Properties and application of oligodeoxynucleotides containing the naphthyridine:imidazopyridopyrimidine base pairs with the ability to form four hydrogen bonds.

As our continuing study to develop base pairing motifs which stabilize and regulate DNA structure, we designed novel 1,8-naphthyridine C-nucleosides possessing Na-O(N) and Na-N(O) bases. These C-nucleosides formed two sets of naphthyridine:imidazopyridopyrimidine base pairing motifs (Na-O(N):Im-N(O) and Na-N(O):Im-O(N)) with four hydrogen bonds, and duplexes containing the pairs were markedly thermally stabilized independent of the manner in which the new pairs are incorporated.