PINE promotes dark oligomerization of the BLUF photoreceptor PixD
PINE promotes dark oligomerization of the BLUF photoreceptor PixD
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DOI：
10.1073/pnas.0802149105
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发表时间：
2008-08-19
影响因子：
11.1
通讯作者：
Bauer, Carl E.
中科院分区：
文献类型：
--
作者：
Yuan, Hua;Bauer, Carl E.
蓝细菌感知和移动（phototax）响应蓝光。在这项研究中，我们证明了PixD蓝光传感使用FAD（BLUF）光感受器，管理这种响应经历了光照时寡聚化状态的变化。在黑暗条件下，我们观察到PixD与另一种名为PixE的蛋白质形成了一种大分子量的复合物。化学计量分析，结合沉降平衡和尺寸排阻色谱，证明PixE在黑暗条件下驱动PixD二聚体聚集成稳定的PixD（10）-PixE（5）复合物。照射PixD中的黄素发色团使PixD（10）-PixE（5）复合物不稳定为PixE的单体和PixD的二聚体。PixD的晶体结构，加上PixD相互作用面之间的吉布斯自由能计算，有助于建立一个模型，其中光诱导关键PixD界面环中的构象变化，导致PixD（10）-PixE（5）复合物的不稳定。
Cyanobacteria perceive and move (phototax) in response to blue light. In this study, we demonstrate that the PixD blue light-sensing using FAD (BLUF) photoreceptor that governs this response undergoes changes in oligomerization state upon illumination. Under dark conditions we observed that PixD forms a large molecular weight complex with another protein called PixE. Stoicheometric analyses, coupled with sedimentation equilibrium and size exclusion chromatography, demonstrates that PixE drives aggregation of PixD dimers into a stable PixD(10)-PixE(5) complex under dark conditions. Illumination of a flavin chromophore in PixD destabilizes the PixD(10)-PixE(5) complex into monomers of PixE and dimers of PixD. A crystallographic structure of PixD, coupled with Gibbs free energy calculation between interacting faces of PixD, lends to a model in which a light induces a conformational change in a critical PixD-interfacing loop that results in destabilization of the PixD(10)-PixE(5) complex.