomer topolgy

[Justin Lemkul]

On 9/30/13 12:50 PM, Ehsan Sadeghi wrote:
> Thanks Justin,
>
> I modified the pdb file, but it cannot recognize my residue LIG. Here is the error:
>
> Opening force field file /usr/local/gromacs/share/gromacs/top/gromos53a6.ff/aminoacids.r2b
> Reading nafion5.pdb...
> Read 46 atoms
> Analyzing pdb file
> Splitting chemical chains based on TER records or chain id changing.
> There are 1 chains and 0 blocks of water and 2 residues with 46 atoms
>
>    chain  #res #atoms
>    1 ' '     2     46
>
> All occupancies are one
> Opening force field file /usr/local/gromacs/share/gromacs/top/gromos53a6.ff/atomtypes.atp
> Atomtype 1
> Reading residue database... (gromos53a6)
> Opening force field file /usr/local/gromacs/share/gromacs/top/gromos53a6.ff/aminoacids.rtp
> Using default: not generating all possible dihedrals
> Using default: excluding 3 bonded neighbors
> Using default: generating 1,4 H--H interactions
> Using default: removing proper dihedrals found on the same bond as a proper dihedral
> Residue 108
> Sorting it all out...
> Opening force field file /usr/local/gromacs/share/gromacs/top/gromos53a6.ff/aminoacids.hdb
> Opening force field file /usr/local/gromacs/share/gromacs/top/gromos53a6.ff/aminoacids.n.tdb
> Opening force field file /usr/local/gromacs/share/gromacs/top/gromos53a6.ff/aminoacids.c.tdb
>
> Back Off! I just backed up topol.top to ./#topol.top.41#
> Processing chain 1 (46 atoms, 2 residues)
> Warning: Starting residue LIG1 in chain not identified as Protein/RNA/DNA.
> Warning: Starting residue SCH2 in chain not identified as Protein/RNA/DNA.
> Problem with chain definition, or missing terminal residues.
> This chain does not appear to contain a recognized chain molecule.
> If this is incorrect, you can edit residuetypes.dat to modify the behavior.
> 8 out of 8 lines of specbond.dat converted successfully
>
> -------------------------------------------------------
> Program pdb2gmx, VERSION 4.6.3
> Source code file: /home/ehssad/Downloads/Gromacs/gromacs-4.6.3/src/kernel/resall.c, line: 642
>
> Fatal error:
> Residue 'LIG' not found in residue topology database
> For more information and tips for troubleshooting, please check the GROMACS
> website at http://www.gromacs.org/Documentation/Errors
> -------------------------------------------------------
>

You have introduced the new .rtp entry in the correct file, right?  That is, you 
have modified /usr/local/gromacs/share/gromacs/top/gromos53a6.ff/aminoacids.rtp?

-Justin

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

Justin A. Lemkul, Ph.D.
Postdoctoral Fellow

Department of Pharmaceutical Sciences
School of Pharmacy
Health Sciences Facility II, Room 601
University of Maryland, Baltimore
20 Penn St.
Baltimore, MD 21201

jalemkul at outerbanks.umaryland.edu | (410) 706-7441

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