关于非血红素Fe (II) 酶SyrB2反应性的第一原则研究
Heather J Kulik1, Leah C Blasiak, Nicola Marzari
1Department of Materials Science & Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA. hjkulik@mit.edu
Journal of the American Chemical Society
|October 8, 2009
概括
计算研究揭示了SyrB2原酶的功能. 这项研究表明,α-甲酸脱碳化很容易,但抽取有障碍,而化没有障碍,并与抽取相结合.
科学领域:
- 生物化学和酶学 生物化学和酶学
- 计算化学是一种计算化学.
- 生物有机化学 生物有机化学
背景情况:
- SyrB2是一种依赖alpha-ketoglutarate (alphaKG) 的原酶,参与syringomycin生物合成.
- 基酶和基酶具有结构和化学相似之处,在alphaKG脱碳化后,它们的催化机制不同.
- 突变研究未能将基酶和基酶活动相互转换,这表明有不同的机制要求.
研究的目的:
- 通过计算来研究SyrB2酶活性部位的反应机制.
- 探索可能的反应途径,并使用模型复合体确定调节酶活性的关键步骤.
- 阐明单个步骤的能量贡献及其在催化循环中的合.
主要方法:
- 密度函数理论 (DFT) 计算与哈巴德U校正用于精确建模Fe (II) 化学.
- 利用了一个简化的模型复合体,包括铁中心及其直接连接体.
- 分析了反应途径,包括alphaKG脱碳化,抽取,以及激素化/化.
主要成果:
- 阿尔法-谷氨酸脱碳化是一种无障碍和外热的初始步骤.
- 提取的过程呈现出一种生物可访问的能量屏障,当与化相结合时,这种屏障会降低.
- 极端化是无障碍的和外热的,而类似的化在模型系统中具有很小的能量障碍.
结论:
- 化的能量优势及其与抽取的合解释了酶活性.
- 突变基酶可能由于基质结合不良而缺乏化,而突变基酶由于能量障碍而无法化.
- 活性部位的最小模型复合物可以有效地解释酶活性的关键方面.
相关概念视频
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