Synthesis and triplex forming ability of conformationally locked oligonucleotides containing unnatural nucleobases: efficient recognition of a C.G interruption.

In order to develop a novel nucleoside analogue which recognizes C.G interruption in homopurine.homopyrimidine DNA, we designed and synthesized a conformationally locked nucleoside analogue, 1-(2-O,4-C-methylene-beta-D-ribofuranosyl)pyridin-2-one (4), and introduced it into a triplex-forming oligonucleotide (TFO). On melting temperature (Tm) measurements, the unprecedented C.G base recognition ability of 4 was observed.