title: Mechatronic DNA devices driven by a G-quadruplex-binding platinum ligand.
abstract: Contractile duplexes are DNA double helices that incorporate two strategically placed patches of guanine-guanine (G·G) base mismatches. Such duplexes are cation-driven mechatronic devices, able to toggle between states with distinct mechanical and charge conduction properties. In aqueous lithium chloride solution contractile duplexes have an extended (E) and poorly conductive conformation; however, potassium ions drive them to a relatively conductive and structurally contracted (C) conformation, via intramolecular G-quadruplex formation. Here, we report that even in the absence of K(+) ions, a known G-quadruplex binding ligand, Pt-PIP [phenylphenanthroimidazole ethylenediamine platinum(II)] efficiently promotes the E→C transition, while a poor binder, Pt-bpy [bipyridine ethylenediamine platinum(II)], does not promote this transition. An examination of E→C transitions within two different designs for DNA contractile helices found an unexpected complexity: the formation of distinct C states, both electrically conductive, but possessing dissimilar DNA topologies. Ligand-driven DNA mechatronic devices such as these may constitute prototypes for electronic biosensors that identify G-quadruplex binding ligands.
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.affiliation: Department of Chemistry, McGill University, Montréal, Québec H3A 2K6, Canada.
authors.forename: Katherine J
authors.initials: KJ
authors.lastname: Castor
authors.affiliation: Department of Chemistry, McGill University, Montréal, Québec H3A 2K6, Canada.
authors.forename: Hanadi F
authors.initials: HF
authors.lastname: Sleiman
authors.affiliation: Department of Molecular Biology & Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada. Electronic address: sen@sfu.ca.
authors.forename: Dipankar
authors.initials: D
authors.lastname: Sen
mesh_terms: D001665:Binding Sites; D002942:Circular Dichroism; D004247:DNA / Q000737:chemistry*; D054856:G-Quadruplexes; D008024:Ligands; D009944:Organoplatinum Compounds / Q000737:chemistry*
chemical_list: D008024:Ligands; D009944:Organoplatinum Compounds; D004247:DNA
keywords: Bipyridine ethylenediamine platinum(II); Contractile switch; DNA; DNA conduction; DNA machine; G-quadruplex; Phenylphenanthroimidazole ethylenediamine platinum(II); Synapsable DNA