t-PA K1区的同源模建及Kringle区与赖氨酸相互作用的研究

利用同源模建方法预测了t-PAK1区的三维结构。通过结构叠合确定了t-PAK1、K2区,纤溶酶原K1、K4区及UKK区的赖氨酸结合口袋。静电势计算及疏水性分析表明,在t-PAK2区以及纤溶酶原K1、K4区与纤维蛋白裸露的赖氨酸之间存在明显的静电势互补和疏水面契合。确定了影响Kringle区结合口袋与赖氨酸亲和的重要氨基酸,分析了t-PAK1区、UKK区不能结合赖氨酸的原因,由此设计了具有赖氨酸亲和力的新型t-PAK1区及UKK区突变体。利用模拟残基突变技术预测了突变体的结构变化,分析了突变后t-PAK1区及UKK区与赖氨酸亲和力的变化,初步在理论上肯定了设计方案的合理性。

The Homology Modelling of t-PA K1 Domain and Computer Simulation on the Interaction Between Kringles and Lysine

Homology modelling had been used to predict the 3-D structure of t-PA K1 domain. With the structure alignment, the lysine-binding pocket of t-PA K1, K2 domain, PLG K1, K4 domain and UK K domain had been determined. Electrostatic potential calculation and hydrophobir analysis show that the pockets and lysine were in good complement for electrostatic potential or hydrophobic property. Some key residues which would influence the interaction between lysine-binding pocket of kringles and lysine were identified, and the reason that why t-PA Kl and UK K can't bind lysine as well was analyzed. New mutants of t-PA Kl and UK K were designed based on the former analysis, and the mutant structure were also predicted by simulating residues replacement. The affinity to lysine of the designed mutants were analyzed, the results indicated that an obviously improvement had obtained.