Stabilization of A-type nucleic acid duplexes by novel oligodiaminosaccharides

Novel oligodiaminosaccharides, alpha-(1-->4)-linked-2,6-diamino-2,6-dideoxy-D-glucopyranose oligomers, were designed and synthesized to bind to A-type nucleic acid duplexes, such as RNA duplexes. Using properly designed glycosyl donors and glycosyl acceptors, an alpha-selective glycosylation was achieved. A chain elongation cycle was established and the oligodiaminosaccharides bearing the alpha-glycoside bonds (1-4mer) were synthesised. Analyses of their interactions with oligonucleotide duplexes were performed by using CD spectrometry and UV melting experiments. These experiments revealed that the 3mer and 4mer were found to remarkably stabilize RNA-RNA and RNA-DNA duplexes with small structural changes.