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Novel cysteine proteinase inhibitor from Bombyx mori-its function and origin-

家蚕新型半胱氨酸蛋白酶抑制剂-其功能和起源-

基本信息

批准号：
12640663
负责人：
YAMAMOTO Yoshimi
金额：
$ 0.83万
依托单位：
Yamaguchi University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12640663/
关键词：
Cysteine Proteinase Inhibitor Propeptide Silkmoth Mouse Drosophila

项目摘要

Bombyx cysteine proteinase inhibitor (BCPI) is a novel cysteine proteinase inhibitor. The protein sequence is homologous to the proregions of certain cysteine proteinases. Here we report its mechanism of inhibition of several cysteine proteinases. BCPI strongly inhibited Bombyx cysteine proteinase (BCP) activity with a Ki=5.9 pM, and human cathepsin L with a Ki=36 pM. The inhibition obeyed slow-binding kinetics. The inhibition of cathepsin H was much weaker (Ki = 82 nM), while inhibition of papain (Ki > 1mM) and cathepsin B (Ki > 4mM) was negligible. Following incubation with BCP, BCPI was first truncated at the C-terminal end, and then gradually degraded for prolonged time. The truncation occured mainly by two C-terminal amino acid residues. Recombinant BCPI lacking the two C-terminal amino acid residues still retained substantial inhibitory activity. Our results indicate that BCPI is a stable and highly selective inhibitor of cathepsin L-like cysteine proteinases. Mouse activated T-lymphocytes express cytotoxic T-lymphocyte antigen (CTLA-2), which is homologous to the proregion of mouse cathepsin L. Recombinant cytotoxic T-lymphocyte antigen (CTLA-2a) also exhibited selective inhibition of cathepsin L-like cysteine proteinases. From these results, we propose that the BCPI and CTLA-2 are a new member of cysteine proteinase inhibitors, and are highly selective inhibitors of cathepsin L-like cysteine proteinases. Genome analyses have shown the expression of similar propeptide-like proteins in Drosophila and rat, suggesting the presence of a novel class of cysteine proteinase inhibitors in a variety of organisms. Studies of the gene structures and phylogenetic analysis have shown that genes of the propeptide-like cysteine proteinase inhibitors have emerged from ancestor genes of their parental enzymes.

家蚕半胱氨酸蛋白酶抑制剂(BCPI)是一种新型的半胱氨酸蛋白酶抑制剂。该蛋白质序列与某些半胱氨酸蛋白酶的前区同源。在这里，我们报告了它对几种半胱氨酸蛋白酶的抑制机制。BCPI对家蚕半胱氨酸蛋白酶有较强的抑制作用，其Ki=5.9 pM，对人组织蛋白酶L的抑制作用较强，其Ki为36 pM。抑制作用遵循慢结合动力学。组织蛋白酶H的抑制作用较弱(Ki=82 nM)，而木瓜蛋白酶(Ki&gt；1 mM)和组织蛋白酶B(Ki&gt；4 mM)的抑制作用可忽略不计。在与BCP孵育后，BCPI首先在C末端被截断，然后逐渐降解，并持续较长时间。截短主要由两个C端氨基酸残基组成。缺少两个C端氨基酸残基的重组BCPI仍具有较强的抑制活性。我们的结果表明，BCPI是一种稳定的、高选择性的组织蛋白酶L样半胱氨酸蛋白酶的抑制剂。小鼠活化的T淋巴细胞表达与小鼠组织蛋白酶L区同源的细胞毒性T淋巴细胞抗原(CTLA-2)，重组细胞毒性T淋巴细胞抗原(CTLA-2a)对组织蛋白酶L样半胱氨酸蛋白酶也有选择性抑制作用。根据这些结果，我们认为BCPI和CTLA-2是半胱氨酸蛋白酶抑制剂的新成员，是组织蛋白酶L样半胱氨酸蛋白酶的高选择性抑制剂。基因组分析表明，在果蝇和大鼠中也表达了类似的前肽蛋白，这表明在各种生物体中存在一类新的半胱氨酸蛋白酶抑制剂。基因结构的研究和系统发育分析表明，前肽样半胱氨酸蛋白酶抑制剂的基因是从其亲本酶的祖先基因中产生的。