Optimization of fluorescence property of the 8-oxodGclamp derivative for better selectivity for 8-oxo-2′-deoxyguanosine
作者:Yohei Koga、Yasufumi Fuchi、Osamu Nakagawa、Shigeki Sasaki
DOI:10.1016/j.tet.2011.03.111
日期:2011.9
2'-Deoxyguanosine (dG) suffers from oxidation by reactive oxygen species (ROS) to form 8-oxo-2'-deoxyguanosine (8-oxo-dG), which is regarded as a marker of oxidative stress in the cells. In our continuous study for the recognition molecule of 8-oxo-dG, 8-oxoGclamp and its derivatives have been identified as the selective fluorescent probe. However, it is an obstacle for further application that dG also forms a complex with 8-oxoGclamp. resulting in fluorescence quenching in less polar solvents. Quenching of the fluorescence of 8-oxoGclamp is thought to involve photo-induced electron transfer in the complex. It was hypothesized that the energy level of the excited state of 8-oxoGclamp and the HOMO energy of dG are the preliminary determinant of the quenching efficiency. Thus, fluorescence properties of the substituted derivatives at the 7-position of the 1,3-diazaphenoxazine part of 8-oxoGclamp were investigated. Among the new derivatives, fluorescence of the 7-phenyl substituted 8-oxoGclamp was not quenched by dG even in the stable complex, exhibiting the highest selectivity for 8-oxo-dG. (C) 2011 Elsevier Ltd. All rights reserved.