[gmx-users] Fatal error:Chain identifier

Justin A. Lemkul jalemkul at vt.edu
Wed Dec 29 19:07:24 CET 2010



ahmet yıldırım wrote:
> OK. if I do what sort change in pdb file, there is no need to create 
> .rtp file. It seems difficult to create the .rtp file.
> 

That depends on whether you need this residue, hence all of my previous 
questions.  If there is some functional significance to this residue and you 
need it for a simulation, then you'll either need to deal with the .rtp file, 
which actually is not terribly difficult, it just involves a little bit of 
reading and studying existing examples.  Otherwise, if the molecule is 
non-covalently bound to the protein, follow the tutorial I linked before, and 
pay attention to the hint I gave you before about using PRODRG, which I will 
reiterate more explicitly: the output topology from PRODRG will require manual 
modification and validation.

http://www.gromacs.org/Downloads/Related_Software/PRODRG#Tips

-Justin

> Thanks for your help
> 
> 29 Aralık 2010 19:49 tarihinde Justin A. Lemkul <jalemkul at vt.edu 
> <mailto:jalemkul at vt.edu>> yazdı:
> 
> 
> 
>     ahmet yıldırım wrote:
> 
>         You said "You do not have to make changes in pdb file".
> 
> 
>     When did I say that?
> 
> 
>         Then How will I create .rtp file.
> 
> 
>     That depends entirely upon what that residue is.  Is it a
>     constituent residue of the protein, such that its backbone is
>     incorporated in the protein structure? Is it connected via a
>     sidechain?  Or is it a ligand?  Any or all of the following might apply:
> 
>     http://www.gromacs.org/Documentation/File_Formats/.rtp_File
>     http://www.gromacs.org/Documentation/How-tos/Adding_a_Residue_to_a_Force_Field
>     http://www.gromacs.org/Documentation/File_Formats/specbond.dat
>     http://www.gromacs.org/Documentation/Tutorials#General (Drug-enzyme
>     complex, although beware the use of PRODRG)
> 
>     And, of course, the manual, which describes the contents of the .rtp
>     file more thoroughly.
> 
>     -Justin
> 
>         29 Aralık 2010 19:32 tarihinde Justin A. Lemkul <jalemkul at vt.edu
>         <mailto:jalemkul at vt.edu> <mailto:jalemkul at vt.edu
>         <mailto:jalemkul at vt.edu>>> yazdı:
> 
> 
> 
> 
>            ahmet yıldırım wrote:
> 
>                Dear Justin,
> 
>                Thanks for your reply. Where is the error?
> 
>                Pdb file:
> 
>                ATOM      1  N   ALA A   4
>                ATOM      2  CA  ALA A   4
>                ....
>                ATOM   2688  N   ALA B   4
>                ATOM   2689  CA  ALA B   4
>                ....
>                ATOM   5449  OXT GLN B 361
>                TER    5450      GLN B 361
> 
> 
>            Right here.  You're going from the end of chain B to the
>         beginning
>            of chain A, then back to B later on.  Also realize that whatever
>            "ABSG" or "BSG" is, it won't be recognized by pdb2gmx unless
>         you've
>            built a proper .rtp entry for it.
> 
>            -Justin
> 
>                HETATM 5451  OAAABSG A   1
>                HETATM 5452  OABABSG A   1
>                ....
>                HETATM 5474  OAAABSG B   2
>                HETATM 5475  OABABSG B   2
>                ....
>                HETATM 5492  O   HOH A   2
>                HETATM 5493  O   HOH A 362
>                HETATM 5494  O   HOH A 363
>                ....
>                HETATM 5744  O   HOH B 362
>                HETATM 5745  O   HOH B 363
> 
>                29 Aralık 2010 19:12 tarihinde Justin A. Lemkul
>         <jalemkul at vt.edu <mailto:jalemkul at vt.edu>
>                <mailto:jalemkul at vt.edu <mailto:jalemkul at vt.edu>>
>         <mailto:jalemkul at vt.edu <mailto:jalemkul at vt.edu>
> 
>                <mailto:jalemkul at vt.edu <mailto:jalemkul at vt.edu>>>> yazdı:
> 
> 
> 
> 
>                   ahmet yıldırım wrote:
> 
>                       Dear Mark,
> 
>                       The chain identifier have continuous. In sequence does
>                not show
>                       any problem.
> 
> 
> 
>                   Then you're not looking at the right contents; pdb2gmx
>         wouldn't
>                   complain otherwise.  Usually HETATM entries like HOH
>         (water) are
>                   after all protein chains, so you might have chains A,
>         B, C,
>                etc for
>                   protein followed by A, B, C, etc for water.  Have a
>         more thorough
>                   look through the .pdb file.
> 
>                   -Justin
> 
> 
>                       29 Aralık 2010 15:10 tarihinde Mark Abraham
>                       <Mark.Abraham at anu.edu.au
>         <mailto:Mark.Abraham at anu.edu.au> <mailto:Mark.Abraham at anu.edu.au
>         <mailto:Mark.Abraham at anu.edu.au>>
>                <mailto:Mark.Abraham at anu.edu.au
>         <mailto:Mark.Abraham at anu.edu.au> <mailto:Mark.Abraham at anu.edu.au
>         <mailto:Mark.Abraham at anu.edu.au>>>
>                       <mailto:Mark.Abraham at anu.edu.au
>         <mailto:Mark.Abraham at anu.edu.au>
>                <mailto:Mark.Abraham at anu.edu.au
>         <mailto:Mark.Abraham at anu.edu.au>>
>                       <mailto:Mark.Abraham at anu.edu.au
>         <mailto:Mark.Abraham at anu.edu.au>
>                <mailto:Mark.Abraham at anu.edu.au
>         <mailto:Mark.Abraham at anu.edu.au>>>>> yazdı:
> 
> 
>                          On 29/12/2010 10:12 PM, ahmet yıldırım wrote:
> 
>                              Dear users,
> 
>                              ab at ubuntu:~/Desktop/3O87$ pdb2gmx -f 3O87.pdb
>                -water tip3p
> 
>                              Select the Force Field:
>                              5: OPLS-AA/L all-atom force field (2001
>         aminoacid
>                dihedrals)
> 
>                              Fatal error:
>                              Chain identifier 'A' was used in two
>                non-sequential blocks
>                              (residue 710, atom 54 49)
> 
>                              What should I do to correct this error?
> 
> 
>                          Look at the entries whose chain identifier is
>         A, and
>                see why they
>                          are non-sequential, and take suitable action to
>                remedy. You
>                       may need
>                          to Google for the PDB file format if you don't
>         already
>                       understand it.
> 
>                          Mark
> 
> 
>     -- 
>     ========================================
> 
>     Justin A. Lemkul
>     Ph.D. Candidate
>     ICTAS Doctoral Scholar
>     MILES-IGERT Trainee
>     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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> 
> 
> 
> -- 
> Ahmet YILDIRIM

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

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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