Distance dependence of electron transfer in acridine-intercalated DNA

Keijiro Fukui, Kazuyoshi Tanaka, Mamoru Fujitsuka, Akira Watanabe, Osamu Ito

    研究成果: Article査読

    76 被引用数 (Scopus)

    抄録

    The photoinduced electron-transfer reaction in a DNA helix has been studied using 9-amino-6-chloro-2-methoxyacridine (ACMA) selectively intercalated at an internucleotide site of a DNA. The photoexcited ACMA is used as an electron acceptor, and guanine in DNA as an electron donor. ACMA-DNA conjugates possessing guanine at 5' or 3' direction(s) with different distance(s) from the intercalated ACMA have been prepared for a systematic examination of the distance dependence of the electron-transfer reaction in a DNA helix. In DNA consisting of only the (dA-dT) base pair, the fluorescence of the singlet-excited ACMA decays in a mono-exponential manner with a longest lifetime of 22.8 ns. The fluorescence lifetime of the excited ACMA decreases with incorporation of guanosine depending on the distance between the ACMA and guanine. When an ACMA and a guanine are directly stacked, the decay lifetime markedly decreases, showing a forward electron-transfer rate, k(fet), of ≃ 1010 s-1. Treating the kinetic data according to k(fet) = Aexp (- βR), where R is the separation distance in Å, gives a β value of 1.47 Å-1. Moreover, as a model compound for ACMA, the redox potential of quinacrine dihydrate bi (tetrafluoroborate) has been measured by cyclic voltammetry in acetonitrile. Comparison of the redox potential with those of nucleobases has revealed that only guanine can quench the fluorescence of ACMA and a free-energy change ΔG°= -0.46 eV has been evaluated for this electron-transfer reaction.

    本文言語English
    ページ(範囲)18-27
    ページ数10
    ジャーナルJournal of Photochemistry and Photobiology B: Biology
    50
    1
    DOI
    出版ステータスPublished - 1999 5月 1

    ASJC Scopus subject areas

    • 放射線
    • 放射線技術および超音波技術
    • 生物理学
    • 放射線学、核医学およびイメージング

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