Ab initio studies of aromatic-aromatic and aromatic-polar interactions in the binding of substrate and inhibitor to dihydrofolate reductase.

Aromatic-aromatic and aromatic-polar interactions are investigated by performing ab initio Hartree-Fock calculations. Binding energies and optimum distances between subsystems are obtained. It is found that the binding energy between two benzene rings is of 3.1 kcal/mol when correlation effects are included, while the serine aromatic complexes energies of binding range from 1.9 to 3.1 kcal/mol.