活体中二硫化键形成所需的DSbA蛋白质的晶体结构
J L Martin1, J C Bardwell, J Kuriyan
1Rockefeller University, New York, New York.
Nature
|September 30, 1993
概括
细菌蛋白DsbA通过氧化氨酸残留物来加速蛋白质折叠. 它的晶体结构显示出独特的域排列,表明它在二硫化键形成之前与未折叠的蛋白质结合.
科学领域:
- 生物化学 生物化学
- 结构生物学 结构生物学
- 分子生物学分子生物学
背景情况:
- 在体外蛋白质折叠可能很慢,特别是对于具有二硫化键的蛋白质,由于限制氨酸氧化和配对的速度.
- 细菌蛋白DsbA (二硫化键A) 显著加速了大肠杆菌中二硫化键蛋白质的折叠.
- 通过DSBA提高折叠率的确切机制仍然不完全理解.
研究的目的:
- 阐明DsbA提高蛋白质折叠速度的结构基础.
- 了解DSbA在促进二硫化物键形成中的作用机制.
主要方法:
- 使用X射线晶体学来确定氧化DsbA的三维结构.
- 进行了与其他氧化还原蛋白 (如硫素) 的结构比较.
主要成果:
- 氧化DsbA的晶体结构显示出类似于氧化还原蛋白thioredoxin的折叠.
- 一个关键的结构差异是DsbA中的一个额外的域,该域封闭了类似硫素的活性部位.
- 活性位点二硫化键位于一个域接口,周围有槽和暴露的疏水性侧链.
结论:
- DsbA的结构表明,该机制涉及与部分折叠的多链结合.
- 独特的域排列促进了囊残留的氧化和二硫化键的形成.
- 这种结构洞察力为了解DSbA在蛋白质折叠加速中的作用提供了基础.
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