DNA MICROHETEROGENEITY & BENDING

我们以前提出了一个B-DNA的结构模型， 相当大的构象微异质性，其中某些 片段采用“蝴蝶”或“菱形”图案。 确认我们 建议，我们正在确定三个低聚物的结构， 溶液通过NMR光谱法。 对于第一低聚物，我们有 记录并分析下列光谱：3 ′ P-H heterotocsY， homoTOCSY、ECOSY、PECOSY、“P去耦、H2/H2”抑制J缩放 DQF、'H-“P COSY、'H_31 P GHSQC、'H-“C HSQC和NOESY在水和D20中的浓度 在几个混合时间。 我们已经能够分配所有的'H 共振 此外，20个磷原子由一个 通过异性恋“H_3”P TOCSY。 我们还分配了所有 糖和13 C HSQC中的主链碳原子。 因此，我们有一个 22个糖磷酸骨架的完整描述 AAA双链体的单个残基。

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.