[gmx-users] position restrains while pull simulation

[shivangi nangia]

Dear gmx-users,

I am doing a pull simulation in CG MARTINI and following the tutorial:
http://bevanlab.biochem.vt.edu/Pages/Personal/justin/gmx-tutorials/umbrella/05_pull.html


My systems contains POPC and cardiolipin (grouped as Lipid in index file),
protein, water and ions.

I want to position restrain the Lipid.

I used genrestr to create an .itp for the lipid (both popc and cardiolipin
combined)

I included the following at the end of both cardiolipin and popc respective
.itp files:
#ifdef POSRES_POPC_CARD
#include "posre_popc_card.itp"
#endif

In my .mdp file I included:
define = -DPOSRES_popc_card

I was able to successfully compile and generate .tpr file to do the pull
simulations.

I noticed that after the pull, the lipid beads are also getting
"drained/stretched" along with the protein.

Could you please guide as to why this may be happening even though I have
the restrains on.


Kindly help.


Thanks,
sxn