Concerning the Hydrolytic Stability of 8-Aryl-2′-deoxyguanosine Nucleoside Adducts: Implications for Abasic Site Formation at Physiological pH
作者:Katherine M. Schlitt、Ke-wen M. Sun、Robert J. Paugh、Andrea L. Millen、Lex Navarro-Whyte、Stacey D. Wetmore、Richard A. Manderville
DOI:10.1021/jo901080w
日期:2009.8.21
Direct addition of aryl radical species to the C8-site of 2′-deoxyguanosine (dG) affords C8-aryl-dG adducts that are produced by carcinogenic arylhydrazines, polycyclic aromatic hydrocarbons (PAHs), and certain phenolic toxins. A common property of C8-arylpurine adduction is the accompaniment of abasic site formation. To determine how the C8-aryl moiety contributes to sugar loss, UV−vis spectroscopy
将芳基自由基种直接加到2'-脱氧鸟苷(dG)的C 8位上可得到C 8-芳基-dG加合物,其由致癌的芳基肼,多环芳烃(PAH)和某些酚类毒素产生。C 8-芳基嘌呤加合的共同性质是无碱基位点形成的伴随。为了确定C 8-芳基部分如何导致糖损失,已使用紫外可见光谱法确定N 7 p K a1值和水解动力学,同时利用密度泛函理论(DFT)计算来探究结构特征和C 8的稳定性带有不同对和邻取代基的-芳基-dG加合物。在所有情况下,将C 8 -芳基-dG加合物采取顺含有强ø构象5 '-H···Ñ 3氢与相对于所述核碱基扭曲芳环键。该加合物经历Ñ 7 -protonation与电离常数和n计算7质子亲和力(PA)值类似于用于dG的测量。水解动力学表明,C 8-芳基-dG核苷加合物比dG更易于酸催化水解,其中带有对位取代基的k 1值为ca。比k 1大90至200倍对于dG,对原加合物的作用仅约。大9至60倍。通