title: A twisting electronic nanoswitch made of DNA.
abstract: Single-stranded DNAs and RNAs that are rich in the nucleobase guanine form four-stranded G-quadruplexes, which are held together by hydrogen-bonded guanine quartets. In aqueous solution, both DNA duplexes and G-quadruplexes are modest conductors of electrical charge. A tight, topologically constrained DNA construct called twDNA is now reported, in which a core of four guanine-rich single strands structurally and electronically links together four DNA double helices. The addition and removal of K(+) or Sr(2+) cations promote alternative conformers of twDNA, which have strikingly distinct electronic properties. Unlike DNA mechano-electronic switches that require large conformational changes, twDNA requires only modest twisting/untwisting structural attenuations to achieve electronic switching.
authors.affiliation: Department of Molecular Biology & Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6 (Canada).
authors.forename: Yu Chuan
authors.initials: YC
authors.lastname: Huang
authors.forename: Dipankar
authors.initials: D
authors.lastname: Sen
mesh_terms: D004277:DNA, Single-Stranded / Q000737:chemistry*; D004583:Electrons; D049329:Nanostructures / Q000737:chemistry*; D011188:Potassium / Q000737:chemistry*; D013324:Strontium / Q000737:chemistry*
chemical_list: D004277:DNA, Single-Stranded; D011188:Potassium; D013324:Strontium
keywords: DNA structures; G-quadruplexes; cations; electrophoresis; nanostructures