镧系离子核磁共振探针法在分子构象研究中的应用:三种核苷酸分子在不溶液中的构象分析

本文应用镧系离子作为核磁共振探针的方法, 研究了5'CMP,5-AMP以及5-IMP三种核苷酸在酸性水溶液中的构象分布, 将实验测得的'HNMR谱的镧系诱导假接触位移, 纵向弛豫速率增强以及邻位自旋耦合常数等数据用计算机进行分析处理, 结果表明, 核苷酸分子在水溶液中的构象以一组构象异构体平衡共存, 与晶态相比,分子中绕单键旋转的二面角以及戊糖环的折叠形式均有一定的变化但, 碱基仍以稳定的反式存在。

Application of lanthanide lons as probes of nulcear magnetic resonance to studies of molecular conformations

Lanthanide ions were used as NMR probes to study the conformation distributions of 5'-CMP, 5'-AMP, and 5'-IMP in acidic aqueous solns. The experimental data of pseudo-contact shift together with the data of spin-lattice relaxation rate as well as spin-coupling constants of 1H spectra were processed by computer. The results show that in aqueous solns. the conformations of the nucleotides exist in equilibrium as a group of conformers. In comparison with crystalline state, the dihedral angles around single bonds and the puckering forms of ribose ring have changed to some extent. However, the base groups are still in anti-forms.