Department of Chemistry, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA.
Chembiochem. 2012 Jun 18;13(9):1338-48. doi: 10.1002/cbic.201200139. Epub 2012 May 25.
Thymine glycol (Tg), one of the oxidized bases formed in DNA by reactive oxygen species, is repaired by the DNA glycosylases such as NEIL1, NTH1 and Endo III. In our recent studies, we showed that NEIL1's catalytic efficiency and lesion specificity are regulated by an RNA-editing adenosine deamination reaction. In this study, we synthesized oligodeoxynucleotides containing 2'-fluorothymidine glycol with either ribo or arabino configuration and investigated the binding of these modified DNAs with the unedited and edited forms of human NEIL1 along with E. coli Endo III. For the two forms of hNEIL1, binding affinities to FTg-containing DNA were similar indicating that the editing effect is more subtle than to simply alter substrate affinity. While the NEIL1-binding to FTg-containing DNAs was largely insensitive to C5 and 2' stereochemistry, a preference was observed for the FTg-G pair over the FTg-A pair. In addition, we found that optimal binding is observed with Endo III and duplex DNA with riboFTg(5S) paired with dG. The modified DNAs reported here will provide useful tools for further characterizing the interaction between DNA repair glycosylases and thymine glycol containing DNA.
胸腺嘧啶乙二醇（Tg）是活性氧物种在 DNA 中形成的氧化碱基之一，由 DNA 糖苷酶如 NEIL1、NTH1 和内切 III 修复。在我们最近的研究中，我们表明 NEIL1 的催化效率和损伤特异性受 RNA 编辑腺苷脱氨酶反应调节。在这项研究中，我们合成了含有 2'-氟胸腺嘧啶乙二醇的寡脱氧核苷酸，具有核糖或阿拉伯糖构型，并研究了这些修饰的 DNA 与未经编辑和编辑形式的人 NEIL1 以及大肠杆菌内切 III 的结合。对于两种形式的 hNEIL1，与含 FTg 的 DNA 的结合亲和力相似，表明编辑效应比简单改变底物亲和力更微妙。虽然 NEIL1 与含 FTg 的 DNA 的结合对 C5 和 2'立体化学基本不敏感，但观察到 FTg-G 对与 FTg-A 对的偏好。此外，我们发现与内切 III 和具有核糖 FTg(5S)与 dG 配对的双链 DNA 的最佳结合。这里报道的修饰 DNA 将为进一步表征 DNA 修复糖苷酶与含胸腺嘧啶乙二醇的 DNA 之间的相互作用提供有用的工具。
