Photosensitized one-electron oxidation of DNA*
Kiyohiko Kawai and Tetsuro Majima
The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
Abstract: Photosensitized one-electron oxidation of DNA has attracted much interest because it causes oxidative damage which leads to mutation, and because it is involved in the basic mechanism of photodynamic therapy. In the present article, we describe the mechanistic study of photosensitized DNA damage, especially addressing the kinetics of hole transfer by adenine(A)-hopping and its effect on the DNA damage. The combination of the transient absorption measurement and DNA damage quantification by high-performance liquid chromatography clearly demonstrate that the yield of the DNA damage correlates well with the lifetime of the charge-separated state caused by A-hopping, showing that hole transfer helps DNA damage. These findings led us to propose a new method to accomplish the efficient DNA damage using a combination of two-color, two-laser irradiation.
Keywords: DNA; DNA damage; one-electron oxidation; photosensitized oxidation; hole transfer in DNA; charge-separated state; two-color, two-laser irradiation; photosensitized electron transfer.
*Paper based on a presentation at the XXth IUPAC Symposium on Photochemistry, Granada, Spain, 17-22 July 2004. Other presentations are published in this issue, pp. 925-1085.