Molecular modeling: The interactions between novel heteronuclear Pt-L-Zn complexes and DNA

The four novel complexes [{cis-PtCl(NH₃)(μ-4,4′-bipyridyl)ZnCl(terpy)}](ClO₄)₂ (C1), [{trans-PtCl(NH₃)(μ-4,4′-bipyridyl)ZnCl(terpy)}](ClO₄)₂ (C2), [{cis-PtCl(NH3)(μ-pyrazine)ZnCl(terpy)}](ClO₄)₂ (C3) and [{trans-PtCl(NH₃)(μ-pyrazine)ZnCl(terpy)}](ClO₄)₂ (C4) (where terpy = 2,2′:6′,2′′-terpyridine) were investigated using molecular docking as a powerful in silico method for determination of interaction between hetronuclear complexes and DNA.

The principal interaction between C1 complex and DNA came from H-bonds (at the sites DT19, DA18 nucleotides), and van der Waals forces. Likewise, connection between C2 complex and DNA included covalent H-bonds (DA18, DT19, DG4). On the other hand, complex C3 was bind with DC3, DG2 and DT19 nucleotide basis through conventional H-bonds. The complex C4 was bind with DG10, DT20 and DT19 through conventional H-bonds. Additionally, the complexes C1-C4 show that π interactions were also involved in their binding with DNA. The chelating ability of terpy ligands enhances the complex stability, while their planarity promotes intercalative interaction of the complexes with DNA due to π-stacking between the plane of the aromatic rings and DNA base pairs.