Anticipatory active-site motions and chromophore distortion prime photoreceptor PYP for light activation
Anticipatory active-site motions and chromophore distortion prime photoreceptor PYP for light activation
复制标题
DOI：
10.1038/nsb958
复制
发表时间：
2003-08-01
期刊：
影响因子：
--
通讯作者：
Genick, UK
中科院分区：
文献类型：
--
作者：
Getzoff, ED;Gutwin, KN;Genick, UK
蛋白质光感受器使用称为发色团的小分子辅因子来检测光。只有在受体活性位点的影响下，这些发色团才具有适合受体功能要求的光谱和光化学性质。这种蛋白质诱导的发色团性质的变化被称为光化学调谐，是一般但知之甚少的化学调谐过程的一个主要例子，蛋白质通过该过程塑造其活性位点基团的反应性。在这里，我们报告了细菌光受体光敏黄蛋白（PYP）的0.82埃分辨率X射线结构。异常精确的结构揭示了偏离预期的分子几何形状和各向异性原子位移的PYP活性位点。我们对这些偏差的分析直接指向分子内力和活性位点动力学，这些动力学调节PYP的发色团的性质以吸收蓝光，抑制荧光，并有利于所需的光驱动双键异构化。
Protein photoreceptors use small-molecule cofactors called chromophores to detect light. Only under the influence of the receptors active sites do these chromophores adopt spectral and photochemical properties that suit the receptors functional requirements. This protein-induced change in chromophore properties is called photochemical tuning and is a prime example for the general but poorly understood process of chemical tuning through which proteins shape the reactivity of their active-site groups. Here we report the 0.82-Angstrom resolution X-ray structure of the bacterial light receptor photoactive yellow protein (PYP). The unusually precise structure reveals deviations from expected molecular geometries and anisotropic atomic displacements in the PYP active site. Our analysis of these deviations points directly to the intramolecular forces and active-site dynamics that tune the properties of PYP's chromophore to absorb blue light, suppress fluorescence, and favor the required light-driven double-bond isomerization.