Identification of DXCF cyanobacteriochrome lineages with predictable photocycles
Identification of DXCF cyanobacteriochrome lineages with predictable photocycles
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DOI：
10.1039/c4pp00486h
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发表时间：
2015-01-01
影响因子：
3.1
通讯作者：
Lagarias, J. Clark
中科院分区：
文献类型：
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作者：
Rockwell, Nathan C.;Martin, Shelley S.;Lagarias, J. Clark
不同的生物体使用光敏色素光感受器来测量各自环境中红光与远红光的比例。除了红色/远红色光敏色素外，许多蓝藻细菌还含有远亲的蓝藻色素（CBCR）光传感器，它们也利用共价结合的线性四吡啶（十亿蛋白）发色团的光异构化来测量多种颜色的光。cbcr在近紫外和整个可见光谱中表现出显著的光周期变化。一类cbcr，以存在保守的Asp-Xaa-Cys-Phe （DXCF）基序或其变体为特征，包括具有紫/绿、蓝/绿、蓝/绿、蓝/黄、蓝/橙、绿/蓝和绿/绿光周期的成员。迄今为止，还没有证明从一级氨基酸序列预测这种光循环是可能的。研究人员利用位点定向诱变、系统发育分析和对6种新cbcr的表征来探索DXCF cbcr的结构/功能关系。这种方法定义了两组DXCF cbcr，它们具有专门的绿色/蓝色和蓝色/橙色光周期，可以从主序列数据中可靠地预测。这些知识促进了cbcr在合成光生物学应用中的使用，并为了解cbcr在蓝藻光生物学中的作用提供了方法。
Diverse organisms use phytochrome photoreceptors to measure the ratio of red to far-red light in their respective environments. In addition to red/far-red phytochromes, many cyanobacteria contain distantly related cyanobacteriochrome (CBCR) photosensors that also use photoisomerization of a covalently bound linear tetrapyrrole (bilin) chromophore to measure multiple colors of light. CBCRs exhibit a remarkable variety of photocycles spanning the near ultraviolet and the entire visible spectrum. One group of CBCRs, distinguished by the presence of a conserved Asp-Xaa-Cys-Phe (DXCF) motif or variations thereon, includes members with violet/green, blue/teal, blue/green, blue/yellow, blue/orange, green/blue and green/teal photocycles. To date, it has not proven possible to predict such photocycles from primary amino acid sequence. We here use site-directed mutagenesis, phylogenetic analysis, and characterization of six new CBCRs to probe structure/function relationships in DXCF CBCRs. This approach has defined two groups of DXCF CBCRs with specialized green/blue and blue/orange photocycles that are robustly predictable from primary sequence data. Such knowledge facilitates the use of CBCRs for synthetic photobiological applications and informs approaches to understand the roles of CBCRs in cyanobacterial photobiology.