酵母蛋白二硫化异构酶的基本功能不在于其异构酶活性
1Department of Biochemistry and Cell Biology, State University of New York at Stony Brook 11794-5215.
Cell
|September 10, 1993
概括
蛋白二硫化异构酶 (PDI) 通过催化二硫化键的形成来促进蛋白质折叠. 虽然对于酵母活力至关重要,但PDI的催化活性并不严格要求,这表明蛋白质折叠的替代途径.
科学领域:
- 生物化学 生物化学
- 分子生物学分子生物学
- 酵母遗传学 酵母遗传学
背景情况:
- 蛋白二硫化异构酶 (PDI) 对于催化二硫化键异构化至关重要,在体内有助于蛋白质折叠.
- PDI是由Saccharomyces cerevisiae的一个基本基因编码的,这突出了它在细胞过程中的重要性.
研究的目的:
- 研究PDI的体内功能,特别是其活性位点在催化和细胞活性的作用.
- 为了确定PDI的催化活性是否对酵母细胞的生存至关重要.
主要方法:
- 在S. cerevisiae中对PDI进行基因操纵,包括C-终端缺失和活性部位基因 (CGHC) 的破坏.
- 在体外酶测试以评估PDI的催化活性.
- 在改造的酵母菌株中分析细胞局部化,细胞活力和蛋白质运输 (碳氧酶Y).
主要成果:
- 删除PDI的C端残留物改变了局部化,但不能改变生命力;进一步的删除是致命的,尽管保持了体外活性.
- 两个CGHC活性位点的干扰使得PDI在体外具有催化不活性,但不会导致致死性.
- 具有催化不活的PDI的酵母细胞表现出延迟的二硫化键形成和氧酶Y运输.
结论:
- PDI在体外和体内都能催化二硫化键的形成,需要完整的活性位点进行催化.
- PDI的催化活性对酵母活力并不重要,这表明蛋白质折叠的潜在补偿机制.
相关概念视频
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