Integrated analysis of cyanobacteriochromes in diversity and molecular regulation of cyanobacterial photoresponses

我们发现蓝藻具有不同的光感受器，而蓝藻对各种光色的感知是独一无二的。为了在分子水平上整合光信号系统，我们对蓝藻的生化、结构和生理方面进行了重点研究。我们测定了两个蓝藻碘变色的晶体结构，揭示了颜色调节和分子内信号传递的原子基础。我们确定了对蓝藻碘变色酶产生或降解第二信使分子--环二鸟酸的酶调节，该分子诱导嗜热蓝细菌产生纤维素和细胞聚集。我们还通过组合诱变研究阐明了蓝藻显色酶对细胞聚集的分子贡献。因此，一组蓝藻碘铬通过直接调节环二鸟酸，将各种光信号整合到纤维素的生产和细胞聚集中。

We found that cyanobacteria possess diverse photoreceptors and cyanobacteriochromes are unique in perception of wide range of light color. We focused on biochemical, structural and physiological aspects of cyanobacteriochromes in order to integrate the light signaling system at molecular level. We determined the crystal structures of two cyanobacteriochromes and revealed the atomic basis for the color tuning and intramolecular signaling. We determined enzymatic regulation of the cyanobacteriochromes to produce or degrade a second messenger molecule, cyclic diguanylic acid, which induces cellulose production and cellular aggregation in thermophilic cyanobacteria. We also elucidated the molecular contribution of the cyanobacteriochromes to the cellular aggregation by combinatorial mutagenesis studies. Thus, a set of cyanobacteriochromes integrates various light signals into the cellulose production and cellular aggregation by direct regulation of cyclic diguanylic acid.