DNA double helical fragment at atomic resolution
DNA double helical fragment at atomic resolution
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原子分辨率的 DNA 双螺旋片段
作者：
M. Viswamitra;T. P. Singh;P. Jones;G. Sheldrick;S. A. Salisbury;L. Falvello;Z. Shakked
最近，由互补碱基组成的二核苷酸的单晶X射线衍射研究已经提供了原子分辨率下双螺旋核糖核酸的分子结构的细节。对于脱氧核苷酸还没有发表类似的研究。我们报道了脱氧四核苷酸d-pApTpApT(5′-P-adenylyl-(3′-5′)-thymidylyl-(3′-5′)-adenylyl-(3′-5′)-thymidine)(I)的结构，分辨率为1.0Å。这是第一个通过X射线衍射法确定其结构的四核苷酸。这项工作是利用小模型化合物的单晶研究来研究蛋白质-核酸相互作用的一部分。D-pApTpApT被选为第一批被研究的化合物之一，因为有证据表明聚(da-DT)具有不寻常的结合性质，并且某些DNA中的A.T富集区具有特定的生物学作用4-7。我们希望这些研究将提供关于特定碱基对和序列对DNA结构细节的影响的信息，从而有助于理解蛋白质对DNA双螺旋核苷酸序列的选择性识别。
DETAILS of the molecular architecture of double helical ribonucleic acids at atomic resolution have recently become available from single crystal X-ray diffraction studies of dinucleotides composed of complementary bases1–3. No similar studies have been published for deoxynucleotides. We report here the structure of the deoxytetranucleotide d-pApTpApT (5′-P-adenylyl-(3′-5′)-thymidylyl-(3′-5′)-adenylyl-(3′-5′)-thymidine) (I) at a resolution of 1.0 Å. This is the first tetranucleotide whose structure has been elucidated by X-ray diffraction. The work is part of an investigation of protein–nucleic acid interactions using single-crystal studies of small model compounds. d-pApTpApT was chosen as one of the first compounds to be examined because there is evidence that poly(dA–dT) has unusual binding properties and that A.T-rich regions in certain DNAs have specific biological roles4–7. We hope that these investigations will provide information about the influence of specific base pairs and sequences on the fine details of the DNA structures, and thus aid the understanding of the selective recognition of nucleotide sequences of the DNA double helix by proteins.