通过蛋白质表面的氨基酸替代来缓解反向水效应
1Department of Biology, Massachusetts Institute of Technology, Cambridge 02139.
Nature
|March 22, 1990
概括
蛋白质表面上的氨基酸替代很少影响稳定性. 然而,LambdaCro蛋白在26位的突变显著增加了稳定性,与侧链水性降低相关.
科学领域:
- 蛋白质的生物化学 蛋白质的生物化学
- 分子生物学分子生物学
- 结构生物学是结构生物学.
背景情况:
- 蛋白质表面上的氨基酸替代通常对蛋白质稳定性的影响很小.
- 兰巴克罗蛋白是研究蛋白质稳定性的模型系统.
研究的目的:
- 为了研究氨基酸替代在LambdaCro的位置26对蛋白质稳定性的影响.
- 探索侧链疏水性和蛋白质稳定性在这种表面暴露位置之间的关系.
主要方法:
- 局部定向突变发生,在Lambda Cro.的26位引入各种氨基酸替代.
- 不同扫描热量计用于测量化温度和蛋白质稳定性的变化.
- 对Cro晶体结构的分析,以评估残留物的溶剂可访问性 26.
主要成果:
- 兰巴克罗的A Tyr 26 to Cys突变使化温度增加了11°C,稳定性增加了2.2 kcal mol-1.
- 在位置26的多种氨基酸替代增强了蛋白质的稳定性.
- 增加蛋白质稳定性与26位侧链水性降低相关.
结论:
- 表面氨基酸替代可以显著改变蛋白质的稳定性.
- 在Lambda Cro的超暴露位置26的疏水性侧链似乎被反向疏水效应破坏了稳定.
- 在特定的表面残留物中调节疏水性为蛋白质工程和稳定提供了一种策略.
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