用银替代的Mo/CuCO-脱酶的CO氧化机制 - 与原生酶的相似之处和差异
Anna Rovaletti1, Giorgio Moro2, Ugo Cosentino1
1Department of Earth and Environmental Sciences, Milano-Bicocca University, Piazza della Scienza 1, Milano, 20126, Italy.
概括
在CO-脱酶 (CODH) 中的白银替代使该酶能够像原生铜形式一样氧化一氧化碳 (CO). 这项研究揭示了与银的C-O键形成较低的激活能量,影响了催化效率.
科学领域:
- 生物化学 生物化学
- 酶学 是一种酶学.
- 计算化学计算化学
背景情况:
- 土壤细菌Oligotropha carboxidovorans使用含Mo/Cu的CO-脱酶 (CODH) 来氧化一氧化碳 (CO).
- 在CODH活性部位中的铜可以实验性地用银取代,从而产生一种功能性酶.
研究的目的:
- 通过使用QM/MM计算,研究用白银替代的CODH的反应机制.
- 将白银替代酶的催化途径和能量与原生铜酶进行比较.
主要方法:
- 使用量子力学/分子力学 (QM/MM) 的计算.
- 该研究的重点是CO氧化和中间产物形成的催化循环.
主要成果:
- 替代银的酶氧化CO,并通过与原生酶相同的步骤释放CO2.
- 发现了10.4kcal/mol的计算速度限制步骤,与实验数据一致.
- 对于银的C-O键形成,观察到较低的激活能量,而二碳酸盐中间体的形成在能量上是不利的.
结论:
- 在CODH中替代银维持了CO氧化过程的整体催化机制.
- 银的替代影响过渡状态稳定和C-O键形成的能量.
- 硫碳酸盐中间体的形成对于白银替代酶的催化是不必要的.
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