[gmx-users] RMS deviation after position restraint dynamics

[sukesh chandra gain]

Dear All,
I am running position restraint dynamics to restrain the atom positions 
of the protein to restrict their movement in the simulation. Then, how 
could there be any RMS deviation for the protein before and after the 
position restraint dynamics run? (Although the deviation is very little).
Could you please explain why is the deviation?
Thank You,
Regards,
Sukesh