Long-distance radical cation transport in DNA: Horizontal charge hopping in a dimeric quadruplex.
A series of DNA hairpins were synthesized and shown to associate to form quadruplexes formed by stacking five G-quartets in an antiparallel orientation. One of the hairpins in the quadruplex was linked covalently at the 5'-end to an anthraquinone (AQ) group and a 32P label was incorporated either at the 3'-terminus of the AQ-containing hairpin or on its partner hairpin in the quadruplex. Irradiation of the AQ group with UV light leads to the one-electron oxidation of the DNA and concomitant introduction of a radical cation into the DNA. Analysis by PAGE and autoradiography shows that the radical cation reacts at guanines both on the AQ-containing strand and with its partner hairpin in the quadruplex. This observation demonstrates that charge migration in DNA occurs vertically along a DNA chain and horizontally within a G-quartet.
Ndlebe
Thabisile
T
School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA.
Schuster
Gary B
GB
D001483:Base Sequence; D002021:Buffers; D002412:Cations / Q000737:chemistry*; D004247:DNA / Q000737:chemistry* / Q000235:genetics; D003850:Deoxyribonuclease I / Q000378:metabolism; D019281:Dimerization; D031541:Fluorescence Resonance Energy Transfer; D054856:G-Quadruplexes; D008745:Methylation; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D055672:Static Electricity
D002021:Buffers; D002412:Cations; D004247:DNA; D003850:Deoxyribonuclease I