[gmx-users] Issues with my PDB file

Justin A. Lemkul jalemkul at vt.edu
Thu Apr 2 22:59:55 CEST 2009



Jacob Harvey wrote:
> Justin,
> 
> Thank you for your response. I figured this was the problem actually and 
> tried renaming things a little bit but I got confused and my file still 
> didn't work. I'll try and dig that file up to show you, but what exactly 
> do I need to rename and if I want to use the OPLS-AA force field what do 
> I need to rename things to. Is it the opls_XXX atoms in the .atp file? 
> Where is it getting "residue 2" from? Is that from the atom number 2 or 
> the two columns of 2's next to the atom name (ie. C,N,H)? I'm not sure I 
> understand the structure of a pdb file. Thank you very much for your 
> response.
> 

I would suggest some tutorial material on a well-defined protein or some other 
simple system.  See the wiki for some examples about how to start without diving
head-first into a bizarre example that may not work.

Wiki: http://wiki.gromacs.org/index.php/Main_Page

PDB file format: http://www.wwpdb.org/documentation/format32/sect9.html

Note as well that pdb2gmx will only work on building block compounds (proteins, 
nucleic acids, and a limited set of cofactors, generally - this depends on the 
force field).  So if you expect pdb2gmx to be magic, expect to be disappointed.

-Justin

> Jacob
> 
> On Thu, Apr 2, 2009 at 3:13 PM, Justin A. Lemkul <jalemkul at vt.edu 
> <mailto:jalemkul at vt.edu>> wrote:
> 
> 
> 
>     Jacob Harvey wrote:
> 
>         Dear all,
> 
>         I appear to be having problems with my pdb file for gromacs. If
>         someone could help me out that would be awesome. I enter the
>         following code to run pdb2gmx:
> 
>         pdb2gmx -f test.pdb
> 
>         and then I select a force field. I have selected OPLS-AA/L
>         all-atom force field (2001 aminoacid dihedrals). Once I select
>         the force field I get the error
> 
>         "Fatal error:
>         Residue '2' not found in residue topology database"
> 
> 
>     That one's pretty self-explanatory.  You can't expect pdb2gmx to be
>     magic. Parameters have to exist in the force field .rtp file for
>     each building block you want to use.  A residue named "2" is
>     meaningless to pdb2gmx.
> 
>     -Justin
> 
>         This is what my pdb file looks like (I've just posted the first
>         10-15 lines or so). Does anyone see where I am going wrong?
>         Thank you very much in advance.
> 
>         HETATM    1  C     2     2      -4.438   3.334   2.988
>         HETATM    2  C     2     2       0.588   3.313   0.517
>         HETATM    3  C     2     2       5.476   3.310  -2.216
>         HETATM    4  H     2     2      -4.134   2.590   3.731
>         HETATM    5  H     2     2      -5.525   3.438   3.047
>         HETATM    6  H     2     2      -3.996   4.291   3.276
>         HETATM    7  H     2     2       1.480   3.111   1.117
>         HETATM    8  H     2     2      -0.266   3.349   1.200
>         HETATM    9  H     2     2       0.702   4.307   0.076
>         HETATM   10  H     2     2       6.375   3.525  -1.633
>         HETATM   11  H     2     2       4.648   3.862  -1.761
>         HETATM   12  H     2     2       5.628   3.709  -3.223
>         HETATM   13  C     2     2      -3.996   2.922   1.581
>         HETATM   14  H     2     2      -2.902   2.862   1.545
>         HETATM   15  H     2     2      -4.281   3.703   0.865
>         HETATM   16  C     2     2       0.394   2.242  -0.557
>         HETATM   17  H     2     2      -0.485   2.486  -1.167
>         .
>         .
>         .
>         .
>         .
> 
>         Jacob Harvey
> 
>         -- 
>         --
>         Jacob Harvey
> 
>         Graduate Student
> 
>         University of Massachusetts Amherst
> 
>         j.harv8 at gmail.com <mailto:j.harv8 at gmail.com>
>         <mailto:j.harv8 at gmail.com <mailto:j.harv8 at gmail.com>>
> 
> 
>         ------------------------------------------------------------------------
> 
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> 
>     -- 
>     ========================================
> 
>     Justin A. Lemkul
>     Graduate Research Assistant
>     ICTAS Doctoral Scholar
>     Department of Biochemistry
>     Virginia Tech
>     Blacksburg, VA
>     jalemkul[at]vt.edu <http://vt.edu> | (540) 231-9080
>     http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin
> 
>     ========================================
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> 
> 
> 
> 
> -- 
> --
> Jacob Harvey
> 
> Graduate Student
> 
> University of Massachusetts Amherst
> 
> j.harv8 at gmail.com <mailto:j.harv8 at gmail.com>

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

Justin A. Lemkul
Graduate Research Assistant
ICTAS Doctoral Scholar
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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