Department of Botany, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan.
Curr Opin Plant Biol. 2010 Oct;13(5):565-70. doi: 10.1016/j.pbi.2010.07.002.
Phytochrome mediates various physiological as well as developmental responses to light stimuli in plants. Phytochrome is a soluble chromoprotein consisting of the N-terminal photosensory and C-terminal dimerization moieties. Close homologues of plant phytochromes are widely found in prokaryotes. Recently, the crystal structures of the core photosensory module of bacterial phytochromes are resolved. Intriguingly, three sub-domains (PAS, GAF and PHY) in the module are connected by unusual structures named 'light-sensing knot' and 'tongue', which are in tight contact with the chromophore. These findings enable us to review previous data on the structure-function relationships in phytochrome. Consequently, functional importance of these peculiar structures is further highlighted. Thus, the three-dimensional structure provides a framework for understanding how phytochrome processes the light signals.
光敏色素介导植物对光刺激的各种生理和发育反应。光敏色素是一种可溶性的色蛋白，由 N 端感光和 C 端二聚化结构域组成。植物光敏色素的密切同源物广泛存在于原核生物中。最近，细菌光敏色素核心感光模块的晶体结构已被解析。有趣的是，模块中的三个亚结构域（PAS、GAF 和 PHY）通过被称为“感光结”和“舌”的不寻常结构连接在一起，它们与发色团紧密接触。这些发现使我们能够回顾以前关于光敏色素结构-功能关系的数据。因此，这些特殊结构的功能重要性进一步得到强调。因此，三维结构为理解光敏色素如何处理光信号提供了一个框架。
