沙佩罗宁过度表达促进了基因变异和酶进化
Nobuhiko Tokuriki1, Dan S Tawfik
1Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel.
Nature
|June 5, 2009
概括
像大肠杆菌GroEL/GroES的缓冲突变,促进更快的进化. 这些热冲击蛋白的过度表达通过帮助不稳定的蛋白质变体的折叠加速了酶适应.
科学领域:
- 分子生物学分子生物学
- 进化生物学 进化生物学
- 生物化学 生物化学
背景情况:
- 蛋白质突变往往会降低稳定性,并且是有害的.
- 伴侣蛋白 (热冲击蛋白) 可能缓冲突变,促进适应.
- 沙佩罗宁在缓冲破坏稳定和适应性突变中的作用需要进一步研究.
研究的目的:
- 为了研究大肠杆菌GroEL/GroES chaperonins的缓冲破坏稳定性和适应性突变的能力.
- 为了确定是否Chaperonin的过度表达会影响蛋白质进化和适应的速度.
主要方法:
- 在实验室中,使用四种不同的酶进行了突变漂移实验.
- 过度表达GroEL/GroES沙佩罗宁,以评估它们对突变积累和蛋白质折叠的影响.
- 分析了蛋白质核心突变或显著破坏稳定的效应的酶变异.
主要成果:
- 过度表达GroEL/GroES使累积突变的数量增加了一倍.
- 沙佩罗宁促进了具有破坏稳定的突变的酶变体的折叠 (平均>3.5 kcal mol(-1) 与没有沙佩罗宁的~1 kcal mol(-1).
- 在GroEL/GroES过度表达下,酶特异性差异发生的速度明显更快,更多的适应变体显示出更好的活性 (>10倍).
结论:
- 蛋白质稳定性是蛋白质进化中的一个关键限制.
- 沙佩罗宁作为关键的缓冲机制,减轻稳定性约束和加速适应性进化.
- 了解伴侣功能对于理解进化过程和蛋白质工程至关重要.
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