阴离子鲑鱼胰蛋白酶与牛胰蛋白酶抑制剂复合物的晶体结构。

The crystal structure of anionic salmon trypsin in complex with bovine pancreatic trypsin inhibitor.

作者信息

Helland R, Leiros I, Berglund G I, Willassen N P, Smalås A O

机构信息

Department of Chemistry, University of Tromsø, Norway.

出版信息

Eur J Biochem. 1998 Sep 1;256(2):317-24. doi: 10.1046/j.1432-1327.1998.2560317.x.

DOI:10.1046/j.1432-1327.1998.2560317.x

PMID:9760170

Abstract

The complex formed between anionic salmon trypsin (ST) and bovine pancreatic trypsin inhibitor (BPTI) has been crystallised, and the X-ray structure has been solved using the molecular replacement method. The crystals are hexagonal and belong to space group P6(1)22 with lattice parameters of a = b = 83.12 A and c = 222.15 A. Data have been collected to 2.1 A and the structure has been refined to a crystallographic R-factor of 20.6%. Catalysis by salmon trypsin is distinguished by a Km value 20-fold lower than that for mammalian trypsins, and a k(cat) twice as high. The present ST-BPTI complex serves as a model for the Michaelis-Menten complex, and has been compared with corresponding bovine and rat trypsin (RT) complexes. The binding of BPTI to salmon trypsin is characterised by stronger primary interactions in the active site, and a somewhat looser secondary binding.

摘要

阴离子鲑鱼胰蛋白酶（ST）与牛胰蛋白酶抑制剂（BPTI）形成的复合物已被结晶，并使用分子置换法解析了其X射线结构。晶体为六方晶系，属于空间群P6(1)22，晶格参数为a = b = 83.12 Å，c = 222.15 Å。已收集到2.1 Å的数据，结构已精修至晶体学R因子为20.6%。鲑鱼胰蛋白酶的催化作用特点是Km值比哺乳动物胰蛋白酶低20倍，k(cat)高两倍。目前的ST-BPTI复合物作为米氏复合物的模型，并已与相应的牛和大鼠胰蛋白酶（RT）复合物进行了比较。BPTI与鲑鱼胰蛋白酶的结合特点是活性位点的主要相互作用更强，二级结合略显松散。