Functionalization of DNA by the base pair-mimic nucleosides

We developed the base pair-mimic nucleosides tethering the phenyl group and the naphtyl group, synthesized from deoxyadenosine (Aphe and Anaph) and deoxycytidine (Cphe and Cnaph). Structure and the thermal stability of the DNA duplexes containing the deoxyadenosine derivatives or the deoxycytidine ones in the middle of a DNA strand were obtained by the CD spectra and the UV melting curves. The DeltaGo37 values among DNA duplexes containing Aphe-A, Aphe-G, Aphe-C and Aphe-T pair differed only by 1.9 kcal mol(-1). The DNA duplexes containing Cphe also showed the DeltaGo37 values differed by 1.0 kcal mol-1 despite opposite base nucleotide, except the duplex containing the Cphe-G pair. Interestingly, the duplex consisting of the DNA containing the base pair-mimic nucleosides and the complementary RNA strand caused the site-selective RNA hydrolysis except the Cphe-G pair. This data suggests that the Cphe has an ability of forming the base pair with guanosine.