Well it is up to you to decide (or find out) if you think it should be protonated or not. I just had a quick look in the PDB file and there are no hydrogens on the ATP, plus the crystal structure was determined using an ATP analogue so I would not solely base my judgement on a structure of the ATP shown on the website which may contain a hydrogen on the gamma phosphate.

Tom

Chandan Choudhury wrote:
Thanks Tom.
Some how only the negative charges were being added in spreadsheet. So, I got charge around -12. I am simulating 1QHH. It has ATP in it, the structure of the ligand in the rcsb (http://www.pdb.org/pdb/explore/explore.do?structureId=1QHH) shows ATP with hydrogen.

--
Chandan kumar Choudhury
NCL, Pune
INDIA


On Mon, Feb 8, 2010 at 8:34 PM, Thomas Piggot <t.pig...@bristol.ac.uk <mailto:t.pig...@bristol.ac.uk>> wrote:

    Are you sure you added it up correctly? I get a number very close to -4.

    There is no hydrogen on the gamma phosphate as it was parameterised
    in this way. If the environment in which your ATP is located
    suggests that the gamma phosphate should be protonated then you need
    to use other ATP parameters which include this hydrogen (such as
    those in the GROMOS forcefield).


    Cheers

    Tom

    Chandan Choudhury wrote:

        Hi Tom!!
        Thanks for the information. I went through the paper and added
        the new O3 atom type.  One unusual thing I noticed was that the
        sum of the partial charges on the atoms of AT P at the last
        column of
        
http://personalpages.manchester.ac.uk/staff/Richard.Bryce/amber/cof/ATP.prep
        file is       -12.7145. How come fractional? and the hydrogens
        of phosphate are missing. How can it be overcome?
        Chandan

        --
        Chandan kumar Choudhury
        NCL, Pune
        INDIA


        On Sat, Feb 6, 2010 at 1:13 AM, TJ Piggot
        <t.pig...@bristol.ac.uk <mailto:t.pig...@bristol.ac.uk>
        <mailto:t.pig...@bristol.ac.uk <mailto:t.pig...@bristol.ac.uk>>>
        wrote:

                >From the Carlson et al. paper where these ATP
        parameters were
               published and

           through choosing the appropriate amber_X atom types from the .atp
           (and the corresponding values for these types in the nb and
        bon .itp
           files). As I mentioned previously you need to add a new O3
        atom type
           to these files based on the information in the Carlson paper.

           If you have a look at one of the entries from the
        ffamberXX.rtp file
           and work out how this is used by pdb2gmx it should become
        clear what
           you need to do to add the ATP to the forcefield.

           Cheers

           Tom


           --On Saturday, February 06, 2010 00:05:10 +0530 Chandan Choudhury
           <iitd...@gmail.com <mailto:iitd...@gmail.com>
        <mailto:iitd...@gmail.com <mailto:iitd...@gmail.com>>> wrote:


               Hi Thomas !

               Creating a new entry in the .rtp, nb.itp needs charge,
        radius,
               epsilon
               values etc. values. Where to get these values


               Chandan

               --
               Chandan kumar Choudhury
               NCL, Pune
               INDIA



               On Fri, Feb 5, 2010 at 6:54 PM, Thomas Piggot
               <t.pig...@bristol.ac.uk <mailto:t.pig...@bristol.ac.uk>
        <mailto:t.pig...@bristol.ac.uk <mailto:t.pig...@bristol.ac.uk>>>
               wrote:

               Not sure about amb2gmx.pl <http://amb2gmx.pl>
        <http://amb2gmx.pl> or acpypi but you

               can do this by hand. Consult
               the GROMACS manual (Chapter 4) for the equations to
        convert the
               parameters into GROMACS format.

               I would also say that the easiest way would be to create
        a new
               entry in
               the .rtp and then also add the appropriate bonded parameters
               into the
               bon.itp file, making sure to include the bonded
        parameters for
               the new O3
               atom type. Do note that you need to also add this new
        atom type
               for the
               O3 oxygen into the .atp file and the non-bonded
        parameters for
               the atom
               type into the nb.itp file.

               You can also add entries into the .hdb to allow pdb2gmx
        to add the
               appropriate hydrogens to your ATP if so desired. If not, your
               input pdb
               for pdb2gmx will need to have these hydrogens already
        included.

               Cheers

               Tom

               Chandan Choudhury wrote:


               Hello gmx users,
               I need to use ATP's parameter for amber port in gromacs. The
               atp.prep and
               frcmod.phos for ATP can be found at
               http://www.pharmacy.manchester.ac.uk/bryce/a
               <http://www.pharmacy.manchester.ac.uk/bryce/amber>

               _mdrun -s spc_25_eq.tpr -cpi state.cpi -c  spc_25_eq.pdb -o

               spc_25_eq.trr -e spc_25_eq.edr -g spc_25_eq.log  -append yes_

               mber <http://www.pharmacy.manchester.ac.uk/bryce/amber>.
        How can

               I use it in
               ffamber.
                The program amb2gmx.pl <http://amb2gmx.pl>
        <http://amb2gmx.pl> <http://amb2gmx.pl>

               needs amber to be installed,
               which is not present. Same with ACPYPI.


               Any suggestion will be very helpful.

               Chandan


               --
               Chandan kumar Choudhury
               NCL, Pune
               INDIA



               --
               Thomas Piggot
               University of Bristol, UK.
               --
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           ----------------------
           TJ Piggot

           t.pig...@bristol.ac.uk <mailto:t.pig...@bristol.ac.uk>
        <mailto:t.pig...@bristol.ac.uk <mailto:t.pig...@bristol.ac.uk>>

           University of Bristol, UK.

           --    gmx-users mailing list    gmx-users@gromacs.org
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-- Thomas Piggot
    University of Bristol, UK.
-- gmx-users mailing list gmx-users@gromacs.org
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--
Thomas Piggot
University of Bristol, UK.
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