1H NMR Study of the Enantioselective Binding of λ- and Δ-[Ru(bpy)2(m-bpy-GHK)]Cl2 to the Deoxynucleotide Duplex d(5'-C1G2C3G4A5A6T7T8C9G10C11G12-3')2

The interaction of the diastereomeric complexes Lambda- and Delta - [Ru(bpy)(2)(m - GHK)]Cl(2), (GHK = glycine-histidine-lysine) to the deoxynucleotide duplex d(5'-CGCGAATTCGCG-3')(2) was studied by means of (1)H NMR spectroscopy. The diastereomers interact with the oligonucleotide duplex differently. The Delta - [Ru(bpy)(2) (m - GHK)]Cl(2) is characterized by major groove binding close to the central part of the oligonucleotide, with both the peptide and the bipyridine ligand of the complex involved in the binding. The lambda - [Ru(bpy)(2) (m - bpy - GHK)]C(2) binds loosely, approaching the helix from the minor groove. The NMR analysis shows that the peptide (GHK) binding has a determinative role in the interactions of both diastereomers with the oligonucleotide.