DNA MICROHETEROGENEITY & BENDING

我们之前已经提出了一个B-DNA的结构模型 相当大的构象微观异质性，其中某些 片断采用“黄油苍蝇”或“菱形”图案。确认我们的 提案，我们正在确定三个齐聚物的结构 溶液的核磁共振波谱分析。对于第一种低聚物，我们有 记录并分析了以下光谱：3‘P-’H异质谱， HomoTOCSY、ECOSY、PECOSY、`P已分离，H2/H2‘’抑制J缩放 DQF，‘H-“P COSY，’H_31 P GHSQC，‘H-”水和D20中的C HSQC和NOESY 在几个混合时间。我们已经能够把所有的‘H’ 共鸣。此外，20个磷原子是由一个 走遍杂音‘H_3’P TOCSY。我们还分配了所有 13C HSQC中的糖和主干碳原子。因此，我们有一个 完整的22个糖磷酸主链的描述 AAA双链的单个残基。

We have previously proposed a structural model for B-DNA with considerable conformational microheterogeniety in which certain segments adopt "butter fly" or "rhombic" motifs. To confirm our proposal, we are determining the structure of three oligomers in solution by NMR spectroscopy. For the first oligomer, we have recorded and analyzed the following spectra: 3 'P-'H heteroTOCSY, homoTOCSY, ECOSY, PECOSY, `P decoupled, H2/H2'' suppressed J scaled DQF, 'H-"P COSY, 'H_31 P GHSQC, 'H-"C HSQC and NOESY in water and D20 at several mixing times. We have been able to assign all the 'H resonances. In addition the 20 phosphorus atoms were assigned by a walk through the hetero 'H_3 'P TOCSY. We have also assigned all the sugar and backbone carbon atoms in the 13 C HSQC. Thus, we have a complete description of the sugar phosphate backbone of the 22 individual residues of the AAA duplex.