Synthesis of oligodeoxynucleotides incorporating 2-N-carbamoylguanine and evaluation of the hybridization properties

Previously, we reported 2-N-carbamoylguanine (cmG) as a guanine analog. We further studied the synthetic protocol and hybridization properties of oligodeoxynucleotides (ODNs) incorporating cmG. These ODNs were synthesized using the phosphoramidite of cmG without protection of the 6-O position. However, the isolated products were contaminated with deacylated products having guanine in place of cmG. The detailed analysis of the synthetic process suggested that the deacylation resulted from the reaction of the carbamoyl moiety with capping reagents. Protection of the 6-O position suppressed the side reaction. The thermal stability of the DNA duplexes incorporating cmG was analyzed. An analysis of T_m values revealed that the base discrimination ability of cmG was comparable to or higher than that of the canonical guanine depending on the flanking bases.