As I said before, the original PDB file is missing atoms. You have to model them back in before you do anything else, otherwise MARTINI will expect them to be there and they won't be!

-Justin

sunny mishra wrote:
Hi Justin and Mark,

I just realized that I have some missing atoms in my .gro file when I compared with .itp file and may be this is causing the problem. The atoms which are missing what should I do with them. Should I delete both from .itp and .gro file OR do i have to add in my .gro file and if I have to add them then how?

for example in my .itp file there are 2 ILE but in my .gro file there is only 1 ILE. So should i add another ILE in my .gro file or delete 2 ILE from .itp and 1ILE from .gro. Thanks in advance.

Sunny

On Wed, Aug 19, 2009 at 7:23 PM, sunny mishra <[email protected] <mailto:[email protected]>> wrote:


    Alright. Sounds good to me. let me check that out and i will let you
    know the progress.

    Thanks,

    Sunny


    On Wed, Aug 19, 2009 at 7:19 PM, Justin A. Lemkul <[email protected]
    <mailto:[email protected]>> wrote:



        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.

            I got the 1K4C_cleanCG.seq file using grep command like this

            grep -A 1 1K4c_clean CG 1K4C_cleanCG.txt > 1K4C_cleanCG.seq

            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.


        The .seq file should not depend at all on anything to do with
        the structure; the amino acid sequence is invariant.  You can
        download the FASTA sequence from the PDB and use that
        (accounting for any missing terminal residues); it shouldn't
        make a difference.

        -Justin

            Thanks,

            Sunny


            On Wed, Aug 19, 2009 at 6:54 PM, Justin A. Lemkul
            <[email protected] <mailto:[email protected]>
            <mailto:[email protected] <mailto:[email protected]>>> 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.org <http://www.pdb.org>
            <http://www.pdb.org> and

                       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 <http://vt.edu> <http://vt.edu> |
            (540) 231-9080

               http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin

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

        Justin A. Lemkul
        Ph.D. Candidate
        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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--
========================================

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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