title: Switchable enzyme/DNAzyme cascades by the reconfiguration of DNA nanostructures.
abstract: Mimicking cellular transformations and signal transduction pathways by means of biocatalytic cascades proceeding in organized media is a scientific challenge. We describe two DNA machines that enable the "ON/OFF" switchable activation and deactivation of three-component biocatalytic cascades. One system consists of a reconfigurable DNA tweezers-type structure, whereas in the second system the catalytic cascade proceeds on a switchable DNA clamp scaffold. The three-component catalytic cascades consist of β-galactosidase (β-Gal), glucose oxidase (GOx), and the K(+) -ion-stabilized hemin-G-quadruplex horseradish peroxidase (HRP)-mimicking DNAzyme. The hemin-G-quadruplex-bridged closed structure of the tweezers or clamp allows the biocatalytic cascades to operate (switched "ON''), whereas separation of the hemin-G-quadruplex by means of 18-crown-6-ether opens the tweezers/clamp structures, thus blocking the catalytic cascade (switched "OFF"). This study is complemented by two-component, switchable biocatalytic cascades composed of GOx and hemin-G-quadruplex assembled on hairpin-bridged DNA tweezers or clamp nanostructures.
authors.affiliation: Institute of Chemistry and The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904 (Israel).
authors.forename: Yuwei
authors.initials: Y
authors.lastname: Hu
authors.forename: Fuan
authors.initials: F
authors.lastname: Wang
authors.forename: Chun-Hua
authors.initials: CH
authors.lastname: Lu
authors.forename: Julia
authors.initials: J
authors.lastname: Girsh
authors.forename: Eyal
authors.initials: E
authors.lastname: Golub
authors.forename: Itamar
authors.initials: I
authors.lastname: Willner
mesh_terms: D055162:Biocatalysis; D021881:DNA, Catalytic / Q000737:chemistry* / Q000378:metabolism; D054856:G-Quadruplexes; D005949:Glucose Oxidase / Q000737:chemistry / Q000378:metabolism; D006427:Hemin / Q000737:chemistry / Q000378:metabolism; D049329:Nanostructures / Q000737:chemistry*
chemical_list: D021881:DNA, Catalytic; D006427:Hemin; D005949:Glucose Oxidase
keywords: G-quadruplexes; machine; nanostructures; nucleic acid; switch; tweezers