[gmx-users] .top file from .gro file

Mark Abraham Mark.Abraham at anu.edu.au
Thu Aug 20 02:25:20 CEST 2009


sunny mishra wrote:
> Hi Mark and Justin,
> Thanks for the valuable advise and I want to do the last test but before I
> proceed I just want to make sure If I am doing everything correct.

Justin's advice was also very sound. If your model lacks relevant atoms, 
you have more work to do. Surely the MARTINI scripts should be providing 
some warnings here?

> I got the 1K4C_cleanCG.seq file using grep command like this
> 
> grep -A 1 1K4c_clean CG 1K4C_cleanCG.txt > 1K4C_cleanCG.seq

Nobody's interested in what your command was "like". This also was not 
your command, since you've added a space to make "1K4c_clean CG" and 
still not given it a filename suffix. Write a script so you've got a 
reliable record, or copy and paste from your terminal. Accuracy and 
reproducibility are critically important.

Mark

> Now my next step is to get the .ssd file for 1K4C_cleanCG.pdb which I cannot
> get and in that case I have to use 1K4C_clean.pdb in order to get .ssd file.
> 
> And If i am correct here then my next step would be to get the .itp file for
> 1K4C_cleanCG. So my last question is that when I will use seq2itp.pl script
> which .seq file should I use and which .ssd file should I use to get the
> output .itp file. I mean this....
> 
> seq2itp.pl 1K4C_cleanCG.seq 1K4C_clean.ssd > 1K4C_cleanCG.itp
> 
>                                            OR
> seq2itp.pl 1K4C_clean.seq 1K4C_clean.ssd > 1K4C_clean.itp
> 
> In the first command I don't think I can get the .ssd file( 1K4C_cleanG.ssd
> )  so thats why I am using 1K4C_clean.ssd. Now I dnt know if I am doing this
> wrong or correct but before proceeding i want to ask you guys to correct me
> at this point.
> 
> Thanks,
> 
> Sunny
> 
> On Wed, Aug 19, 2009 at 6:54 PM, Justin A. Lemkul <jalemkul at vt.edu> wrote:
> 
>> In addition to everything Mark said, also realize that there may be a
>> fundamental problem in everything you are doing: there are missing atoms in
>> the original 1K4C structure.  If you have not modeled them back in, the
>> appropriate CG particles will not necessarily all be placed in your CG
>> structure, but the topology will be written such that it expects all the
>> correct atoms to be there.
>>
>> At first glance, Arg117 is going to cause headaches - it is missing all
>> atoms beyond CB, and since CG and NE are necessary for MARTINI's definition
>> of an ARG residue, you can bet this will be a problem.
>>
>> -Justin
>>
>>
>> Mark Abraham wrote:
>>
>>> sunny mishra wrote:
>>>
>>>> Hi Justin,
>>>>
>>>> Thanks for the reply and here is the following which I am doing. I would
>>>> appreciate if you can point out my errors.
>>>>
>>>>
>>>> 1) I am working on 1K4C (KcSA) and i downloaded that from www.pdb.organd
>>>> after that I cleaned the PBD file, removed all the HETATOMS and ATOMS
>>>> with
>>>> ligand A & B and also removed the TER atoms. So my cleaned PDB file i.e.
>>>> (1K4C_clean.pdb) consists of atoms with ligands C and #of atoms are 765.
>>>>
>>>> 2) After getting the 1K4C_clean.pdb I converted the atomic structure to
>>>> CG
>>>> structure using awk script...something like this
>>>>
>>>> awk -f atom2cg.awk 1K4C_clean.pdb > 1K4C_cleanCG.pdb
>>>>
>>> Here you create 1K4C_cleanCG.pdb
>>>
>>>  3) Then I got the sequence of 1K4C_clean.pdb using vmd and saved that as
>>>> 1K4C_clean.txt and with the help of the following command I got the .seq
>>>> file...
>>>>
>>> But below you create your .itp starting from "1K4C_clean", which at least
>>> means you haven't copied your correct grep line, and might indicate the
>>> mismatch between your structure and topology.
>>>
>>>  grep -A 1 1K4C_clean 1K4C_clean.txt > 1K4C_clean.seq
>>>> 4) Then using dssp I got the .ssd file for 1K4C_clean.pdb....
>>>>
>>>> dsspcmbi 1K4C_clean.pdb 1K4C_clean.dssp
>>>> dssp2ssd.py 1K4C_clean.dssp -o 1K4C_clean.ssd
>>>>
>>>> 5) After preparing the secondary structure files I generated the MARTINI
>>>> topology files like this :
>>>>
>>>> seq2itp.pl 1K4C_clean.seq 1K4C_clean.ssd > 1K4C_clean.itp
>>>>
>>>> 6) The next step is to make the topology file and I made like this.....
>>>>
>>>> ; Include Martini Topology
>>>> #include "martini_v2.1.itp"
>>>>
>>>> ; Include protein topology
>>>> #include "1K4C_clean.itp"
>>>>
>>>>
>>>> [ system ]
>>>> ; Name
>>>> Membrane Protein
>>>>
>>>> [ molecules ]
>>>> ; compound       #mols
>>>> Protein            1
>>>>
>>>> 7) Then I made the .gro file using genbox.....
>>>>
>>>> genbox -cp 1K4C_cleanCG.pdb -box 10 10 10 -o 1K4C_cleanCG.gro
>>>>
>>>> (In the previous email as you said that I need to make the .gro file of
>>>> CG
>>>> structure of protein so I used 1K4C_cleanCG.pdb)
>>>>
>>> A .gro file is almost never essential. A structure file with a suitable
>>> periodic box can be.
>>>
>>>  8) Now I want to minimize the system.....
>>>> grompp -f em.mdp -c 1K4C_cleanCG.gro -p 1K4C_clean.top -maxwarn 10
>>>>
>>>> and then error comes...........
>>>>
>>>> :-)  G  R  O  M  A  C  S
>>>> (-:
>>>>
>>>>                   GROningen MAchine for Chemical Simulation
>>>>
>>>>                            :-)  VERSION 4.0.5  (-:
>>>>
>>>>
>>>>      Written by David van der Spoel, Erik Lindahl, Berk Hess, and others.
>>>>       Copyright (c) 1991-2000, University of Groningen, The Netherlands.
>>>>             Copyright (c) 2001-2008, The GROMACS development team,
>>>>            check out http://www.gromacs.org for more information.
>>>>
>>>>         This program is free software; you can redistribute it and/or
>>>>          modify it under the terms of the GNU General Public License
>>>>         as published by the Free Software Foundation; either version 2
>>>>             of the License, or (at your option) any later version.
>>>>
>>>>                                :-)  grompp  (-:
>>>>
>>>> Option     Filename  Type         Description
>>>> ------------------------------------------------------------
>>>>  -f         em.mdp  Input, Opt!  grompp input file with MD parameters
>>>>  -po      mdout.mdp  Output       grompp input file with MD parameters
>>>>  -c 1K4C_cleanCG.pdb  Input        Structure file: gro g96 pdb tpr tpb
>>>> tpa
>>>>  -r       conf.gro  Input, Opt.  Structure file: gro g96 pdb tpr tpb tpa
>>>>  -rb       conf.gro  Input, Opt.  Structure file: gro g96 pdb tpr tpb tpa
>>>>  -n      index.ndx  Input, Opt.  Index file
>>>>  -p 1K4C_clean.top  Input        Topology file
>>>>  -pp  processed.top  Output, Opt. Topology file
>>>>  -o      topol.tpr  Output       Run input file: tpr tpb tpa
>>>>  -t       traj.trr  Input, Opt.  Full precision trajectory: trr trj cpt
>>>>  -e       ener.edr  Input, Opt.  Energy file: edr ene
>>>>
>>>> Option       Type   Value   Description
>>>> ------------------------------------------------------
>>>> -[no]h       bool   no      Print help info and quit
>>>> -nice        int    0       Set the nicelevel
>>>> -[no]v       bool   yes     Be loud and noisy
>>>> -time        real   -1      Take frame at or first after this time.
>>>> -[no]rmvsbds bool   yes     Remove constant bonded interactions with
>>>> virtual
>>>>                            sites
>>>> -maxwarn     int    10      Number of allowed warnings during input
>>>> processing
>>>> -[no]zero    bool   no      Set parameters for bonded interactions
>>>> without
>>>>                            defaults to zero instead of generating an
>>>> error
>>>> -[no]renum   bool   yes     Renumber atomtypes and minimize number
>>>> of
>>>>
>>>> atomtypes
>>>>
>>>> Ignoring obsolete mdp entry 'title'
>>>> Ignoring obsolete mdp entry 'cpp'
>>>> Replacing old mdp entry 'unconstrained_start' by 'continuation'
>>>>
>>>> Back Off! I just backed up mdout.mdp to ./#mdout.mdp.8#
>>>> checking input for internal consistency...
>>>>
>>>> NOTE 1 [file em.mdp, line unknown]:
>>>>  For energy conservation with switch/shift potentials, rlist should be
>>>> 0.1
>>>>  to 0.3 nm larger than rcoulomb.
>>>>
>>>>
>>>> NOTE 2 [file em.mdp, line unknown]:
>>>>  For energy conservation with switch/shift potentials, rlist should be
>>>> 0.1
>>>>  to 0.3 nm larger than rvdw.
>>>>
>>>> processing topology...
>>>> Generated 0 of the 465 non-bonded parameter combinations
>>>> Excluding 1 bonded neighbours molecule type 'Protein'
>>>>
>>>> NOTE 3 [file 1K4C_clean.top, line 15]:
>>>>  System has non-zero total charge: 2.000000e+00
>>>>
>>>>
>>>>
>>>> processing coordinates...
>>>>
>>>> -------------------------------------------------------
>>>> Program grompp, VERSION 4.0.5
>>>> Source code file: grompp.c, line: 362
>>>>
>>>> Fatal error:
>>>> number of coordinates in coordinate file (1K4C_cleanCG.pdb, 209)
>>>>             does not match topology (1K4C_clean.top, 216)
>>>> -------------------------------------------------------
>>>>
>>>> I don't know where I have done the mistake...your help will be highly
>>>> appreciable in this case.
>>>>
>>> Here you've got a 7-atom difference, and...
>>>
>>>            -------------------------------------------------------
>>>>>>           Program grompp, VERSION 4.0.5
>>>>>>           Source code file: grompp.c, line: 362
>>>>>>
>>>>>>           Fatal error:
>>>>>>           number of coordinates in coordinate file (1K4C_cg.gro, 1127)
>>>>>>                       does not match topology (1K4C.top, 1166)
>>>>>>           -------------------------------------------------------
>>>>>>
>>> ...here you're different by 39 atoms. That indicates a procedure that
>>> differed by more than just not adding solvent.
>>>
>>> With a complex multi-step system preparation, you are much better served
>>> by writing the steps down in a shell script so that you really do things the
>>> same way every time. Science is still science, even on a computer, and your
>>> work must be reproducible. Moreover, then when you ask for help, you're not
>>> presenting contradictions and non sequiturs that frustrate attempts to help
>>> you :-)
>>>
>>> In any case, my earlier advice still applies - it should be a matter of 10
>>> minutes work to compare your clean .itp and .gro to see what atoms are
>>> causing the problem. Then, work backwards.
>>>
>>> Mark
>>> _______________________________________________
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>>>
>> --
>> ========================================
>>
>> Justin A. Lemkul
>> Ph.D. Candidate
>> 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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> 
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