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DNA腺嘌呤阳离子自由基脱质子反应机理的研究
节家龙,王琛,赵红梅,宋迪*,苏红梅*
作者单位E-mail
节家龙 中国科学院化学研究所, 北京 100190;中国科学院大学, 北京 100049  
王琛 北京师范大学, 北京 100875  
赵红梅 中国科学院化学研究所, 北京 100190  
宋迪* 中国科学院化学研究所, 北京 100190 songdi@iccas.ac.cn 
苏红梅* 中国科学院化学研究所, 北京 100190;北京师范大学, 北京 100875 hongmei@bnu.edu.cn 
摘要:
关键词:  
DOI:10.1063/1674-0068/30/cjcp1710198
分类号:
基金项目:This work was supported by the National Natural Science Foundation of China (No.21425313, No.21333012, No.21373233, and No.91441108) and the Chinese Academy of Sciences (No.XDB12020200).
Experimental and Theoretical Study of Deprotonation of DNA Adenine Cation Radical
Jia-long Jie,Chen Wang,Hong-mei Zhao,Di Song*,Hong-mei Su*
Abstract:
Among all the DNA components, extremely redox-active guanine (G) and adenine (A) bases are subject to facile loss of an electron and form cation radicals (G and A) when exposed to irradiation or radical oxidants. The subsequent deprotonation of G and A can invoke DNA damage or interrupt hole transfer in DNA. However, compared with intensive reports for G, studies on the deprotonation of A are still limited at present. Herein, we investigate the deprotonation behavior of A by time-resolved laser flash photolysis. The deprotonation product of A(N6-H)· is observed and the deprotonation rate constant, (2.0±0.1)×107 s-1, is obtained at room temperature. Further, the deprotonation rate constants of A are measured at temperatures varying from 280 K to 300 K, from which the activation energy for the N6-H deprotonation is determined to be (17.1±1.0) kJ/mol by Arrhenius equation. In addition, by incorporating the aqueous solvent effect, we perform density functional theory calculations for A deprotonation in free base and in duplex DNA. Together with experimental results, the deprotonation mechanisms of A in free base and in duplex DNA are revealed, which are of fundamental importance for understanding the oxidative DNA damage and designing DNA-based electrochemical devices.
Key words:  DNA adenine  Deprotonation rate constant  Activation energy barrier  Density functional theory calculation