title: Kinetics of weak distance-dependent hole transfer in DNA by adenine-hopping mechanism.
abstract: The kinetics of hole transfer in DNA by adenine-hopping mechanism was investigated by the combined pulse radiolysis-laser flash photolysis method. The hole transfer from Ptz*+* to oxG across the (A)n-bridge preceded by the A-hopping mechanism and the weak distance-dependent hole transfer with the rates faster than 108 s-1 over the distance range of 7-22 A was demonstrated. In contrast, hole transfer from oxG*+ to Ptz followed the single-step super exchange mechanism. Thus, two different processes for the hole transfer across the identical (A)n-bridge in DNA have been demonstrated. The results clearly show that the mechanism of hole transfer in DNA strongly depends on the redox nature of the oxidant, whether it produces only G*+ or both A*+ and G*+.
authors.affiliation: The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan. kiyohiko@sanken.osaka-u.ac.jp
authors.forename: Kiyohiko
authors.initials: K
authors.lastname: Kawai
authors.forename: Tadao
authors.initials: T
authors.lastname: Takada
authors.forename: Sachiko
authors.initials: S
authors.lastname: Tojo
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Majima
mesh_terms: D000225:Adenine / Q000737:chemistry*; D004247:DNA / Q000737:chemistry*; D007700:Kinetics; D009841:Oligonucleotides / Q000737:chemistry; D010640:Phenothiazines / Q000737:chemistry; D010782:Photolysis; D011675:Pulse Radiolysis
chemical_list: D009841:Oligonucleotides; D010640:Phenothiazines; D004247:DNA; D000225:Adenine