气相中碱基与核苷自由基的产生与结构研究

Production and Structure Study of Free Radicals of Bases and Nucleosides in Gas Phase

核苷自由基在生物体内扮演着关键角色,特别是在DNA损伤过程中。为深入研究这些自由基的性质、反应机制以及与其他生物分子的相互作用,确定其结构至关重要。质谱通过提供高真空环境,为自由基离子创造了惰性的研究环境,在核苷自由基和碱基自由基的气相研究中展示了不可替代的作用。此外,结合串联质谱和理论计算,能够更准确地分析自由基结构。本文总结了近20年来基于质谱技术的气相中碱基与核苷自由基的研究,详细介绍了自由基离子的产生方法、研究手段以及结构分析的最新成果,提出了对于高活性自由基中间体的结构研究,以及自由基异构体的选择性产生仍然面临挑战,亟需发展新的实验方法和技术手段。

Nucleoside free radicals have important functions in organisms and play a crucial role in DNA damage.Accurately understanding the structure of nucleoside free radicals is crucial for studying their properties,reaction mechanisms,and interactions with other biomolecules.The high vacuum in the mass spectrometer provides an inert environment for free radicals.Further tandem mass spectrometry combined with theoretical calculation is crucial for achieving their structural informations.This article reviewed gas phase studies of base and nucleoside radicals based on mass spectrometry in the past two decades,and provided a detailed introduction and comparison of their production methods,structural research methods and progress.Different methods were developed for the generation of the free radical ions,including collision induced dissociation of precursor ions of ternary transition metal complexes or those introducing free radical initiators,electron transfer dissociation of precursor ions charge-tagged,and UV photodissociation of precursor ions including C—I bonds.Besides,the methods for studying the structure of free radical ions in gas phase have gradually enriched,including commonly used tandem mass spectrometry,UV-visible and IR photodissociation spectroscopy.Based on the above methods,many different base and nucleoside free radical ions were generated and structurally determined in gas phase.On the other hand,the research of the highly active free radical intermediates and the selective generation of free radical isomers still pose challenges,and there is an urgent need to develop new experimental method.