Conformational dynamics of phototropin 2 LOV2 domain with the linker upon photoexcitation
Conformational dynamics of phototropin 2 LOV2 domain with the linker upon photoexcitation
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DOI：
10.1021/ja052523i
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发表时间：
2005-09-28
影响因子：
15
通讯作者：
Terazima, M
中科院分区：
文献类型：
--
作者：
Eitoku, T;Nakasone, Y;Terazima, M
利用脉冲激光诱导的瞬态光栅（TG）技术研究了植物蓝光感受器光致生长素（phototropin）LOV2结构域的构象动力学。不具有激酶结构域的接头部分的LOV2的TG信号表现出热光栅信号，这是由于从激发态释放的热和通过加合物形成的弱群体光栅。发现发色团和Cys残基之间形成化学键后的加合物产物的扩散系数略小于反应物的扩散系数，这意味着在加合物形成时核稍微收缩。在该变化之后，未观察到显著的构象变化。另一方面，具有激酶结构域的接头部分的LOV2的信号清楚地显示了原始物质和加合物物质之间非常不同的扩散系数。大的差异表明加合物形成后蛋白质部分的显著全局构象变化。更有趣的是，扩散系数被发现是时间依赖于观察时间范围内。代表全局构象变化的动力学是激发三重态和信号产物之间的光谱沉默中间体的明确指示。根据信号的时间分布分析，确定构象变化的速率为2ms。
Conformational dynamics of LOV2 domain of phototropin, a plant blue light photoreceptor, is studied by the pulsed laser induced transient grating (TG) technique. The TG signal of LOV2 without the linker part to the kinase domain exhibits the thermal grating signal due to the heat releasing from the excited state and a weak population grating by the adduct formation. The diffusion coefficients of the adduct product after forming the chemical bond between the chromophore and Cys residue are found to be slightly smaller than that of the reactant, which implies that the core shrinks slightly on the adduct formation. After that change, no significant conformational change was observed. On the other hand, the signal of LOV2 with the linker part to the kinase domain clearly shows very different diffusion coefficients between the original and the adduct species. The large difference indicates significant global conformational change of the protein moiety upon the adduct formation. More interestingly, the diffusion coefficient is found to be time-dependent in the observation time range. The dynamics representing the global conformational change is a clear indication of a spectral silent intermediate between the excited triplet state and the signaling product. From the temporal profile analysis of the signal, the rate of the conformational change is determined to be 2 ms.