Electron transfer vs. proton transfer within radical-cation clusters of guanosine and deoxyguanosine with substituted naphthalenes and sinapinic acid

Guanosine (G) and deoxyguanosine (dG) radical cations can be generated in t he gas phase by single electron transfer (SET) within nucleoside-dimethoxyn aphthalenes (1-2) electron-bound heterodimers produced by fast atom bombard ment in a four sector mass spectrometer. The nucleobase guanine is much mor e easily oxidized when it is linked to a ribose moiety. The radical cation dimers formed by G and dG with sinapinic acid behave as proton-bound hetero dimers. The experiments mimic to some extent the migration of radical sites within stacking bases which causes DNA damaging through depurination proce sses. (C) 2001 American Society for Mass Spectrometry.