Solution Structure of xDNA: A Paired Genetic Helix with Increased Diameter

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• 作者：Haibo Liu ; Stephen R. Lynch ; and Eric T. Kool
• 刊名：Journal of the American Chemical Society
• 出版年：2004
• 出版时间：June 9, 2004
• 年：2004
• 卷：126
• 期：22
• 页码：6900 - 6905
• 全文大小：247K
• 年卷期：v.126,no.22(June 9, 2004)
• ISSN：1520-5126

文摘

We describe the structure in aqueous solution of an extended-size DNA-like duplex with basepairs that are ~2.4 Å longer than those of DNA. Deoxy-lin-benzoadenosine (dxA) was employed as a dAanalogue to form hydrogen-bonded base pairs with dT. The 10mer self-complementary extendedoligodeoxynucleotide 5'-d(xATxAxATxATTxAT) forms a much more thermodynamically stable duplex thanthe corresponding DNA sequence, 5'-d(ATAATATTAT). NMR studies show that this extended DNA (xDNA)retains many features of natural B-form DNA, but with a few structural alterations due to its increasedhelical diameter. The results give insight into the structural plasticity of the natural DNA backbone andlend insight into the evolutionary origins of the natural base pairs. Finally, this structural study confirms thehypothesis that extended nucleobase analogues can form stable DNA-like structures, suggesting thatalternative genetic systems might be viable for storage and transfer of genetic information.