极高的室温动态同位素效应量化了屏障宽度在酶C-H激活中的关键作用
Shenshen Hu1, Sudhir C Sharma, Alexander D Scouras
1Department of Chemistry, University of California , Berkeley, California 94720, United States.
Journal of the American Chemical Society
|June 3, 2014
概括
豆氧化酶 (SLO) 呈现出显著的气道化. 突变的SLO残留物揭示了活性位点的灵活性和屏障宽度如何控制这种量子道,这对生物反应至关重要.
科学领域:
- 生物化学 生物化学
- 酶学 是一种酶学.
- 量子生物学 量子生物学
背景情况:
- 豆氧化酶 (SLO) 是研究气道反应的模型酶.
- 不寻常的动态同位素效应 (KIEs) 和它们在SLO中的温度依赖性表明了复杂的反应机制.
研究的目的:
- 调查活跃地点灵活性和捐赠者-接受器距离在SLO道道中的作用.
- 阐明生物系统中酶结构和量子力学道化之间的相互作用.
主要方法:
- 动力学研究和动力同位素效应 (KIE) 测量.
- 位点特异性突变发生以改变活性位点残留物.
- 在1.7 Å分辨率的X射线晶体学.
- 理论建模包括非adiabatic量子道理论.
主要成果:
- 在SLO中疏水性残留物的突变变异能减少了10^4倍的反应速率.
- 在突变SLO.中观察到一个前所未有的,大型室温KIE.
- X射线结构揭示了扩大的活性部位腔,没有显著的脊柱或侧链形状变化.
- 动力数据符合非adiabatic模型,表明活动现场扩张限制道.
结论:
- 酶活性部位的灵活性显著影响气道化速率.
- 室温量子道是生物系统中令人信服的特性.
- 气道对反应屏障的宽度非常敏感.
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