nishap.pa...@utoronto.ca wrote:
Okay so I tried to analyze the torsion using g_chi and g_rama for one
glycine zwitterion in water. for g_rama I didn't see anything in
xmgrace, and same for g_chi. I used this command for g_chi
g_chi -f traj.xtc -s gly.gro -phi -psi
When I run the command it says 1 residue with dihedrals found , 2
dihedrals found. But when I open the log file its empty and so are the
histo-phi/psiGLY.xvg plots. I tried using g_dih but it says:
Found 0 phi-psi combinations
For a zwitterion, these torsions don't exist. To measure phi, you need at least
C-N-CA-N, and for psi N-CA-C-N. For a single zwitterion, you have only N-CA-C.
You need at least a dipeptide.
-Justin
I am not sure how to check for all torsion convergence for my glycine
zwitterion molecule. Am I missing something in the command line?
-Nisha P
Quoting chris.ne...@utoronto.ca:
Nisha,
The approach is dictated by the goal. What do you want from this? and
why are you doing it? e.g. if you want to test the FF, then it is a
good idea to at least include US as a part of your strategy; if you
want to determine if 100 ns of equilibrium sampling is sufficient to
converge all torsions, then obviously you should not be doing US. In
any event, would start by running some equilbrium simulations and
analyzing the torsions with g_rama, g_chi, g_dih, etc. Be sure to read
through the -h output of each program as there are some nuances.
Chris.
-- original message --
Hello,
I would like to do conformational sampling for my simulation of
one glycine in its zwitterionic form in water and obtain a PMF curve
to see if the system is equilibrated and that all possible torsions
are covered for my 100ns run. I am not sure how to approach this
issue. Is there a tutorial I can follow? Do I need to do umbrella
sampling and use WHAM to extract PMF?
I would appreciate some help!
Thanks.
Nisha P.
--
gmx-users mailing list gmx-users@gromacs.org
http://lists.gromacs.org/mailman/listinfo/gmx-users
Please search the archive at http://www.gromacs.org/search before
posting!
Please don't post (un)subscribe requests to the list. Use the
www interface or send it to gmx-users-requ...@gromacs.org.
Can't post? Read http://www.gromacs.org/mailing_lists/users.php
--
========================================
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
========================================
--
gmx-users mailing list gmx-users@gromacs.org
http://lists.gromacs.org/mailman/listinfo/gmx-users
Please search the archive at http://www.gromacs.org/search before posting!
Please don't post (un)subscribe requests to the list. Use the
www interface or send it to gmx-users-requ...@gromacs.org.
Can't post? Read http://www.gromacs.org/mailing_lists/users.php
