Direct effect of heavy ions and electrons on 2′-deoxyguanosine in the solid state
Abstract
Attempts have been made in this work to gain insights into the mechanisms of the formation of degradation products arising from the exposure of 2′-deoxyguanosine (dGuo) in the solid state to O7+ heavy ions of 10.6 MeV u–1 (LET ≈ 500 keV µm–1). The main decomposition products of dGuo have been isolated by reversed-phase high performance liquid chromatography and characterized by extensive spectroscopic (1H and 13C NMR, mass spectrometry, UV) measurements. Reaction mechanisms, involving the transient formation of sugar and purine radical, are proposed to explain the generation of the heavy ion-mediated degradation products. Another major objective of the present work is the comparison of heavy ion-induced modifications of 2′-deoxyguanosine with those produced by lower LET radiation. For this purpose, the samples of 2′-deoxyguanosine were exposed in the solid state to electrons of 2 MeV (LET ≈ 0.18 keV µm–1). It may be inferred from the results of the qualitative and semi-quantitative comparison that the modifications of the sugar moiety are more efficiently induced by heavy ions than by electrons.