[gmx-users] Regarding generating distance restraint

[Chinmai P]

Hi,
I have a system in which a part of my protein molecule is manually
 inserted inside a liposome.
However, due to high mobility of lipids, the protein is coming out of the
liposome.
Can you please suggest ways to stabilize the system?
One way I thought was to generate a distance restraint between COM of
liposome and COM of tip residues of protein inserted inside the liposome.
however, the distance restraint explained in gromacs manual were for
individual atoms.
Please suggest me how to generate  distance restraint for COM of group of
atoms.

Sincerely,
 Chinmai