Evaluation of the 2 NH2A—T Pair in Hybridization, I Synthesis of the DNA/RNA Hybrid Oligomers Containing 2-Aminoadenosines

Abstract
DNA decamers containing 2-aminoadenosine were synthesized. Oligonucleotide duplexes including the 2 NH2A-T base pairs were prepared and their Tm profile examined. Contrary to expectation, elevation of the Tm value by the 2 NH2 group is very small in DNA/RNA duplexes. From the CD spectra measurement, we assume that the distortion of the B-DNA structure caused by scattered DNA/RNA base pairing diminishes the efficient hydrogen bonding and base stacking of the duplexes. It was also found that the DNA duplexes containing 2-aminoadenosine hybrids are considerably resistant to ribonuclease T2 or nuclease P1 digestion.