Multiple allosteric effectors control the affinity of DasR for its target sites.
Multiple allosteric effectors control the affinity of DasR for its target sites.
复制标题
DOI：
10.1016/j.bbrc.2015.06.152
复制
发表时间：
2015-08
影响因子：
3.1
通讯作者：
Elodie Tenconi;Mia Urem;M. Świątek-Połatyńska;F. Titgemeyer;Y. Muller;G. V. van Wezel;S. Rigali
中科院分区：
文献类型：
--
作者：
Elodie Tenconi;Mia Urem;M. Świątek-Połatyńska;F. Titgemeyer;Y. Muller;G. V. van Wezel;S. Rigali
全球转录调节因子DasR将n -乙酰氨基葡萄糖（GlcNAc）的利用与模式放线菌链霉菌的形态和化学分化的开始联系起来。先前的研究表明，葡萄糖胺-6-磷酸（GlcN-6P）作为一种变弹性效应物，使DasR与其操作位点（称为DasR响应元件）的结合失效，并允许DasR控制/ glcnac依赖基因的抑制。揭示DasR控制ss的机制。我们用组氨酸标记的DasR蛋白进行了一系列的电迁移性转移实验，结果表明n -乙酰氨基葡萄糖-6-磷酸（GlcNAc-6P）也可以抑制DasR-再复合物的形成，甚至可能比GlcN-6P更有效。在aga突变体中，由于缺乏GlcNAc-6P脱氨酶活性，因此积累了GlcNAc-6P，因此DasR抑制的nagka启动子的高组成活性进一步证实了GlcNAc-6P确实是DasR的有效变构效应。此外，我们还观察到高浓度的有机或无机磷酸盐增强了DasR与其识别位点的结合，这表明细胞的代谢状态可以决定DasRin在体内的选择性，从而影响其调控子的表达。
The global transcriptional regulator DasR connects N-acetylglucosamine (GlcNAc) utilization to the onset of morphological and chemical differentiation in the model actinomyceteStreptomyces coelicolor. Previous work revealed that glucosamine-6-phosphate (GlcN-6P) acts as an allosteric effector which disables binding by DasR to its operator sites (calleddre, for DasR responsive element) and allows derepression of DasR-controlled/GlcNAc-dependent genes. To unveil the mechanism by which DasR controlsS. coelicolordevelopment, we performed a series of electromobility shift assays with histidine-tagged DasR protein, which suggested that N-acetylglucosamine-6-phosphate (GlcNAc-6P) could also inhibit the formation of DasR-drecomplexes and perhaps even more efficiently than GlcN-6P. The possibility that GlcNAc-6P is indeed an efficient allosteric effector of DasR was further confirmed by the high and constitutive activity of the DasR-repressednagKApromoter in thenagA mutant, which lacks GlcNAc-6P deaminase activity and therefore accumulates GlcNAc-6P. In addition, we also observed that high concentrations of organic or inorganic phosphate enhanced binding of DasR to its recognition site, suggesting that the metabolic status of the cell could determine the selectivity of DasRin vivo, and hence its effect on the expression of its regulon.