title: Development of a novel biosensing system based on the structural change of a polymerized guanine-quadruplex DNA nanostructure.
abstract: By inserting an adenosine aptamer into an aptamer that forms a G-quadruplex, we developed an adaptor molecule, named the Gq-switch, which links an electrode with flavin adenine dinucleotide-dependent glucose dehydrogenase (FADGDH) that is capable of transferring electron to a electrode directly. First, we selected an FADGDH-binding aptamer and identified that its sequence is composed of two blocks of consecutive six guanine bases and it forms a polymerized G-quadruplex structure. Then, we inserted a sequence of an adenosine aptamer between the two blocks of consecutive guanine bases, and we found it also bound to adenosine. Then we named it as Gq-switch. In the absence of adenosine, the Gq-switch-FADGDH complex forms a 30-nm high bulb-shaped structure that changes in the presence of adenosine to give an 8-nm high wire-shaped structure. This structural change brings the FADGDH sufficiently close to the electrode for electron transfer to occur, and the adenosine can be detected from the current produced by the FADGDH. Adenosine was successfully detected with a concentration dependency using the Gq-switch-FADGDH complex immobilized Au electrode by measuring response current to the addition of glucose.
authors.affiliation: Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan.
authors.forename: Yo
authors.initials: Y
authors.lastname: Morita
authors.forename: Wataru
authors.initials: W
authors.lastname: Yoshida
authors.forename: Nasa
authors.initials: N
authors.lastname: Savory
authors.forename: Sung Woong
authors.initials: SW
authors.lastname: Han
authors.forename: Masayuki
authors.initials: M
authors.lastname: Tera
authors.forename: Kazuo
authors.initials: K
authors.lastname: Nagasawa
authors.forename: Chikashi
authors.initials: C
authors.lastname: Nakamura
authors.forename: Koji
authors.initials: K
authors.lastname: Sode
authors.forename: Kazunori
authors.initials: K
authors.lastname: Ikebukuro
mesh_terms: D000241:Adenosine / Q000032:analysis*; D052157:Aptamers, Nucleotide / Q000737:chemistry* / Q000378:metabolism; D015374:Biosensing Techniques / Q000379:methods*; D054856:G-Quadruplexes; D042843:Glucose 1-Dehydrogenase / Q000378:metabolism; D006147:Guanine / Q000737:chemistry*; D049329:Nanostructures / Q000737:chemistry / Q000648:ultrastructure; D058105:Polymerization
chemical_list: D052157:Aptamers, Nucleotide; D006147:Guanine; D042843:Glucose 1-Dehydrogenase; D000241:Adenosine