PHOTOINDUCED DEOXYRIBOSE-C2' OXIDATION IN DNA - ALKALI-DEPENDENT CLEAVAGE OF ERYTHROSE-CONTAINING SITES VIA A RETROALDOL REACTION
PHOTOINDUCED DEOXYRIBOSE-C2' OXIDATION IN DNA - ALKALI-DEPENDENT CLEAVAGE OF ERYTHROSE-CONTAINING SITES VIA A RETROALDOL REACTION
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DOI：
10.1021/ja00064a004
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发表时间：
1993-06-02
影响因子：
15
通讯作者：
SAITO, I
中科院分区：
文献类型：
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作者：
SUGIYAMA, H;TSUTSUMI, Y;SAITO, I
已研究了各种含 5-碘尿嘧啶-((I)U) 寡核苷酸的光反应。结果发现，d(GCA(I)UGC)2 在 (I)U 残基的 5' 侧经历竞争性 C1' 和 C2' 氧化，分别产生含脱氧核糖内酯的六聚体 1 和含赤藓糖的六聚体 2。在碱性条件下搅拌后，含赤藓糖的六聚体 2 经历了非常容易的逆羟醛反应，以高产率产生两个片段，两者都具有磷酸糖醛末端。基于2的化学反应性，设计了一种新的特异性检测DNA中脱氧核糖C2'氧化产生的含赤藓糖位点的方法。通过光照射含双链体 (I)U 的 13 mer 5'-d(CG(I)UGT(I)UTA(I)UAC(I)UG)-3'/5'-d(CAGTATAAACACG)-3' 来制备含赤藓糖的位点。光照射后，将反应混合物用热碱和NaBH 4 处理，然后进行酶消化。消化混合物的 HPLC 分析揭示了修饰单核苷酸 25-28 的形成，从而可以对 13 聚体的所有四个 (I)U 残基的 5' 侧产生的含赤藓糖位点进行定量。这些结果表明该方法可用于检测和定量 DNA 中脱氧核糖 C2' 氧化产生的含赤藓糖位点。
Photoreactions of various 5-iodouracil-((I)U)-containing oligonucleotides have been investigated. It was found that d(GCA(I)UGC)2 undergoes a competitive C1' and C2' oxidation at the 5' side of the (I)U residue to give deoxyribonolactone-containing hexamer 1 and erythrose-containing hexamer 2, respectively. Upon beating under alkaline conditions, erythrose-containing hexamer 2 was shown to undergo a remarkably facile retroaldol reaction to give two fragments, both having phosphoroglycoaldehyde termini in high yields. On the basis of the chemical reactivity of 2, a new specific method for detection of the erythrose-containing sites resulting from deoxyribose C2' oxidation in DNA was devised. Erythrose-containing sites were prepared by photoirradiation of duplex (I)U-containing 13 mer 5'-d(CG(I)UGT(I)UTA(I)UAC(I)UG)-3'/5'-d(CAGTATAAACACG)-3'. After photoirradiation, the reaction mixture was treated with hot alkali and NaBH4 and then subjected to enzymatic digestion. HPLC analysis of the digested mixture revealed the formation of modified mononucleotides 25-28, allowing the quantification of the erythrose-containing sites being produced at the 5' side of all four (I)U residues of the 13 mer. These results indicate that this method can be used for the detection and quantification of erythrose-containing sites resulting from deoxyribose C2' oxidation in DNA.