Lin Fang, Zhou Aiwu, Wei Zhenquan
Hongqiao International Institute of Medicine, Shanghai Tongren Hospital and Faculty of Basic Medicine, and Department of Pathophysiology, Shanghai Jiaotong University School of Medicine, (Room 1006, Building 2, No 280, South Chongqing Road), Shanghai 200025, People's Republic of China.
Acta Crystallogr F Struct Biol Commun. 2015 Sep;71(Pt 9):1135-8. doi: 10.1107/S2053230X15012893. Epub 2015 Aug 25.
Kallistatin is a serine protease inhibitor (serpin) which specifically inhibits human tissue kallikrein; however, its inhibitory activity is inhibited by heparin. In order to elucidate the underlying mechanism, recombinant human kallistatin was prepared in Escherichia coli and the protein was crystallized by the sitting-drop vapour-diffusion method. X-ray diffraction data were collected to 1.9 Å resolution. The crystals were found to belong to space group P61, with unit-cell parameters a = 113.51, b = 113.51, c = 76.17 Å. Initial analysis indicated that the crystallized kallistatin was in a relaxed conformation, with its reactive-centre loop inserted in the central β-sheet.
激肽抑制蛋白是一种丝氨酸蛋白酶抑制剂（丝氨酸蛋白酶抑制剂家族），它能特异性抑制人组织激肽释放酶；然而，其抑制活性会被肝素抑制。为了阐明潜在机制，在大肠杆菌中制备了重组人激肽抑制蛋白，并通过坐滴气相扩散法使该蛋白结晶。收集了分辨率为1.9 Å的X射线衍射数据。发现晶体属于空间群P61，晶胞参数为a = 113.51、b = 113.51、c = 76.17 Å。初步分析表明，结晶的激肽抑制蛋白处于松弛构象，其反应中心环插入中央β折叠中。
