title: An ion-controlled four-color fluorescent telomeric switch on DNA origami structures.
abstract: The folding of single-stranded telomeric DNA into guanine (G) quadruplexes is a conformational change that plays a major role in sensing and drug targeting. The telomeric DNA can be placed on DNA origami nanostructures to make the folding process extremely selective for K(+) ions even in the presence of high Na(+) concentrations. Here, we demonstrate that the K(+)-selective G-quadruplex formation is reversible when using a cryptand to remove K(+) from the G-quadruplex. We present a full characterization of the reversible switching between single-stranded telomeric DNA and G-quadruplex structures using Förster resonance energy transfer (FRET) between the dyes fluorescein (FAM) and cyanine3 (Cy3). When attached to the DNA origami platform, the G-quadruplex switch can be incorporated into more complex photonic networks, which is demonstrated for a three-color and a four-color FRET cascade from FAM over Cy3 and Cy5 to IRDye700 with G-quadruplex-Cy3 acting as a switchable transmitter.
authors.affiliation: Department of Chemistry, Physical Chemistry, University of Potsdam, Karl-Liebknecht Str. 24-25, 14476 Potsdam, Germany. olejko@uni-potsdam.de bald@uni-potsdam.de.
authors.forename: L
authors.initials: L
authors.lastname: Olejko
authors.forename: P J
authors.initials: PJ
authors.lastname: Cywiński
authors.forename: I
authors.initials: I
authors.lastname: Bald
mesh_terms: D004247:DNA / Q000737:chemistry*; D005456:Fluorescent Dyes; D054856:G-Quadruplexes; D007477:Ions; D016615:Telomere / Q000737:chemistry*
chemical_list: D005456:Fluorescent Dyes; D007477:Ions; D004247:DNA