Lei Zhou wrote:
Hi,

Thank you for the answers. So I should use vacuum force field for the all-atom NM analysis. But if I want to add a layer of explicit water molecules as some papers did, which force field should I use?

Depends on how much water :)
Maybe read those papers a bit more carefully, but in that case full charges would be OK too I'd say.

Thanks you.

Lei Zhou



On 5/16/06, *David van der Spoel* <[EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>> wrote:

    Lei Zhou wrote:
     > Hi,
     >
     > Actually the major purpose was to extract the C-alpha components
     > from all-atom analysis, and then compare the result with other
     > approaches, like the PCA analysis or the GNM you mentioned. There
    was
     > some discussion on this before. I guess an easy way is still to use
     > g_nmens to generate an ensemble and run PCA on it?
     >
     > I am still puzzled by an old question I have asked. For the
    all-atom NM
     > analysis, which force field is better, G43a1 or G43b1 (vacuum)? If I
     > choose the normal distribution (G43a1), maybe I should use an epsilon
     > value of 2-4 with treatments of cut-off and rcoulomb=0?

    You should never use epsilon_r other than 1, as your protein will
    explode or implode.

    You can use the vacuum force field, it makes sense in this case.

     >
     > Thank you.
     >
     > Lei Zhou
     >
     >
     > On 5/16/06, *Erik Lindahl* <[EMAIL PROTECTED]
    <mailto:[EMAIL PROTECTED]>
     > <mailto:[EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>>> wrote:
     >
     >     Hi,
     >
     >     On May 15, 2006, at 10:02 PM, Lei Zhou wrote:
     >
     >      > Hi,
     >      >
     >      > I am trying to convert the binary Hessian matrix ( nm.mtx)
    into a
     >      > readable ascii format. According to the recommendations on
    this
     >      > email list, I rename the nm.mtx to nm.trr and tried to use
    gmxdump.
     >      > However, there is an error message liketrn version:
     >      >
     >      > Program gmxdump, VERSION 3.3.1
     >      > Source code file: trnio.c, line: 69
     >      > Fatal error:
     >      > Float size 401. Maybe different CPU?
     >      >
     >      > I am using gromacs 3.3.1. Also I am wondering there is any
    new
     >      > update on the extration of C-alpha modes based on the all-atom
     >      > Hessian matrix? Thanks for the help.
     >
     >     We had to discard the old Hessian format when introducing the
    sparse
     >     matrix representation to enable NMA for huge molecules. The
    easiest
     >     way to extract the data is probably to have a look in src/tools/
     >     gmx_nmeig.c.
     >
     >     As for C-alpha modes, projections of orthogonal vectors onto a
     >     subspace won't be orthogonal in that subspace, so per
    definition they
     >     are not "normal" modes for C-alpha. If you really want
    Ca-only modes
     >     you are probably better of with an elastic network model online
     >     server, e.g. http://lorentz.immstr.pasteur.fr
     >     <http://lorentz.immstr.pasteur.fr> .
     >
     >     Cheers,
     >
     >     Erik
     >
     >     _______________________________________________
     >     gmx-users mailing list    gmx-users@gromacs.org
    <mailto:gmx-users@gromacs.org>
     >     <mailto: gmx-users@gromacs.org <mailto:gmx-users@gromacs.org>>
     >     http://www.gromacs.org/mailman/listinfo/gmx-users
     >     Please don't post (un)subscribe requests to the list. Use the
     >     www interface or send it to [EMAIL PROTECTED]
    <mailto:[EMAIL PROTECTED]>
     >     <mailto:[EMAIL PROTECTED]
    <mailto:[EMAIL PROTECTED]>>.
     >     Can't post? Read http://www.gromacs.org/mailing_lists/users.php
     >
     >
     >
     >
    ------------------------------------------------------------------------

     >
     > _______________________________________________
     > gmx-users mailing list    gmx-users@gromacs.org
    <mailto:gmx-users@gromacs.org>
     > http://www.gromacs.org/mailman/listinfo/gmx-users
     > Please don't post (un)subscribe requests to the list. Use the
     > www interface or send it to [EMAIL PROTECTED]
    <mailto:[EMAIL PROTECTED]>.
     > Can't post? Read http://www.gromacs.org/mailing_lists/users.php


    --
    David.
    ________________________________________________________________________

    David van der Spoel, PhD, Assoc. Prof., Molecular Biophysics group,
    Dept. of Cell and Molecular Biology, Uppsala University.
    Husargatan 3, Box 596,          75124 Uppsala, Sweden
    phone:  46 18 471 4205          fax: 46 18 511 755
    [EMAIL PROTECTED]
    <mailto:[EMAIL PROTECTED]>    [EMAIL PROTECTED]
    <mailto:[EMAIL PROTECTED]>   http://folding.bmc.uu.se
    ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

    _______________________________________________
    gmx-users mailing list    gmx-users@gromacs.org
    <mailto:gmx-users@gromacs.org>
    http://www.gromacs.org/mailman/listinfo/gmx-users
    <http://www.gromacs.org/mailman/listinfo/gmx-users>
    Please don't post (un)subscribe requests to the list. Use the
    www interface or send it to [EMAIL PROTECTED]
    <mailto:[EMAIL PROTECTED]>.
    Can't post? Read http://www.gromacs.org/mailing_lists/users.php



------------------------------------------------------------------------

_______________________________________________
gmx-users mailing list    gmx-users@gromacs.org
http://www.gromacs.org/mailman/listinfo/gmx-users
Please don't post (un)subscribe requests to the list. Use the www interface or send it to [EMAIL PROTECTED]
Can't post? Read http://www.gromacs.org/mailing_lists/users.php


--
David.
________________________________________________________________________
David van der Spoel, PhD, Assoc. Prof., Molecular Biophysics group,
Dept. of Cell and Molecular Biology, Uppsala University.
Husargatan 3, Box 596,          75124 Uppsala, Sweden
phone:  46 18 471 4205          fax: 46 18 511 755
[EMAIL PROTECTED]       [EMAIL PROTECTED]   http://folding.bmc.uu.se
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
_______________________________________________
gmx-users mailing list    gmx-users@gromacs.org
http://www.gromacs.org/mailman/listinfo/gmx-users
Please don't post (un)subscribe requests to the list. Use the www interface or send it to [EMAIL PROTECTED]
Can't post? Read http://www.gromacs.org/mailing_lists/users.php

Reply via email to