[gmx-users] Pulling simulation

[Naveen BK]

Dear all,

This question is regarding Umbrella sampling. My group 1 is substrate and
group 2 protein. Trying to pull substrate. In all the cases(for group 2), I
used either atom or residue for the center of mass [COM]. Now I want to run
a simulation by considering that COM of protein which may be present in the
vacuum or in the empty space. In other words, I don't want to fix any atom
or residue, I want to fix an empty space. I was not able to find any
solutions regarding that, if anyone could help me to figure it, would be
great.

-- 
Regards,
Naveen Krishna