[gmx-users] constraint force

[Kay Gottschalk]

Hi all,

I want to calculate the constraint force between two proteins at 
defined distances. For this, I already translated the proteins along 
the vector connecting them. Now I'd like to let the rotate for 
equilibration, but not translate. Is it correct to use the pull code 
with :
runtype = constraint
group_1 = protein_A
reference_group = protein_B
reftype = com
pulldim = N N N
constraint_direction = 1.0 1.0 1.0 ?
How long would I have to let it run (1ns, 5ns...) for meaningful 
results? Is it enough to check convergence by RMSD, constraint force 
and stop when it converged?
Thanks for your help!
Kay.