Insight on the interaction of polychlorobiphenyl with nucleic acid-base.

The interaction between one polychlorobiphenyl (3,3',4,4',-tetrachlorobiphenyl, coded PCB77) and the four DNA nucleic acid-base is studied by means of quantum mechanics calculations in stacked conformations. It is shown that even if the intermolecular dispersion energy is the largest component of the total interaction energy, some other contributions play a non negligible role. In particular the electrostatic dipole-dipole interaction and the charge transfer from the nucleobase to the PCB are responsible for the relative orientation of the monomers in the complexes. In addition, the charge transfer tends to flatten the PCB, which could therefore intercalate more easily between DNA base pairs. From these seminal results, we predict that PCB could intercalate completely between two base pairs, preferably between Guanine:Cytosine pairs.