Hillen W, Gassen G
Biochim Biophys Acta. 1978 Mar 29;518(1):7-16. doi: 10.1016/0005-2787(78)90111-9.
The ApU analogues ApT, Apcl5U, Apbr5U, Apa5U and Apno5(2)U were synthesized with the aid of ribonuclease U2 starting from 2',3'-cyclic Ap and the respective uridine derivatives. For these compounds the ultraviolet data, the difference spectra, the hypochromism and the temperature dependence of the CD spectra are reported. The dimerisation shifts of the pyrimidine protons which were obtained from the 100 MHz PMR spectra confirm the optical results. The influence of the substituents in the 5 position of the uracil ring on base-base interaction and the conformation of the dinucleoside phosphates is discussed with respect to the van der Waals radii and the electronic effects of these groups. As calculated from the hypochromism the dinucleoside phosphates can be arranged according to decreasing base-base interaction: Apno5(2)U greater than Apbr5U approximately ApT greater than Apcl5U greater than ApU greater than Apa5U.
借助核糖核酸酶U2，以2',3'-环腺苷酸和相应的尿苷衍生物为原料合成了ApU类似物ApT、Apcl5U、Apbr5U、Apa5U和Apno5(2)U。报道了这些化合物的紫外数据、差示光谱、减色效应以及圆二色光谱的温度依赖性。从100兆赫的核磁共振谱获得的嘧啶质子的二聚化位移证实了光学结果。结合这些基团的范德华半径和电子效应，讨论了尿嘧啶环5位取代基对碱基-碱基相互作用和二核苷磷酸酯构象的影响。根据减色效应计算，二核苷磷酸酯可按碱基-碱基相互作用减弱的顺序排列：Apno5(2)U＞Apbr5U≈ApT＞Apcl5U＞ApU＞Apa5U。
