蛋白质工程是一个基于在自然类的核糖核酸还原酶之间统一的进化装置的PhotoRNR幻象
David Y Song1, JoAnne Stubbe1, Daniel G Nocera1
1Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138.
概括
研究人员通过结合不同RNR类的特征来设计了一种新型光激活核酸减少酶 (RNR) 酶. 这种光化学酶模仿了II类RNR活性,在没有必要的辅因子的情况下产生脱氧核酸.
科学领域:
- 生物化学 生物化学
- 酶学 是一种酶学.
- 蛋白质工程是指蛋白质的工程.
背景情况:
- рибо核酸减少酶 (RNR) 是DNA合成的关键酶,它们将核二三酸盐转化为脱氧核酸盐.
- 现有的RNR表现出功能多样性和低序列保存,使统一机制的研究变得复杂.
- 一类RNR在某些变体 (光RNR) 中使用由光启动的基化学反应,而二类RNR则采用更简单的辅因子系统.
研究的目的:
- 通过结合II类和光RNR的特征来设计一个统一的RNR装置.
- 创建一个模拟II类酶功能的仿真化学RNR,使用光启动的激素化学.
- 调查RNR活性部位组件对于脱氧核酸合成的适应性.
主要方法:
- 通过将α子单元的截断活性位点与β子单元的C端尾部合并而设计了一个模拟RNR.
- 在激素运输通路中,在关键的氨酸残留物 (Y356) 附近加入了 ([Re]) 光氧化剂,以冷-EM结构为灵感.
- 使用细胞二酸 (CDP),腺三酸 (ATP) 和光线测试了光合物的活性.
主要成果:
- 在RNR光化学仪成功地在照明时产生了Y356•基.
- 生产了脱氧基二酸盐 (dCDP) 和细胞因子,表明活性脱氧核酸形成.
- 该酶在不需要β金属因子的情况下表现出活性,证明了10链αβ桶指环的适应性.
结论:
- 设计的RNR光化学仪通过光启动的激素化学成功模拟了II类RNR活动.
- 这种设计突出了创建具有可适应活跃站点功能的新型RNR的潜力.
- 该研究提供了对RNR机制的洞察,以及为脱氧核酸合成工程酶的设计.
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