Dynamics of protein and chromophore structural changes in the photocycle of photoactive yellow protein monitored by time-resolved optical rotatory dispersion
Dynamics of protein and chromophore structural changes in the photocycle of photoactive yellow protein monitored by time-resolved optical rotatory dispersion
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DOI：
10.1021/bi020577o
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发表时间：
2003-02-25
期刊：
影响因子：
2.9
通讯作者：
Kliger, DS
中科院分区：
文献类型：
--
作者：
Chen, EF;Gensch, T;Kliger, DS
PYP光循环的动力学已经研究了使用时间分辨旋光色散（TRORD）光谱在可见光和远紫外光谱区探测的发色团的配置和蛋白质二级结构的变化，分别。PYP中的二级结构的变化时，光异构化的发色团可以描述为两个指数寿命2 +/- 0.8和650 +/- 100毫秒，分别对应于去折叠和重折叠过程。跟踪发色团动力学的TRORD实验报告了三个指数分量，寿命为10 +/- 3 μ s，1.5 +/- 0.5 ms，和515 +/- 110 ms。发色团和蛋白质动力学行为的比较表明，在pR（465）衰减期间，在pB（355）中发现的发色团和蛋白质结构形成之前，位于发色团疏水口袋的初始松弛。相反，蛋白质和发色团的过程中发生类似的时间常数在失活的信号状态。
The dynamics of the PYP photocycle have been studied using time-resolved optical rotatory dispersion (TRORD) spectroscopy in the visible and far-UV spectral regions to probe the changes in the chromophore configuration and the protein secondary structure, respectively. The changes in the secondary structure in PYP upon photoisomerization of the chromophore can be described by two exponential lifetimes of 2 +/- 0.8 and 650 +/- 100 ms that correspond to unfolding and refolding processes, respectively. The TRORD experiments that follow the dynamics of the chromophore report three exponential components, with lifetimes of 10 +/- 3,us, 1.5 +/- 0.5 ms, and 515 +/- 110 ms. A comparison of the kinetic behaviors of the chromophore and protein shows that during the decay of pR(465) an initial relaxation that is localized to the chromophore hydrophobic pocket precedes the formation of the chromophore and protein structures found in pB(355). In contrast, the protein and chromophore processes occur with similar time constants during inactivation of the signaling state.