Construction and Assembly of Branched Y-Shaped DNA: ``Click'' Chemistry Performed on Dendronized 8-Aza-7-deazaguanine Oligonucleotides

Abstract

Branched DNA was synthesized from tripropargylated oligonucleotides by the Huisgen-Meldal-Sharpless cycloaddition using ``stepwise and double click'' chemistry. Dendronized oligonucleotides decorated with 7-tripropargylamine side chains carrying two terminal triple bonds were further functionalized with bis-azides to give derivatives with two terminal azido groups. Then, the branched side chains with two azido groups or two triple bonds were combined with DNA-fragments providing the corresponding clickable function. Both concepts afforded branched (Y-shaped) three-armed DNA. Annealing of branched DNA with complementary oligonucleotides yielded supramolecular assemblies. The concept of ``stepwise and double click'' chemistry combined with selective hybridization represents a flexible tool to generate DNA nanostructures useful for various purposes in DNA diagnostics, delivery, and material science applications.