Tsunoda Hirosuke, Ohkubo Akihiro, Seio Kohji, Sekine Mitsuo
Department of Life Science, Tokyo Institute of Technology, Yokohama 226-8501, Japan.
Nucleic Acids Symp Ser (Oxf). 2009(53):127-8. doi: 10.1093/nass/nrp064.
The main products obtained by oxidation of cytosine and adenine bases with hydrogen peroxide are cytosine and adenine N-oxide derivatives. There is a possibility that these N-oxide derivatives are mutagenic in genomic DNA like 8-oxoguanine or thymine glycol. Although the chemical synthesis and properties of 2'-deoxynucleoside N-oxide derivatives have been well established, little has been reported about the chemical and biochemical behavior of oligodeoxynucleotides (ODNs) containing these modified 2'-deoxynucleoside. In this study, we examined their base recognition ability by DNA polymerase reactions. It was found that these modified derivatives were incorporated into the 3'-terminal site of an ODN by DNA polymerase selecting accurately the complementary G or T base on a template ODN. In the incorporation reaction using template ODNs containing 2'-deoxynucleoside N-oxide bases, their N-oxide bases were selectively recognized by the complementary 5'-triphosphate (dGTP or dTTP).
用过氧化氢氧化胞嘧啶和腺嘌呤碱基得到的主要产物是胞嘧啶和腺嘌呤N-氧化物衍生物。这些N-氧化物衍生物有可能像8-氧代鸟嘌呤或胸腺嘧啶二醇一样在基因组DNA中具有致突变性。尽管2'-脱氧核苷N-氧化物衍生物的化学合成和性质已经得到充分证实，但关于含有这些修饰的2'-脱氧核苷的寡脱氧核苷酸（ODN）的化学和生化行为报道很少。在本研究中，我们通过DNA聚合酶反应检测了它们的碱基识别能力。结果发现，这些修饰的衍生物通过DNA聚合酶准确地选择模板ODN上互补的G或T碱基，被掺入到ODN的3'-末端位点。在使用含有2'-脱氧核苷N-氧化物碱基的模板ODN的掺入反应中，它们的N-氧化物碱基被互补的5'-三磷酸（dGTP或dTTP）选择性识别。
