The critical role of a hydrogen bond between Gln63 and Trp104 in the blue-light sensing BLUF domain that controls AppA activity
The critical role of a hydrogen bond between Gln63 and Trp104 in the blue-light sensing BLUF domain that controls AppA activity
复制标题
DOI：
10.1016/j.jmb.2007.02.087
复制
发表时间：
2007-05-18
影响因子：
5.6
通讯作者：
Takamiya, Ken-ichiro
中科院分区：
文献类型：
--
作者：
Masuda, Shinji;Tomida, Yoshiyuki;Takamiya, Ken-ichiro
AppA是一种新型蓝光受体，控制紫色细菌Rhodobacter sphaeroides的光合基因表达。光敏结构域BLUF的光循环反应是独特的，在这个意义上说，一些氢键重排伴随着只有轻微的结构变化的结合发色团。然而，活性位点周围的氢键网络的确切特征仍然是一些争议的主题。在这里，我们提出的生化和遗传证据表明，无论是Gln63或Trp104的BLUF结构域的活性位点是至关重要的光传感，这反过来又控制了抗阻遏活性的AppA。具体地，AppA的Q63L和W104A突变体在体内和体外对蓝光不敏感，并且它们的活性与光适应的野生型AppA的活性相似。基于前面描述的光谱和结构信息，我们得出结论，Gln63和Trp104之间的氢键的光依赖性形成和断裂是AppA的光敏感机制的关键。(C)2007爱思唯尔有限公司版权所有。
AppA is a novel blue-light receptor that controls photosynthetic gene expression in the purple bacterium Rhodobacter sphaeroides. The photocycle reaction of the light-sensing domain, BLUF, is unique in the sense that a few hydrogen bond rearrangements are accompanied by only slight structural changes of the bound chromophore. However, the exact features of the hydrogen bond network around the active site are still the subject of some controversy. Here we present biochemical and genetic evidence showing that either Gln63 or Trp104 in the active site of the BLUF domain is crucial for light sensing, which in turn controls the antirepressor activity of AppA. Specifically, the Q63L and W104A mutants of AppA are insensitive to blue light in vivo and in vitro, and their activity is similar to that of the lightadapted wild-type AppA. Based on spectroscopic and structural information described previously, we conclude that light-dependent formation and breakage of the hydrogen bond between Gln63 and Trp104 are critical for the light-sensing mechanism of AppA. (C) 2007 Elsevier Ltd. All rights reserved.