title: Dynamics of Excess-Electron Transfer through Alternating Adenine:Thymine Sequences in DNA.
abstract: This paper presents the results of an investigation into the sequence-dependent excess-electron transfer (EET) dynamics in DNA, which plays an important role in DNA damage/repair. There are many published studies on EET in consecutive adenine:thymine (A:T) sequences (Tn), but those in alternating A:T sequences (ATn) remain limited. Here, two series of functionalized DNA oligomers, Tn and ATn, were synthesized with a strongly electron-donating photosensitizer, a trimer of ethylenedioxythiophene (3 E), and an electron acceptor, diphenylacetylene (DPA). Laser flash photolysis experiments showed that the EET rate constant of AT3 is two times lower than that of T3 due to the lack of π-stacking of Ts in AT3. Thus, it was indicated that excess-electron hopping is affected by the interaction between LUMOs of nucleotides.
authors.affiliation: The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047 (Japan), Fax: (+81) 6-6879-8499.
authors.forename: Shih-Hsun
authors.initials: SH
authors.lastname: Lin
authors.affiliation: The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047 (Japan), Fax: (+81) 6-6879-8499. fuji@sanken.osaka-u.ac.jp.
authors.forename: Mamoru
authors.initials: M
authors.lastname: Fujitsuka
authors.affiliation: The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047 (Japan), Fax: (+81) 6-6879-8499. majima@sanken.osaka-u.ac.jp.
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Majima
mesh_terms: D000114:Acetylene / Q000031:analogs & derivatives* / Q000737:chemistry; D000225:Adenine / Q000737:chemistry*; D004247:DNA / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism; D004249:DNA Damage; D004260:DNA Repair; D004579:Electron Transport; D004583:Electrons; D009711:Nucleotides / Q000737:chemistry* / Q000378:metabolism; D017319:Photosensitizing Agents / Q000737:chemistry*; D013876:Thiophenes / Q000737:chemistry*; D013941:Thymine / Q000737:chemistry*
chemical_list: D009711:Nucleotides; D017319:Photosensitizing Agents; D013876:Thiophenes; C044735:biphenylacetylene; D004247:DNA; D000225:Adenine; D000114:Acetylene; D013941:Thymine
keywords: DNA; electron transfer; electronic coupling; laser flash photolysis; photochemistry