An efficient, sequence-specific method for crosslinking complementary oligonucleotides using binuclear platinum complexes.

The binuclear PtII complexes (trans-Pt(NH3)2Cl)2 (NH2(CH2)nNH2)]Cl2 (n = 4, 5 or 6), crosslink oligodeoxynucleotide-5'-phosphorothioates rapidly, specifically and efficiently to complementary single-stranded oligodeoxynucleotide targets. In the case that we investigated in detail, the most abundant crosslink is formed to the G residue complementary to the 5'-terminal C residue of the phosphorothioate. Less efficient crosslinking occurs to many other residues of the target. The same PtII complexes also bring about crosslinking efficiently to the polypurine tract in triple-helical DNA.