Strand breakage of a (6-4) photoproduct-containing DNA at neutral pH and its repair by the ERCC1-XPF protein complex
Strand breakage of a (6-4) photoproduct-containing DNA at neutral pH and its repair by the ERCC1-XPF protein complex
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DOI：
10.1039/c3ob00012e
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发表时间：
2013-01-01
影响因子：
3.2
通讯作者：
Iwai, Shigenori
中科院分区：
文献类型：
--
作者：
Arichi, Norihito;Yamamoto, Junpei;Iwai, Shigenori
（6-4）光产物是紫外线引起的DNA损伤的主要产物之一。我们以前表明，水解开环的5'碱和随后的水解的糖苷键的3'组件发生时，这种光产物用NaOH水溶液处理。在本研究中，我们发现，当（6-4）光产物在用乙酸调节至pH 7.4的0.1 M N，N '-二甲基-1，2-乙二胺溶液中于90 ℃加热6 h时，得到另一种产物。该产物的化学结构分析表明，5'碱基是完整的，而3'组分的糖苷键以相同的方式水解。在用上述溶液或含有生物胺如亚精胺和精胺的其它pH 7.4溶液处理时，检测到含有（6-4）光产物的30-mer寡核苷酸的链断裂。在亚精胺的情况下，在37 ℃下计算出的速率常数为1.4 × 10（-8）s（-1）。即使当寡核苷酸在0.1M磷酸钠（pH 7.0）中于90 ℃加热时也发生链断裂，尽管这种处理产生了几种类型的5 ′片段。杜瓦化合价异构体对该反应是惰性的。从含有（6-4）光产物的30-mer获得的产物用于研究带有受损碱基和磷酸的3'端的酶加工。在复制蛋白A存在的情况下，ERCC 1-XPF复合物去除了含有受损碱基的几个核苷酸。
The (6-4) photoproduct is one of the major UV-induced lesions in DNA. We previously showed that hydrolytic ring opening of the 5' base and subsequent hydrolysis of the glycosidic bond of the 3' component occurred when this photoproduct was treated with aqueous NaOH. In this study, we found that another product was obtained when the (6-4) photoproduct was heated at 90 degrees C for 6 h, in a 0.1 M solution of N,N'-dimethyl-1,2-ethanediamine adjusted to pH 7.4 with acetic acid. An analysis of the chemical structure of this product revealed that the 5' base was intact, whereas the glycosidic bond at the 3' component was hydrolyzed in the same manner. The strand break was detected for a 30-mer oligonucleotide containing the (6-4) photoproduct upon treatment with the above solution or other pH 7.4 solutions containing biogenic amines, such as spermidine and spermine. In the case of spermidine, the rate constant was calculated to be 1.4 x 10(-8) s(-1) at 37 degrees C. The strand break occurred even when the oligonucleotide was heated at 90 degrees C in 0.1 M sodium phosphate (pH 7.0), although this treatment produced several types of 5' fragments. The Dewar valence isomer was inert to this reaction. The product obtained from the (6-4) photoproduct-containing 30-mer was used to investigate the enzymatic processing of the 3' end bearing the damaged base and a phosphate. The ERCC1-XPF complex removed several nucleotides containing the damaged base, in the presence of replication protein A.