COMPARISON OF BISULFITE MODIFICATION OF 5-METHYLDEOXYCYTIDINE AND DEOXYCYTIDINE RESIDUES
COMPARISON OF BISULFITE MODIFICATION OF 5-METHYLDEOXYCYTIDINE AND DEOXYCYTIDINE RESIDUES
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DOI：
10.1093/nar/8.20.4777
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发表时间：
1980-01-01
影响因子：
14.9
通讯作者：
EHRLICH, M
中科院分区：
文献类型：
--
作者：
WANG, RYH;GEHRKE, CW;EHRLICH, M
亚硫酸氢钠是一种诱变剂，可通过形成5，6-二氢胞嘧啶-6-磺酸中间体特异性地将单链DNA中超过96%的胞嘧啶残基脱氨基。在相同的反应条件下，具有34摩尔% m5 Cyt的单链XP-12 DNA中仅2-3%的5-甲基胞嘧啶（m5 Cyt）残基转化为胸腺嘧啶（Thy）残基。相比之下，在脱氧核苷和游离碱水平下，用亚硫酸氢盐然后用碱进行的相同处理分别将51%和> 95%的m5 Cyt转化为相应的Thy衍生物。然而，m5 Cyt及其脱氧核糖核苷的反应速率比胞嘧啶或脱氧胞苷分别定量转化为尿嘧啶或脱氧尿苷的类似反应速率慢得多。与未甲基化的类似物相比，m5 Cyt及其衍生物的低得多的反应性主要是由于磺酸盐加合物形成速率的降低。
Sodium bisulfite is a mutagen which can specifically deaminate more than 96% of the cytosine residues in single-stranded DNA via formation of a 5,6-dihydrocytosine-6-sulfonate intermediate. Under the same reaction conditions, only 2–3% of the 5-methylcytosine (m5Cyt) residues in single-stranded XP-12 DNA, which has 34 mole% m5Cyt was converted to thymine (Thy) residues. In contrast, at the deoxynucleoside and free base levels, the same treatment with bisulfite and then alkali converted 51% and > 95%, respectively, of the m5Cyt to the corresponding Thy derivatives. However, the rate of reaction of m5Cyt and its deoxyribonucleoside was much slower than that of the analogous quantitative conversion of cytosine or deoxycytidine to uracil or deoxyuridine, respectively. The much lower reactivity of m5Cyt and its derivatives compared to that of the unmethylated analogs is primarily due to a decrease in the rate of formation of the sulfonate adduct.