结构适应性 促进细胞染色体P450中的基因结合
John A McIntosh1, Thomas Heel1, Andrew R Buller1
1Division of Chemistry and Chemical Engineering 210-41, California Institute of Technology , 1200 East California Boulevard, Pasadena, California 91125, United States.
Journal of the American Chemical Society
|August 25, 2015
概括
研究人员通过将一个关键的氨酸残留物转化为氨酸来探索P450 (CYP) 酶的活性部位. 这种结构变化为未来的研究揭示了新的催化作用和酶特性.
科学领域:
- 生物化学
- 结构生物学
- 酵素学
背景情况:
- 细胞P450 (CYP) 酶对于新陈代谢至关重要,通常利用保存的囊残留物来结合血红铁.
- 这种半氨酸的突变可以消除自然单氧基酶的活性,但可能使新的碳和转移反应成为可能.
- 了解CYP活性部位的结构是设计新催化功能的关键.
研究的目的:
- 确定与胺结合的P450酶的晶体结构.
- 调查CYP119中轴性氨酸突变的结构和功能后果.
- 探索工程化CYP活性位点的非自然催化潜力.
主要方法:
- 来自Sulfolobus acidocaldarius的热稳定性CYP119酶的位点定向突变发生.
- 进行X射线晶体学,以获得T213A/C317H变体的高分辨率结构.
- 对各种轴性半氨酸突变物的光谱分析.
主要成果:
- 确定了与胺结合的P450 (CYP119 T213A/ C317H) 的第一个晶体结构,显示了胺对血红铁的协调.
- 转变为胺导致整体蛋白质结构发生显著变化.
- 发现轴性半氨酸可以被其他氨基酸替代,而不会影响蛋白质折叠或血结合,从而产生独特的光谱特性.
结论:
- 与胺结合的P450活性位点在结构上是不同的,并保持血红蛋白协调.
- 具有多种氨基酸替代的工程化CYP活性位点是稳定的,并具有独特的特性.
- 这些发现为探索新的P450介导催化和反应机制提供了基础.
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