[gmx-users] g_rms matrix between wt and mutant

Mark Abraham Mark.Abraham at anu.edu.au
Tue Sep 13 10:17:38 CEST 2011


On 13/09/2011 6:11 PM, Shay Teaching wrote:
> Ok I tried that and it doesn't work:
> There's a fundamental difference between chains/no-chains topology, 
> namely the existence of peptide bond between chains, and the different 
> protonation state on the termini.
> In the chain-based topology there are several termini, and less 
> peptide bonds.
>
> This causes the no-chains-tpr to have different number of atoms, and 
> different protonation states.
> I tried using tpbconv to make a backbone-tpr, but it still gets me to 
> segmentation fault.

The idea behind Justin's original solution is still right. You need to 
provide two sets of corresponding atoms and those sets have to have the 
same size. So you need to construct two index groups that suit what you 
actually want to compare - say, the backbone atoms that are common to 
the two forms. That will require some thought, and playing around with 
make_ndx (or a text editor). Then use those to create subset .tpr and 
trajectory files as Justin suggested. Each form is likely to need its 
own customized index group to make the subset that is correct for it.

Mark

>
> So thanks, but I don't think it would work.
> -SA
>
> On Mon, Sep 12, 2011 at 11:47 PM, Shay Teaching 
> <shay.teaching at gmail.com <mailto:shay.teaching at gmail.com>> wrote:
>
>     Thanks, I'll try that, and post again if it works.
>
>
>     On Mon, Sep 12, 2011 at 6:20 PM, Justin A. Lemkul <jalemkul at vt.edu
>     <mailto:jalemkul at vt.edu>> wrote:
>
>
>
>         Shay Teaching wrote:
>
>             When I try to work the command on a small portion of the
>             backbone it seems to work just fine. But when I try the
>             entire backbone (which is composed of several _separate_
>             chains) I am getting segmentation fault.
>             Any workaround for that, so I can use the entire backbone?
>
>
>         Are there chain identifiers separating the proteins?  I don't
>         know if that would cause the problem, but it's possible.  In
>         that case, I'd suggest you start with a coordinate file and
>         topology without chain identifiers and generate a new .tpr
>         file (and then take the backbone atoms only with tpbconv).
>
>         -Justin
>
>             Thanks again,
>             -Shay
>
>
>             On Mon, Sep 12, 2011 at 5:29 PM, Justin A. Lemkul
>             <jalemkul at vt.edu <mailto:jalemkul at vt.edu>
>             <mailto:jalemkul at vt.edu <mailto:jalemkul at vt.edu>>> wrote:
>
>
>
>                Shay Teaching wrote:
>
>                    Hi all,
>                    (Gromacs 4.0.7): I am trying to make rms matrix
>             between one Wt
>                    trajectory and one mutant trajectory using the
>             following command:
>
>                    g_rms -f wt.xtc -f2 mutant.xtc -s wt.tpr -m -fit
>             rot+trans -n
>                    wt_backbone.ndx
>
>                    The file wt_backbone.ndx contains the backbone of
>             the protein
>                    (Backbone indices are identical between wt and mutant).
>
>                    The result is that I am getting a well deserved
>             error saying
>                    that wt.xtc and mutant.xtc has different number of
>             atoms (the
>                    tpr itself):
>                    Fatal error:
>                    Second trajectory (76128 atoms) does not match the
>             first one
>                    (76129 atoms)
>
>                    So the question becomes: Is there a (convenient)
>             way to produce
>                    rms-matrix between wt and mutant?
>                    Or perhaps circumvent this problem in some other way?
>
>
>                Use trjconv to write out new trajectories containing
>             only backbone
>                atoms of each protein, then use tpbconv to write a .tpr
>             file with
>                only backbone atoms in it (using index groups, if
>             necessary).  Then
>                run g_rms again with these new trajectories and .tpr file.
>                 Everything should match if the indices are chosen
>             correctly.
>
>                -Justin
>
>                --     ==============================__==========
>
>                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><http://vt.edu> |
>             (540) 231-9080 <tel:%28540%29%20231-9080>
>             <tel:%28540%29%20231-9080>
>
>             http://www.bevanlab.biochem.__vt.edu/Pages/Personal/justin
>             <http://vt.edu/Pages/Personal/justin>
>             <http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin>
>
>                ==============================__==========
>                --     gmx-users mailing list gmx-users at gromacs.org
>             <mailto:gmx-users at gromacs.org>
>             <mailto:gmx-users at gromacs.org <mailto:gmx-users at gromacs.org>>
>
>             http://lists.gromacs.org/__mailman/listinfo/gmx-users
>             <http://lists.gromacs.org/mailman/listinfo/gmx-users>
>                Please search the archive at
>             http://www.gromacs.org/__Support/Mailing_Lists/Search
>             <http://www.gromacs.org/Support/Mailing_Lists/Search>
>             before posting!
>                Please don't post (un)subscribe requests to the list.
>             Use the www
>                interface or send it to gmx-users-request at gromacs.org
>             <mailto:gmx-users-request at gromacs.org>
>             <mailto:gmx-users-request at gromacs.org
>             <mailto:gmx-users-request at gromacs.org>>.
>
>                Can't post? Read
>             http://www.gromacs.org/__Support/Mailing_Lists
>             <http://www.gromacs.org/Support/Mailing_Lists>
>
>
>
>         -- 
>         ========================================
>
>         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
>         <tel:%28540%29%20231-9080>
>         http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin
>
>         ========================================
>         -- 
>         gmx-users mailing list gmx-users at gromacs.org
>         <mailto:gmx-users at gromacs.org>
>         http://lists.gromacs.org/mailman/listinfo/gmx-users
>         Please search the archive at
>         http://www.gromacs.org/Support/Mailing_Lists/Searchbefore posting!
>         Please don't post (un)subscribe requests to the list. Use the
>         www interface or send it to gmx-users-request at gromacs.org
>         <mailto:gmx-users-request at gromacs.org>.
>         Can't post? Read http://www.gromacs.org/Support/Mailing_Lists
>
>
>
>
>

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://maillist.sys.kth.se/pipermail/gromacs.org_gmx-users/attachments/20110913/3f3029ac/attachment.html>


More information about the gromacs.org_gmx-users mailing list