Zhu Y, Huang Q, Qian M, Jia Y, Tang Y
Department of Chemistry, Peking University, Beijing, China.
J Protein Chem. 1999 Jul;18(5):505-9. doi: 10.1023/a:1020690931043.
The stoichiometric complex formed between bovine beta-trypsin and Momordica charantia, Linn. Cucurbitaceae trypsin inhibitor A (MCTI-A) was crystallized and its X-ray crystal structure was refined to a final R value of 0.179 using data of 7.0- to 1.8-A resolution. Combination with results on the complex of MCTI-A with porcine trypsin gives the sequence of MCTI-A definitely, of which 13 residues are conserved compared with other squash family trypsin inhibitors. Its spatial structure and the conformation of its primary binding segment from Cys3I (P3) to Glu7I (P3'), which contains a reactive scissile bond Arg5I C-Ile6I N, were found to be very similar to the other squash family proteinase inhibitors.
牛β-胰蛋白酶与苦瓜（葫芦科苦瓜属植物，Linn.）的葫芦科胰蛋白酶抑制剂A（MCTI-A）形成的化学计量复合物被结晶，利用7.0至1.8埃分辨率的数据将其X射线晶体结构精修至最终R值为0.179。结合MCTI-A与猪胰蛋白酶复合物的结果，明确了MCTI-A的序列，与其他南瓜家族胰蛋白酶抑制剂相比，其中有13个残基是保守的。发现其空间结构以及从Cys3I（P3）到Glu7I（P3'）的主要结合片段的构象，其中包含一个反应性可裂解键Arg5I C-Ile6I N，与其他南瓜家族蛋白酶抑制剂非常相似。
