Synthesis and characterization of ruthenium(II)-oligopyridine-peptide conjugates. Interactions of the diasteromeres Delta- and Lambda-[Ru(bpy)(2) (4-COY-4 '-Mebpy)]Cl-2 (Y = Gly-Lys(1)-Lys(2)CONH(2), Lys(1)-Gly-Lys(2)CONH(2), Lys(1)-Lys(2)-GlyCONH(2)) with the oligonucleotide d(5 '-CGCGAATTCGCG-3 ')(2)