(II) 替代增强了新设计的 (II) 碳酸无水酶的雌激酶活性
Valentina Borghesani1,2, Melissa L Zastrow1,3, Audrey E Tolbert1
1Department of Chemistry and Biophysics, University of Michigan, Ann Arbor, MI-48109-1055, United States.
Chemistry (Weinheim an der Bergstrasse, Germany)
|February 20, 2024
概括
这项研究提出了一种替代的碳酸无水酶模仿剂,在更高的pH水平下表现出增强的催化效率. 模仿的人模仿.
科学领域:
- 生物化学 生物化学
- 生物有机化学 生物有机化学
- 蛋白质设计 蛋白质设计
背景情况:
- 碳酸无水酶 (CA) 是具有简单活性位点的关键酶,这使得它们成为新型蛋白质设计的有吸引力的标.
- 早期的CA模仿利用了Zn(II),密切地复制了原生酶的活性位点协调球.
- Co(II) 提供了d7电子配置,使其能够进行详细的解决方案表征和CA模拟器的机制研究.
研究的目的:
- 为了合成和表征一种新型的 (II) 替代碳酸无水酶模仿物,[Co (II) (H2O/OH-) ]N (TRIL2WL23H) 3 n+.
- 为了研究模仿的pH依赖的催化活性和物种化.
- 为了比较模仿与其模拟物和本地人类CA的性能.
主要方法:
- 合成和表征Co (II) 替代的复合物.
- 在不同pH值下对p-nitrophenylacetate (pNPA) 的水解进行测试.
- 射线吸收光谱 (XAS) 用于确定金属协调几何.
- 紫外线光谱检测以监测pH依赖的转变,并确定pKa.
- 动力分析 (kcat,Km) 用于评估催化效率.
主要成果:
- Co(II) 模仿物表现出pH依赖的催化活性,在pH10以上变得显著活跃.
- 在高pH值下,模仿的催化效率超过了Zn (II) 模拟的催化效率.
- 在pH 11附近,XAS揭示了从八面体转变为五坐标体的物种,这种转变得到了UV视光谱学 (pKa = 10.3) 的证实.
- 动力数据与光谱变化相关,表明形成一个5坐标的Co (II) (Nimd) (OH) (H2O) 物种对于催化非常重要.
结论:
- 替代Co (II) 的碳酸无水酶模仿体表现出显著的pH依赖活性和增强的催化效率.
- 在较高的pH值下观察到的过渡到5坐标物种是直接与决定速率的水解步骤相关的.
- 这项研究提供了对碳酸无水酶模仿机制的见解,并为未来的蛋白质设计策略提供了信息.
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