Studies on the structures and mechanisms of algal photoreceptors

光依赖反应不仅在高等植物的形态发生中起着重要作用，而且在绿藻和红藻对细胞反应的调节中也起着重要作用。现在有几种隐色素被证明可以在绿藻中调节蓝光反应，在莱茵衣藻CRY的情况下，甚至可以调节红光反应。了解它们体内光生物学的一个重要前提是首先鉴定藻类隐色素中的同源天线辅助因子。其次，对它们的氧化还原状态依赖结构的分析将允许将它们的光化学和信号功能与结构变化联系起来，并描绘出与假定的下游调控因子的相互作用部位。金色蛋白是一类新的蓝光依赖转录因子，仅在几种藻类中发现，与其他LOV调节的信号蛋白不同的是它们的倒置结构域组织。我们将用X射线结晶学分析它们与同源DNA络合时的亮态结构，并与它们的暗态结构进行比较。在这里，最终的目标是获得分子内信号传递和金色蛋白激活转录的分子基础。

Light-dependent responses play major roles not only in the morphogenesis of higher plants, but also in the regulation of cellular responses by green and red algae. Several cryptochromes are now demonstrated to mediate blue-light and, in the case of aCRY from Chlamydomonas reinhardtii, even red-light responses in green algae. An important prerequisite for understanding their in vivo photobiology is first the identification of cognate antenna cofactors in algal cryptochromes. Secondly, analysis of their redox-state dependent structures will then allow to correlate their photochemistry and signalling function with structural alterations and delineate interaction sites with putative downstream regulators. Aureochromes are a novel class of blue-light-dependent transcription factors, which are found only in several algae and differ by their inverted domain organisation from other LOV-regulated signalling proteins. We will analyse their lit state structures by X-ray crystallography when complexed to cognate DNA and compare them with their dark state structures. Here, the final goal is to obtain the molecular basis for intra-molecular signal transfer and transcription activation by aureochromes.