[gmx-users] interchain bond

[Velia Minicozzi]

Dear gromacs users,

I have two identical peptides which should bind one metal ion. I guess
I have not understood how I can make this bond.

I labeled the two peptides with different chain identifier otherwise
pdb2gmx does not understand that they are two peptides and not one
protein. The metal is labeled with a third identifier, and I modified
the ffoplsaabon.itp file inserting this bond and the specbond.dat file.

Having 3 chains I have 3 different itp files and one top file in which
all of the itp are called. Unfortunately in none of the itp files nor in
the top file there is any reference to this bond I created, and after
some time of MD simulation two of the atoms "bound" to the metal fly
away even if I use constraints on all bonds.

I guess I didn't create those bonds correctly. How should I do?

Any help is welcome!

Best,

Velia