Nonenzymatic ligation of oligodeoxyribonucleotides on a duplex DNA template by triple-helix formation

We report that a double-stranded DNA template can direct the sequence-specific formation of a phosphodiester linkage between oligodeoxyribonucleotides in aqueous solution by juxtaposing the termini head-to-tail in a triple-helical complex (Figure 1). A triple-stranded complex can be formed when a pyrimidine oligodeoxynucleotide binds in the major groove of duplex DNA parallel to the purine Watson-Crick strand. In the complex, sequence specificity for the condensation of oligodeoxynucleotides is directed by Hoogsteen base pairing.