title: G-C content independent long-range charge transfer through DNA.
abstract: The interest in DNA as a building block for nano-electric sensors and devices stemmed from the ability to construct various nanometer-sized two and three-dimensional structures and its amazing positive charge conducting properties. However, since a positive charge migrates along DNA through the HOMO of G-C base-pairs, the conductivity of DNA strongly decreases with the increasing A-T base-pair content hampering the construction of nano-electric circuits in which the use of various sequence patterns is indispensable. In this chapter, we demonstrated that the charge transfer efficiency can be drastically increased in a G-C content independent manner by adjusting the HOMO-level of the A-T base-pair closer to that of the G-C base-pair. This was achieved either by substituting the N7 nitrogen of A with a C-H group (deazaadenine: Z) or substituting C2 hydrogen with an amino group (diaminopurine: D). Since Z and D selectively pair with T without significantly perturbing the thermo-stability of the duplex, Z and D can be used to increase the charge transfer efficiency through DNA while properly maintaining the sequence information carried by DNA.
authors.affiliation: The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Ibaraki, Osaka, 567-0047, Japan. kiyohiko@sanken.osaka-u.ac.jp
authors.forename: Kiyohiko
authors.initials: K
authors.lastname: Kawai
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Majima
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives* / Q000737:chemistry; D001482:Base Composition; D020029:Base Pairing; D001483:Base Sequence; D004247:DNA / Q000737:chemistry*; D004583:Electrons
chemical_list: D004247:DNA; D000225:Adenine