Reaction of Hydrated Electrons with Guanine Derivatives: Tautomerism of Intermediate Species

被引：12

作者：

D'Angelantonio, Mila ^{[1
]}

Russo, Marialuisa ^{[1
,2
]}

Kaloudis, Panagiotis ^{[1
]}

Mulazzani, Quinto G. ^{[1
]}

Wardman, Peter ^{[2
]}

Guerra, Maurizio ^{[1
]}

Chatgilialoglu, Chryssostomos ^{[1
]}

机构：

[1] CNR, ISOF, I-40129 Bologna, Italy

[2] Univ Oxford, Mt Vernon Hosp, Gray Canc Inst, Northwood HA6 2JR, Middx, England

来源：

JOURNAL OF PHYSICAL CHEMISTRY B | 2009年 / 113卷 / 07期

关键词：

AQUEOUS-SOLUTION; RADICALS; DNA; NUCLEOSIDES; THERMOCHEMISTRY; MODELS;

D O I：

10.1021/jp809386c

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Here, we show that two tautomers are produced by the protonation of the guanine-electron adduct. The fate of electron adducts of a variety of substituted guanosines was investigated by radiolytic methods and addressed computationally by means of time-dependent DFT (TD-B3LYP/6-311G**//B1B95/6-31+G**) calculations. The reaction of e(aq)(-) with guanosine and 1-methylguanosine produces two transient species, whereas the reaction with N-2-ethylguanosine and N-2,N-2-diethylguanosine produces only one. The two short-lived intermediates, which show a substantial difference in their UV-visible spectra, are recognized to be two purine tautomers (i.e., iminic 18 and aminic 19 forms). The tautomerization 18 -> 19 occurs with a rate constant of ca. 1.5 x 10(6) s(-1), and theory suggests that it is a water-assisted process.

引用

页码：2170 / 2176

页数：7

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