构建了丝氨酸蛋白酶Matriptase的催化结构域无活性突变体质粒S195A，并在酵母中表达，通过阴离子柱粗捕获及分子筛和离子交换柱纯化得到高纯度重组蛋白，通过气相扩散法得到无活性突变体的晶体. 结果表明，与野生型相比，单点突变极大程度提高了Matriptase的表达，Matriptase无活性突变体不具有水解底物活性，但仍可与抑制蛋白HAI-1结合. 晶体分辨率为1.48 ?，195A突变没有影响Matriptase的构象.

An inactivated mutant of matriptase serine protease domain (S195A) was constructed, and the recombinant protein in Pichia pastoris was expressed. After captured by anion exchange chromatography, the recombinant protein was further purified by gel-filtration chromatogram column and resource Q anion exchange column with high purity. High quality crystals of this inactivated protein were obtained by sitting-drop vapor diffusion. The results showed that the single point mutant increased the level of matriptase compared with the wild type. This inactivated mutant forms stable complex with its inhibitor HAI-1, although it does not possess catalytic activity. Crystals of this inactivated protein were diffracted to 1.48 ?. The mutant has the same conformation as the wild type.