ZINK in Protein

Dear all,
i have a protein, which is a dimer, and in each monomer there is a zink surrounded by 3 CYS and one HIS. i want to do md simulation, and i just want to keep it inside the protein. (at this point, i don’t need the ff parameter of zink, and i just want to keep it fixed inside the protein). i tried to add these lines at the end of my topol.top file:
[ intermolecular_interactions ]
[ distance_restraints ]
;ai aj type index type’ low up1 up2 fac
2197 1237 1 0 1 0.0 0.22 0.25 1.0
2197 869 1 0 1 0.0 0.22 0.25 1.0
2197 818 1 0 1 0.0 0.22 0.25 1.0
2197 1135 1 0 1 0.0 0.22 0.25 1.0

but still, zink escape from its position. what do you think i can do to fix this issue?

Have you enabled the usage of distance restraints in the md.mdp file?

You are absolutely right. I’d forgotten to activate the responsible parts in md.mdp. Thank you!

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