Lee I-Ren, Lee Wonchul, Zewail Ahmed H
Arthur Amos Noyes Laboratory of Chemical Physics, Laboratory for Molecular Sciences, California Institute of Technology, Pasadena, CA 91125, USA.
Proc Natl Acad Sci U S A. 2006 Jan 10;103(2):258-62. doi: 10.1073/pnas.0510015103. Epub 2006 Jan 3.
The cycle of the photoactive yellow protein (PYP) has been extensively studied, but the dynamics of the isolated chromophore responsible for transduction is unknown. Here, we present real-time observation of the dynamics of the negatively charged chromophore and detection of intermediates along the path of trans-to-cis isomerization using femtosecond mass selection/electron detachment techniques. The results show that the role of the protein environment is not in the first step of double-bond twisting (barrier crossing) but in directing efficient conversion to the cis-structure and in impeding radical formation within the protein.
光活性黄色蛋白（PYP）的循环已得到广泛研究，但负责信号转导的孤立发色团的动力学尚不清楚。在此，我们利用飞秒质量选择/电子脱离技术，对带负电荷的发色团的动力学进行了实时观测，并检测了反式-顺式异构化路径上的中间体。结果表明，蛋白质环境的作用不在于双键扭曲（越过势垒）的第一步，而在于引导高效转化为顺式结构以及阻止蛋白质内自由基的形成。
