Locating the uracil-5-yl radical formed upon photoirradiation of 5-bromouracil-substituted DNA.
Locating the uracil-5-yl radical formed upon photoirradiation of 5-bromouracil-substituted DNA.
复制标题
DOI：
10.1093/nar/gku1133
复制
发表时间：
2014-12-16
影响因子：
14.9
通讯作者：
Sugiyama H
中科院分区：
文献类型：
--
作者：
Hashiya F;Saha A;Kizaki S;Li Y;Sugiyama H
在之前的研究中，我们发现在特定的5-溴尿嘧啶（BrU）取代序列5′-（G/C）[A]n = 1,2BrUBrU-3′中有效生成2-脱氧核糖内酯，并提出在302 nm照射条件下形成的尿嘧啶-5-基自由基主要从BrUBrU的5′侧提取C1′氢。在目前的工作中，我们在氢供体四氢呋喃存在下对 BrU 取代的 DNA 进行光照射，以将尿嘧啶-5-基自由基淬灭为尿嘧啶，然后对样品进行尿嘧啶 DNA 糖基化酶消化。平板凝胶序列分析表明，BrU 取代 DNA 在 302 nm 照射下，在 5'-(G/C)[A]n = 1,2BrUBrU-3' 热点序列处形成尿嘧啶残基。此外，我们发现尿嘧啶残基也在反向序列5'-BrUBrU[A]n = 1,2(G/C)-3'处形成，这表明5'-(G/C)[A]n = 1,2BrUBrU-3'和5'-BrUBrU[A]n = 1,2(G/C)-3'都是形成尿嘧啶-5-基的热点序列。激进的。
In a previous study, we found that 2-deoxyribonolactone is effectively generated in the specific 5-bromouracil (BrU)-substituted sequence 5′-(G/C)[A]n = 1,2BrUBrU-3′ and proposed that a formed uracil-5-yl radical mainly abstracts the C1′ hydrogen from the 5′-side of BrUBrU under 302-nm irradiation condition. In the present work, we performed photoirradiation of BrU-substituted DNA in the presence of a hydrogen donor, tetrahydrofuran, to quench the uracil-5-yl radical to uracil and then subjected the sample to uracil DNA glycosylase digestion. Slab gel sequence analysis indicated that uracil residues were formed at the hot-spot sequence of 5′-(G/C)[A]n = 1,2BrUBrU-3′ in 302-nm irradiation of BrU-substituted DNA. Furthermore, we found that the uracil residue was also formed at the reverse sequence 5′-BrUBrU[A]n = 1,2(G/C)-3′, which suggests that both 5′-(G/C)[A]n = 1,2BrUBrU-3′ and 5′-BrUBrU[A]n = 1,2(G/C)-3′ are hot-spot sequences for the formation of the uracil-5-yl radical.