Construction of a junction DNA nanostructure and modulation of the junction switching to quadruplexes.

Yanwei Cao,Renjun Pei,Xinhua Guo,Yang Li,Xiaoxuan Xiang,Yuting Yan

doi:10.1098/rsos.171337

Abstract

A junction DNA nanostructure has been successfully built in lithium acetate buffer solution at a near-neutral pH value through the connection of two slipped junction structures that are formed by G-rich and C-rich strands. The GC-rich duplex junctions in the nanostructure can be switched to G-quadruplexes and i-motifs in weakly acidic potassium acetate solution, which leads to the assembly of DNA nanostructures composed of alternating quadruplex and duplex DNA structures. The transformation between different DNA nanoarchitectures may be applied to the operation of ‘DNA nanomachines’.

Highlights

DNA molecules are a promising material for the construction of nanoscale structures because of their low cost of synthesis, high specificity of assembly and conformational flexibility
The Circular dichroism (CD) signal exhibits an obvious enhancement at around 290 nm when DNA sample 3 is titrated with pH 4.5 KOAc buffer; this result is suggestive of a structural shift from the duplex junction to the four-stranded DNA conformation containing bimolecular i-motifs and antiparallel G-quadruplexes [27]
Our results demonstrate that these monomers can assemble into stable junction DNA nanostructures, as confirmed by CD spectroscopy, native-polyacrylamide gel electrophoresis (PAGE) and Atomic force microscopy (AFM) experiments

Summary

Introduction

DNA molecules are a promising material for the construction of nanoscale structures because of their low cost of synthesis, high specificity of assembly and conformational flexibility. Duplex DNA structures can be cleaved at certain sites by the invasion of homologous DNA strands, which leads to the formation of DNA helix junctions. Junction structures have been found to occur during the processes of gene conversion or genetic recombination [1,2]. They serve as excellent templates for the construction of DNA supramolecules. Seeman [3] established a stable four-stranded DNA junction, in which each strand contained a unique single-stranded sticky

Methods

Results

Conclusion