Local electron correlation descriptions of the intermolecular stacking interactions between aromatic intercalators and nucleic acids

Abstract

Interaction energies for the binding of three intercalators to nucleic acid base pairs and base-pair steps are presented. Density fitting (DF) and local (L) correlation methods are employed, allowing use of basis sets appropriate for description of non-covalent interactions. In common with previous studies of stacking interactions, DF-LMP2 overestimates binding by as much as 50%. However, spin-component scaling (SCS) corrects for this effect, resulting in binding energies that support literature data obtained with small basis sets and/or density functional theory. The efficiency of this approach allows intercalators within base-pair steps to be studied, revealing substantial many body terms.