Chandrasekaran R, Radha A, Park H S, Arnott S
Whistler Center, Purdue University West Lafayette, Indiana 47907.
J Biomol Struct Dyn. 1989 Jun;6(6):1203-15. doi: 10.1080/07391102.1989.10506545.
The crystalline beta-form of the sodium salt of poly d(A).poly d(U) trapped in oriented fibers forms a Watson-Crick base-paired, 10(1) double-helix of pitch 3.2 nm. Two molecules are present in a monoclinic unit cell apparently isomorphous with beta-poly d(A).poly d(T). The two chains in each molecule both carry C2'-endo puckered furanose rings but are conformationally not identical. The orientations of the A:U base-pairs relative to the helix-axis are distinctly different from those in classical B-DNA and the overall morphology of the duplex in which they reside resembles that of the alpha-forms of poly (purine).poly (pyrimidine) DNA duplexes previously reported.
被困在定向纤维中的聚d(A)·聚d(U)钠盐的晶体β-形式形成了一种沃森-克里克碱基配对的10(1)双螺旋，螺距为3.2纳米。在一个单斜晶胞中有两个分子，显然与β-聚d(A)·聚d(T)同晶型。每个分子中的两条链都带有C2'-内型褶皱呋喃糖环，但构象并不相同。A:U碱基对相对于螺旋轴的取向与经典B-DNA中的明显不同，并且它们所在的双链体的整体形态类似于先前报道的聚（嘌呤）·聚（嘧啶）DNA双链体的α-形式。
