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

Abstract

The interaction of the diastereomeric complexes Λ- and Δ-[Ru(bpy)2(m-GHK)]Cl2, (GHK = glycine-histidine-lysine) to the deoxynucleotide duplex d(5'-CGCGAATTCGCG-3')₂ was studied by means of ¹H NMR spectroscopy. The diastereomers interact with the oligonucleotide duplex differently. The Δ-[Ru(bpy)2(m-GHK)]Cl2 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 Λ-[Ru(bpy)2(m-bpy-GHK)]Cl2 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.