Chromophorylation of cyanobacteriochrome Slr1393 from Synechocystis sp PCC 6803 is regulated by protein Slr2111 through allosteric interaction
Chromophorylation of cyanobacteriochrome Slr1393 from Synechocystis sp PCC 6803 is regulated by protein Slr2111 through allosteric interaction
复制标题
集胞藻 PCC 6803 的蓝细菌色素 Slr1393 的发色由蛋白质 Slr2111 通过变构相互作用调节
DOI：
10.1074/jbc.ra118.003830
复制
发表时间：
2018
影响因子：
4.8
通讯作者：
Zhao Kai-Hong
中科院分区：
文献类型：
--
作者：
He Qi;Tang Qi-Ying;Sun Ya-Fang;Zhou Ming;Gaertner Wolfgang;Zhao Kai-Hong
蓝细菌色素（CBCRs）是蓝细菌中的光致变色蛋白，作为光传感器。CBCRs作为发色团与胆磷脂结合并感知几乎整个可见光谱，但CBCRs的发色磷酸化调控尚不清楚。Slr1393 fromSynechocystissp。PCC 6803是一种含有三个连续GAF （cGMP磷酸二酯酶、腺苷酸环化酶和FhlA蛋白）结构域的CBCR，其中只有第三个结构域（Slr1393g3）可以被藻蓝胆素铬化。synechocystissp的Slr2111蛋白。PCC 6803在其N端包含一个功能未知的胱硫氨酸β-合成酶（CBS）结构域对。CBS结构域通常通过结合核苷酸作为细胞能量状态的传感器。在这项工作中，我们证明了Slr2111在体内和体外与slr1393强烈相互作用，并以1:1的摩尔比生成复合物。这种紧密的相互作用抑制Slr1393g3的染色质磷酸化，即使存在发色团。相反，Slr1393的复合体稳定性和染色质磷酸化是通过核苷酸（ATP， ADP， AMP）以不同的亲和力结合到Slr2111的CBS结构域来调节的。结果表明，Slr2111的Asp-53和Arg-97残基参与了核苷酸结合。当ATP与Slr2111结合时，两种蛋白之间的关联减弱，Slr1393的色素磷酸化被激活。相反，AMP与Slr2111结合会导致更强的结合，从而抑制色素磷酸化。综上所述，Slr2111作为细胞能量状态的传感器，调节Slr1393的色素磷酸化，从而发挥其作为光驱动组氨酸激酶的功能。
Cyanobacteriochromes (CBCRs) are photochromic proteins in cyanobacteria that act as photosensors. CBCRs bind bilins as chromophores and sense nearly the entire visible spectrum of light, but the regulation of the chromophorylation of CBCRs is unknown. Slr1393 fromSynechocystissp. PCC 6803 is a CBCR containing three consecutive GAF (cGMP phosphodiesterase, adenylyl cyclase, and FhlA protein) domains, of which only the third one (Slr1393g3) can be phycocyanobilin-chromophorylated. The protein Slr2111 fromSynechocystissp. PCC 6803 includes a cystathionine β-synthase (CBS) domain pair of an as yet unknown function at its N terminus. CBS domains are often characterized as sensors of cellular energy status by binding nucleotides. In this work, we demonstrate that Slr2111 strongly interacts with Slr1393in vivoandin vitro, which generates a complex in a 1:1 molar ratio. This tight interaction inhibits the chromophorylation of Slr1393g3, even if the chromophore is present. Instead, the complex stability and thereby the chromophorylation of Slr1393 are regulated by the binding of nucleotides (ATP, ADP, AMP) to the CBS domains of Slr2111 with varying affinities. It is demonstrated that residues Asp-53 and Arg-97 of Slr2111 are involved in nucleotide binding. While ATP binds to Slr2111, the association between the two proteins gets weaker and chromophorylation of Slr1393 are enabled. In contrast, AMP binding to Slr2111 leads to a stronger association, thereby inhibiting the chromophorylation. It is concluded that Slr2111 acts as a sensor of the cellular energy status that regulates the chromophorylation of Slr1393 and thereby its function as a light-driven histidine kinase.