Site specific synthesis and polymerase bypass of oligonucleotides containing a 6-hydroxy-3,5,6,7-tetrahydro-9H-imidazo[1,2-α]purin-9-one base, an intermediate in the formation of 1,N2-etheno-2'-deoxyguanosine
Site specific synthesis and polymerase bypass of oligonucleotides containing a 6-hydroxy-3,5,6,7-tetrahydro-9H-imidazo[1,2-α]purin-9-one base, an intermediate in the formation of 1,N2-etheno-2'-deoxyguanosine
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DOI：
10.1021/tx050141k
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发表时间：
2005-11-01
影响因子：
4.1
通讯作者：
Rizzo, CJ
中科院分区：
文献类型：
--
作者：
Goodenough, AK;Kozekov, ID;Rizzo, CJ
DNA 与某些双亲电子试剂（如氯环氧乙烷和氯乙醛）反应生成乙烯加合物。这些病变是高度错误编码的，并且产生它们的一些化学制剂已被证明对实验动物和人类具有致癌性。形成 1,N-2-乙烯鸟嘌呤的中间体是 6-羟基-3,5,6,7四氢-9H-咪唑并[1,2-a]嘌呤-9-酮（6-羟基乙烯鸟嘌呤），它会转化为乙烯加合物。羟基乙醇加合物的化学性质和误编码可能性此前尚未研究过。开发了羟基乙醇加合核苷的合成方法，并将其位点特异性地掺入寡核苷酸中。在中性 pH 值和 25 摄氏度下，该加合物的核苷和寡核苷酸水平的半衰期为 24 至 48 小时。通过使用 DNA 聚合酶 Dpo4 和 pol T7(-) 进行引物延伸反应来检查羟基乙醇加合物的错误编码可能性，并将结果与相应的乙烯加合物寡核苷酸进行比较。 Dpo4优先掺入与羟基乙醇加合物相反的dATP和与乙烯加合物相反的dGTP； pol T7-优先在乙烯加合物对面掺入dATP，而dGTP和dATP在羟基乙醇加合物对面掺入，催化效率几乎相同。总的来说，这些结果表明羟基乙醇加合物具有足够的寿命和错误编码特性，有助于氯环氧乙烷和相关基因毒性物质的诱变谱。
The reaction of DNA with certain bis-electrophiles such as chlorooxirane and chloroacetaldehyde produces etheno adducts. These lesions are highly miscoding, and some of the chemical agents that produce them have been shown to be carcinogenic in laboratory animals and in humans. An intermediate in the formation of 1,N-2-ethenoguanine is 6-hydroxy-3,5,6,7tetrahydro-9H-imidazo[1,2-a]purin-9-one (6-hydroxyethanoguanine), which undergoes conversion to the etheno adduct. The chemical properties and miscoding potential of the hydroxyethano adduct have not been previously studied. A synthesis of the hydroxyethano-adducted nucleoside was developed, and it was site specifically incorporated into oligonucleotides. This adduct had a half-life of between 24 and 48 h at neutral pH and 25 degrees C at the nucleoside and oligonucleotide levels. The miscoding potential of the hydroxyethano adduct was examined by primer extension reactions with the DNA polymerases Dpo4 and pol T7(-), and the results were compared to the corresponding etheno-adducted oligonucleotide. Dpo4 preferentially incorporated dATP opposite the hydroxyethano adduct and dGTP opposite the etheno adduct; pol T7- preferentially incorporated dATP opposite the etheno adduct while dGTP and dATP were incorporated opposite the hydroxyethano adduct with nearly equal catalytic efficiencies. Collectively, these results indicate that the hydroxyethano adduct has a sufficient lifetime and miscoding properties to contribute to the mutagenic spectrum of chlorooxirane and related genotoxic species.