Controlling Radical Formation in the Photoactive Yellow Protein Chromophore
Controlling Radical Formation in the Photoactive Yellow Protein Chromophore
复制标题
控制光活性黄色蛋白发色团中自由基的形成
DOI：
10.1002/ange.201500549
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发表时间：
2015
影响因子：
--
通讯作者：
Mooney C
中科院分区：
文献类型：
--
作者：
Mooney C
为了了解光活性蛋白是如何起作用的，有必要了解发色团的光响应。光活性黄蛋白（PYP）是一种典型的信号蛋白。蓝光触发PYP内共价结合的发色团的反式异构化，这是光循环的第一步，导致宿主细菌远离潜在的有害光。在高能量下，光吸收有可能产生自由基和自由电子；然而，这一过程在很大程度上尚未被探索。在这里，我们使用光电子能谱和量子化学计算表明，分离的PYP发色团的分子结构和构象可以用来控制反式顺式异构化和自由基形成之间的竞争。我们还发现证据表明，该蛋白的作用之一是通过阻止发色团电子基态的扭转运动来阻止PYP中自由基的形成。
To understand how photoactive proteins function, it is necessary to understand the photoresponse of the chromophore. Photoactive yellow protein (PYP) is a prototypical signaling protein. Blue light triggers trans–cis isomerization of the chromophore covalently bound within PYP as the first step in a photocycle that results in the host bacterium moving away from potentially harmful light. At higher energies, photoabsorption has the potential to create radicals and free electrons; however, this process is largely unexplored. Here, we use photoelectron spectroscopy and quantum chemistry calculations to show that the molecular structure and conformation of the isolated PYP chromophore can be exploited to control the competition between trans–cis isomerization and radical formation. We also find evidence to suggest that one of the roles of the protein is to impede radical formation in PYP by preventing torsional motion in the electronic ground state of the chromophore.