[gmx-users] Change restraints during md

[Mark Abraham]

Michal Kolinski wrote:
> Hello all.
> 
> I wonder is there a way for turning off the distance restraints during 
> the md simulation.
> I’m currently investigation different binding modes of a small
> ligand inside the active site of the receptor protein. 
> I use restraints to force a proper orientation of ligand
> inside the active site during the first stages of the simulation.
> Then I would like to slowly turn off the restraints between protein and 
> small
> molecule (without a rapid change in distance restraints force) to
> investigate the complex stability. 
> Maybe someone knows how to implement
> it in Gromacs code?  Please give me some advice.

You could do it in a stepwise fashion, varying the .top file only for 
successive restarts, rather than tweaking with the C code.

Mark