Molecular recognition of a thymine bulge by a high affinity, deazaguanine- based hydrogen-bonding ligand

7-Deazaguanine (7-DeG) was developed as a hydrogen-bonding module capable of enhanced recognition of uracil (U) and thymine (T); a water-soluble derivative displayed high affinity and selectivity toward DNA and RNA duplexes containing single T-and U-bulges.