Thiyagarajan P, Ponnuswamy P K
Biophys J. 1981 Sep;35(3):753-69. doi: 10.1016/S0006-3495(81)84825-4.
Following the procedure described in the preceding article, the low energy conformations located for the four dimeric subunits of RNA, ApG, ApU, CpG, and CpU are presented. The A-RNA type and Watson-Crick type helical conformations and a number of different kinds of loop promoting ones were identified as low energy in all the units. The 3E-3E and 3E-2E pucker sequences are found to be more or less equally preferred; the 2E-2E sequence is occasionally preferred, while the 2E-3E is highly prohibited in all the units. A conformation similar to the one observed in the drug-dinucleoside monophosphate complex crystals becomes a low energy case only for the CpG unit. The low energy conformations obtained for the four model units were used to assess the stability of the conformational states of the dinucleotide segments in the four crystal models of the tRNAPhe molecule. Information on the occurrence of the less preferred sugar-pucker sequences in the various loop regions in the tRNAPhe molecule has been obtained. A detailed comparison of the conformational characteristics of DNA and RNA subunits at the dimeric level is presented on the basis of the results.
按照前文所述的步骤，展示了针对RNA的四个二聚体亚基ApG、ApU、CpG和CpU所定位的低能量构象。在所有单元中，A-RNA型和沃森-克里克型螺旋构象以及许多不同种类的促进环化的构象被确定为低能量构象。发现3E-3E和3E-2E褶皱序列或多或少同样受到青睐；2E-2E序列偶尔受到青睐，而2E-3E在所有单元中都被高度禁止。一种与在药物-二核苷单磷酸复合物晶体中观察到的构象相似的构象仅对于CpG单元成为低能量情况。从四个模型单元获得的低能量构象被用于评估苯丙氨酸tRNA分子的四个晶体模型中二核苷酸片段构象状态的稳定性。已经获得了关于苯丙氨酸tRNA分子各个环区域中较不受青睐的糖-褶皱序列出现情况的信息。基于这些结果，在二聚体水平上对DNA和RNA亚基的构象特征进行了详细比较。
