[gmx-users] partial charges

[Joanne Hanna]

Hi

I was wodnering how the partial charges for ligands in the ffG43a2.rtp files were calculated, more specifically the ATP molecule.
I have calculated (fitted) charges for an AMP molecule using gaussian and 6-31g basis sets, however these charges are quite drastically different to the ATP charges, particularly on the adenine ring.
Also on an unrelated matter and probably a very trivial question but if i was wanting to use position restraints on atoms of 10 Kj/mol, in the posre.itp file this would correspond to values of 10 in each of the x y and z direction for each atom? is this correct?

Many thanks
Jo