水溶液中稀土离子与甘氨酰丙氨酸作用的NMR研究

利用¹H和¹³C NMR技术研究了水溶液中稀土离子与二肽甘氨酰丙氨酸(以下简称甘-丙二肽,记为GA)的配位作用。由稀土诱导位移的浓度依赖关系计算了Yb与甘-丙二肽配合物的稳定常数。测定了重稀土离子Dy³⁺、Ho³⁺、Er³⁺、Tr³⁺和Yb³⁺作用下GA的¹³C诱导位移,并根据Reuben方法对稀土诱导位移进行了线性相关分析。对配合物中配体骨架构象的模拟分析指出,Cl-C₂-N-C₃为旁式,C₂-N-C₃-C₄和C₅-C₂-N-C₃为反交叉式。系统比较了4种含甘氨酰二肽的侧基大小对配合物稳定常数、配体构象和配合物溶液结构的影响。

NMR STUDY OF INTERACTION BETWEEN DIPEPTIDE GLY-ALA AND LANTHANIDE IONS IN AQUEOUS SOLUTION

~1H and ~(13)C NMR techniques were used to study complexation of lanthanide ions with Gly-Ala in aqueous solution. For Yb complex with Gly-Ala the stability constant was calculated from the concentration dependence of lanthanide-induced shifts. ~(13)C shifts induced by heavy lanthanide ions Dy~(3+), Ho~(3+), Er~(3+), Tm~(3+) and Yb~(3+) were analyzed by Reuben's method. The simulation for ligand conformation of lanthanide complex with Gly-Ala shows that the ligand segment C1-C2-N-C3 is in gauche form,while the segments C2-N-C3-C4 and C5-C2-N-C3 in trans form. The effects of side-group size of several glyeine-eontaining dipeptides on complex stability constants, ligand conformations and structure of complexes in solution were discussed.