Direct effect of heavy ions and electrons on 2′-deoxyguanosine in the solid state
作者:Marina Gromova、Robert Nardin、Jean Cadet
DOI:10.1039/a801069b
日期:——
Attempts have been made in this work to gain insights into the mechanisms of the formation of degradation products arising from the exposure of 2â²-deoxyguanosine (dGuo) in the solid state to O7+ heavy ions of 10.6 MeV uâ1 (LET â 500 keV µmâ1). 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 2â²-deoxyguanosine with those produced by lower LET radiation. For this purpose, the samples of 2â²-deoxyguanosine were exposed in the solid state to electrons of 2 MeV (LET â 0.18 keV µmâ1). 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.
本研究尝试深入了解在固态下,2'-脱氧鸟苷(dGuo)暴露于10.6 MeV u⁻¹的O7+重离子(LET ≈ 500 keV µm⁻¹)时所生成降解产物的形成机制。通过反相高效液相色谱法分离了dGuo的主要分解产物,并通过广泛的光谱测量(¹H和¹³C NMR、质谱、紫外光谱)对其进行了表征。提出了涉及糖和嘌呤自由基瞬时形成的反应机制,以解释重离子介导的降解产物的生成。本研究的另一个主要目标是比较重离子诱导的2'-脱氧鸟苷的修饰与低LET辐射所产生的修饰。为此,2'-脱氧鸟苷样品在固态下暴露于2 MeV的电子(LET ≈ 0.18 keV µm⁻¹)。通过定性和半定量比较的结果可推断,重离子对糖部分的修饰诱导效率高于电子。