X-RAY STRUCTURE OF A DNA DECAMER CONTAINING 7,8-DIHYDRO-8-OXOGUANINE
X-RAY STRUCTURE OF A DNA DECAMER CONTAINING 7,8-DIHYDRO-8-OXOGUANINE
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DOI：
10.1073/pnas.92.3.719
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发表时间：
1995-01-31
影响因子：
11.1
通讯作者：
WILLIAMS, LD
中科院分区：
文献类型：
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作者：
LIPSCOMB, LA;PEEK, ME;WILLIAMS, LD
我们测定了一个含7，8-二氢-8-氧代鸟嘌呤（G（O））的DNA片段的X-射线结构。d（CCAG（O）CGCTGG）的双链形式的结构已被确定为1.6埃分辨率。结果表明，G（O）与相反的C形成Watson-Crick碱基对，G（O）处于反构象。由C.G（O）（反）碱基对引起的结构扰动是微妙的。该结构使我们能够识别DNA修复蛋白MutM识别其底物的可能元件。主要沟槽内的氢键供体/受体是最可能的元素。在该凹槽中，C.G（O）（反）的氢键供体/受体模式是独特的。另外的结构分析表明，G到G（O）的转化不会显著影响核苷的糖苷扭转偏好。G（O）的8位氧与磷酸脱氧核糖骨架没有空间相互作用。
We have determined the x-ray structure of a DNA fragment containing 7,8-dihydro-8-oxoguanine (G(O)). The structure of the duplex form of d(CCAG(O)CGCTGG) has been determined to 1.6-Angstrom resolution. The results demonstrate that G(O) forms Watson-Crick base pairs with the opposite C and that G(O) is in the anti conformation. Structural perturbations induced by C.G(O)(anti) base pairs are subtle. The structure allows us to identify probable elements by which the DNA repair protein MutM recognizes its substrates. Hydrogen bond donors/acceptors within the major groove are the most likely element. In that groove, the pattern of hydrogen-bond donors/acceptors of C.G(O)(anti) is unique. Additional Structural analysis indicates that conversion of G to G(O) would not significantly influence the glycosidic torsion preference of the nucleoside. There is no steric interaction of the 8-oxygen of G(O) with the phospho-deoxyribose backbone.