作者:Irena Ekiel、Edward Darżynkiewicz、David Shugar
DOI:10.1016/s0008-6215(00)85979-0
日期:——
the existence, for a broad range of analogs, of a two-state, conformational equilibrium, N⇌S (or 2 E ⇌ 3 E ). As between different analogs, there is a large variation in the relative populations of these two states that is related to the nature of the aglycon, the type of protecting groups on the sugar hydroxyl groups, and, to a much smaller extent, the solvent system. There is a striking correlation
摘要研究了溶液中许多α-d-和-1- l-阿拉伯糖基呋喃糖基核苷的糖部分的构象,主要是借助于为此目的开发的统计程序。总体结果表明,对于广泛的类似物,存在两种状态的构象平衡N⇌S(或2 E⇌3 E)。在不同的类似物之间,这两种状态的相对种群存在很大的变化,这与糖苷配基的性质,糖羟基上的保护基团的类型以及较小的溶剂体系有关。糖的构象与环外羟甲基的取向之间存在惊人的相关性。对于嘌呤和嘧啶核苷,环外基团的gauche-gauche rotamer的优势与呋喃糖环的N型状态相关,而与S型状态相比,gauche-gauche rotamer种群实际上不存在。与9-α-d-阿拉伯呋喃糖基腺嘌呤的X射线衍射数据比较表明,与其他类别的核苷一样,固态构象对应于参与溶液平衡的状态之一。