物理化学学报 >> 1987, Vol. 3 >> Issue (06): 565-569.doi: 10.3866/PKU.WHXB19870602

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Urokinase片断的二级、三级结构预测及构效关系研究

徐筱杰; 关玥; 陈忠国; 李根培; 罗宇; 来鲁华; 唐有祺; 刘建宁; 朱德煦   

  1. 北京大学化学系 南京大学生物系
  • 收稿日期:1987-07-08 修回日期:1987-08-02 发布日期:1987-12-15

THE SECONDARY STRUCTURE AND TERTIARY STRUCTURE PREDICTION OF UROKINASE FRAGMENTS AND THEIR STRUCTURE-ACTIVITY RELATIONSHIP RESEARCH

Xu Xiaojie; Guan Yue; Chen Zhongguo; Li Genpei; Luo Yu; Lai Luhua; Tang Youqi; Liu Jianning; Zhu Dexu   

  1. Department of Chemistry; Peking University
    Department of Biology; Nanjing University
  • Received:1987-07-08 Revised:1987-08-02 Published:1987-12-15

Abstract: Similar to other serine proteinases, the pertinent active site amino acids are preserved in urokinase and the amino acids forming the specific pocket shows a considerable homology with other serine proteinases, especially with trypsin. But urokinase can not be inhibited by pancreatic trypsin inhibitor (PTI) which is the best inhibitor of trypsin. Using Chou-Fasman and ECEPP/2 programs the secondary structure and tertiary structure of urokinase fragments 177-189(UKf2)and 245-255 (UKf1) were predicted in order to investigate the reason of different activities between urokinase and trypsin.
The results showed that amino acids 246-252 in UKf1 formed a α-helix structure. The dihedral angles φ of these residues were around -57° and Ψ -47°. Amino acids 185-188 in UKf2 formd a β-sheet, 181-184 were in a β-turn structure. Comparing with the stereoscopric structure of the corresponding fragments in trypsin, it can be found that since the lack of two residues in trypsin in the fragment corresponding to UKf1, only a turn structure existed in this fragment. The existance of α-helix structure in UKf1 hindered the combining of PT1 with the active sites of UK and made urokinase not being inhibited by PTI.