Functional and structural characterization of bacterial blue-light sensitive photoreceptors

在许多原核生物基因组中已经发现了编码蓝光敏感光感受器的序列基序，这些基序与它们的植物对应物具有高度相似性。这种相似性也被发现为几个异源表达的基因产物，显示向光蛋白典型的光谱反应。然而，除了相似之处，光驱动动力学的显着差异被检测到。与植物的原体相比，原核生物的向光蛋白相关蛋白更易于全长表达。这允许进入光诱导的信号转导的研究，因为许多这些受体携带-除了发色团结合基序-组氨酸激酶结构域在其C-末端部分，与类似地存在的Chey样反应调节剂相互作用，使它们成为蓝光驱动的细菌双组分信号转导系统的新成员。我们已经描述了芽孢杆菌蛋白YtvA的光谱特性，然而，对于更精确的分析，包括突变体的产生和其在同源系统中的行为的研究，存在强烈的需求。通过蛋白质结晶的结构测定实验已经开始。

Sequence motifs encoding blue-light sensitive photoreceptors with high similarity to their plant counterparts have been identified in many prokaryote genomes. This resemblance was found also for several heterologously expressed gene products that show the phototropin-typical spectroscopic reactions. However, besides similarities, significant differences in the light-driven kinetics were detected. In contrast to the plant protomers, the prokaryote phototropin-related proteins are more prone to full-length expression. This allows an access to the study of the light induced signal transduction, since many of these receptors carry - besides the chromophore-binding motif - a histidine kinase domain in their C-terminal part that interacts with similarly present CheY-like response regulators, making them new members of a blue light-driven bacterial two-component signal transduction system. The spectroscopic properties of the Bacillus protein YtvA have already been described by us, however, there is strong demand for a more precise analysis, including the generation of mutants and a study of its behavior in the homologous system. Structure determination experiments by protein crystallization have been initiated.