[gmx-users] Re: change in the secondary structure after simulation

Justin A. Lemkul jalemkul at vt.edu
Thu Jan 27 14:12:08 CET 2011



bharat gupta wrote:
> I don't think that there is any problem in the structure .. since I am 
> simulating the crystal structure taken from PDB ... and I have checked 
> the structure generated after pdb2gmx and solvation..
>  
> Since I am reapeating the simulation again I want to know and I am on 
> energy minimzation step I want to know .. how can I retrieve the 
> structure after minimization ..
> 

The structure after minimization (or any process done by mdrun) is contained in 
whatever filename you passed to the -c flag.  If you haven't specified any name, 
it is confout.gro.

-Justin

> On Thu, Jan 27, 2011 at 4:16 AM, Mark Abraham <Mark.Abraham at anu.edu.au 
> <mailto:Mark.Abraham at anu.edu.au>> wrote:
> 
>     On 27/01/2011 11:11 PM, bharat gupta wrote:
>>     I used the same .mdp files that are given in the lysozyme tutorial
>>     .. Since I was knowing what all parameters to change .. but after
>>     energy minimization and equilibration steps , the graphs that I
>>     got were fine ... even the rmsd graph of the final structure is
>>     also fine .. I have attached the final rmsd graph of the structure ..
> 
>     That suggests the problem was in the structure you started the
>     simulation from, like I've suggested a few times now :-)
> 
>     Mark
> 
>      
>>     On Thu, Jan 27, 2011 at 3:44 AM, Justin A. Lemkul <jalemkul at vt.edu
>>     <mailto:jalemkul at vt.edu>> wrote:
>>
>>
>>
>>         bharat gupta wrote:
>>
>>             I generated the secondary structure profile of structure
>>             retrieved from the last frame of the simulation ... In
>>             that profile those amino acids that are shown as loops in
>>             VMD doesnot have any secondary structure assignment ... it
>>             means that during simulation the structure got changed
>>             some how ... and It's really surprising ?? ... Can u tell
>>             me where can the fault be as I am planning to do the
>>             simulation again and this time I will check the structure
>>             after every step .. but for that I want to know how can I
>>             save the structure after every step say for eg. after
>>             energy minimization ..
>>
>>
>>         Secondary structure is dependent upon the chosen force field
>>         and the .mdp settings.  Since you've posted neither, there's
>>         no way to tell what might be to blame.
>>
>>         You can save more frequently by setting the proper output
>>         controls.  Read in the manual about the nst* options and set
>>         the accordingly.
>>
>>         -Justin
>>
>>             On Thu, Jan 27, 2011 at 8:35 PM, Justin A. Lemkul
>>             <jalemkul at vt.edu <mailto:jalemkul at vt.edu>
>>             <mailto:jalemkul at vt.edu <mailto:jalemkul at vt.edu>>> wrote:
>>
>>
>>
>>                Mark Abraham wrote:
>>
>>
>>
>>                    On 01/27/11, *bharat gupta *
>>             <bharat.85.monu at gmail.com <mailto:bharat.85.monu at gmail.com>
>>                    <mailto:bharat.85.monu at gmail.com
>>             <mailto:bharat.85.monu at gmail.com>>> wrote:
>>
>>                        I actually don't understand exactly what u are
>>             asking ..
>>                        since I am not an expert with gromacs..
>>
>>
>>                    Please leave the old context for the discussion in
>>             future
>>                    emails. Only you are paying so much attention to
>>             your work that
>>                    you can be sure of remembering things :-)
>>
>>                    If your simulation started with these strands
>>             unfolded, then
>>                    your problem is somewhere else. However, you have
>>             to be able to
>>                    tell us what was the initial conformation, and when
>>             your "first
>>                    trajectory frame" (per last email) happened in the
>>             simulation.
>>
>>
>>                I would also add that VMD does a fairly poor job
>>             sometimes of
>>                guessing secondary structure.  So if no beta strand was
>>             present in
>>                the very first frame, that doesn't necessarily mean the
>>             secondary
>>                structure wasn't stable, it just means VMD didn't
>>             display it properly.
>>
>>                -Justin
>>
>>                    Mark
>>
>>
>>                        I don't know when is was written .. Here are
>>             some lines from
>>                        the log files of simulation ...
>>                        Statistics over 1500001 steps using 300001 frames
>>
>>                          Energies (kJ/mol)
>>                                 Angle    Proper Dih. Ryckaert-Bell.  
>>                    LJ-14
>>                            Coulomb-14
>>                           7.35090e+03    4.37413e+02    3.60104e+03  
>>              5.26705e+03
>>                           2.58894e+04
>>                               LJ (SR)  Disper. corr.   Coulomb (SR)  
>>             Coul. recip.
>>                             Potential
>>                           1.05399e+05   -2.92853e+03   -6.79288e+05  
>>             -1.07015e+05
>>                          -6.41286e+05
>>                           Kinetic En.   Total Energy    Temperature
>>             Pres. DC (bar)
>>                        Pressure (bar)
>>                           1.03484e+05   -5.37802e+05    3.00003e+02  
>>             -2.37485e+02
>>                           1.02890e+00
>>                          Constr. rmsd
>>                           0.00000e+00
>>
>>                                 Box-X          Box-Y          Box-Z
>>                           7.42618e+00    7.42618e+00    7.42618e+00
>>
>>                          Total Virial (kJ/mol)
>>                           3.44183e+04    3.40020e+01   -1.17357e+01
>>                           3.42160e+01    3.45369e+04   -2.46337e+01
>>                          -1.16644e+01   -2.48479e+01    3.44949e+04
>>
>>                          Pressure (bar)
>>                           1.99809e+00    9.48448e-02    4.57909e-01
>>                           7.74354e-02    4.97824e-01    1.84797e+00
>>                           4.52125e-01    1.86535e+00    5.90776e-01
>>
>>                          Total Dipole (D)
>>                          -1.86272e+02    4.46310e+01    2.08554e+02
>>
>>                             T-Protein  T-non-Protein
>>                           2.99904e+02    3.00013e+02
>>
>>
>>                        M E G A - F L O P S   A C C O U N T I N G
>>
>>
>>                        There were in total 1502 frames (as shown in
>>             VMD )...
>>                        I don't know about how it compared with the
>>             coordinates of
>>                        the structure that I gave to grompp
>>
>>                        --------
>>
>>                        Pls guide
>>
>>
>>
>>
>>                        --             Bharat
>>                        Ph.D. Candidate
>>                        Room No. : 7202A, 2nd Floor
>>                        Biomolecular Engineering Laboratory
>>                        Division of Chemical Engineering and Polymer
>>             Science
>>                        Pusan National University
>>                        Busan -609735
>>                        South Korea
>>                        Lab phone no. - +82-51-510-3680, +82-51-583-8343
>>                        Mobile no. - 010-5818-3680
>>                        E-mail : monu46010 at yahoo.com
>>             <mailto:monu46010 at yahoo.com> <mailto:monu46010 at yahoo.com
>>             <mailto:monu46010 at yahoo.com>>
>>                        <mailto:monu46010 at yahoo.com
>>             <mailto:monu46010 at yahoo.com> <mailto:monu46010 at yahoo.com
>>             <mailto:monu46010 at yahoo.com>>>
>>
>>
>>
>>                --     ========================================
>>
>>                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
>>             <http://vt.edu/>> | (540) 231-9080
>>
>>                http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin
>>
>>                ========================================
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>>
>>             -- 
>>             Bharat
>>             Ph.D. Candidate
>>             Room No. : 7202A, 2nd Floor
>>             Biomolecular Engineering Laboratory
>>             Division of Chemical Engineering and Polymer Science
>>             Pusan National University
>>             Busan -609735
>>             South Korea
>>             Lab phone no. - +82-51-510-3680, +82-51-583-8343
>>             Mobile no. - 010-5818-3680
>>             E-mail : monu46010 at yahoo.com <mailto:monu46010 at yahoo.com>
>>             <mailto:monu46010 at yahoo.com <mailto:monu46010 at yahoo.com>>
>>
>>
>>         -- 
>>         ========================================
>>
>>         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
>>         http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin
>>
>>         ========================================
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>>
>>
>>     -- 
>>     Bharat
>>     Ph.D. Candidate
>>     Room No. : 7202A, 2nd Floor
>>     Biomolecular Engineering Laboratory
>>     Division of Chemical Engineering and Polymer Science
>>     Pusan National University
>>     Busan -609735
>>     South Korea
>>     Lab phone no. - +82-51-510-3680, +82-51-583-8343
>>     Mobile no. - 010-5818-3680
>>     E-mail : monu46010 at yahoo.com <mailto:monu46010 at yahoo.com>
>>
> 
> 
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> 
> 
> 
> -- 
> Bharat
> Ph.D. Candidate
> Room No. : 7202A, 2nd Floor
> Biomolecular Engineering Laboratory
> Division of Chemical Engineering and Polymer Science
> Pusan National University
> Busan -609735
> South Korea
> Lab phone no. - +82-51-510-3680, +82-51-583-8343
> Mobile no. - 010-5818-3680
> E-mail : monu46010 at yahoo.com <mailto:monu46010 at yahoo.com>
> 

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

Justin A. Lemkul
Ph.D. Candidate
ICTAS Doctoral Scholar
MILES-IGERT Trainee
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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