Phosphorylation stimulates the cooperative DNA-binding properties of the transcription factor OmpR
Phosphorylation stimulates the cooperative DNA-binding properties of the transcription factor OmpR
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DOI：
10.1073/pnas.94.7.2828
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发表时间：
1997-04-01
影响因子：
11.1
通讯作者：
Igo, MM
中科院分区：
文献类型：
--
作者：
Huang, KJ;Lan, CY;Igo, MM
大肠杆菌K-12的双组分调节蛋白OmpR和EnvZ调节主要外膜孔蛋白OmpF的表达，OmpR是一种dna结合蛋白，参与OmpF转录的阳性和阴性控制，EnvZ是一种组氨酸激酶，响应环境信号使OmpR磷酸化。我们使用DNA迁移延迟分析来检测OmpR和磷酸化形式的OmpR （OmpR- p）与OmpR启动子上游的调控区域的相互作用。我们的结果表明，OmpR与该调控区域的结合是合作的，磷酸化显著地刺激了这些合作相互作用。此外，尽管磷酸化增加了OmpR与单个OmpR结合位点的内在结合，磷酸化在OmpR调控中的主要作用是促进在相邻位点结合的OmpR分子之间的合作相互作用。基于这些结果，我们提出了一个模型来解释OmpR的磷酸化如何刺激ompF调控区域特定位点的占用，从而在适当的环境条件下导致ompF转录的激活或抑制。
The two-component regulatory proteins OmpR and EnvZ of Escherichia coli K-12 regulate expression of the major outer membrane porin protein, OmpF, OmpR is a DNA-binding protein that is involved in both the positive and negative control of ompF transcription, EnvZ is a histidine kinase that phosphorylates OmpR in response to environmental signals. We used DNA migration retardation analysis to examine the interactions of OmpR and the phosphorylated form of OmpR (OmpR-P) with the regulatory region immediately upstream of the ompF promoter, Our results indicate that the binding of OmpR to this regulatory region is cooperative and that phosphorylation significantly stimulates these cooperative interactions, Moreover, although phosphorylation increases the intrinsic binding of OmpR to a single OmpR-binding site, the primary role of phosphorylation in ompF regulation is to facilitate cooperative interactions between OmpR molecules bound at adjacent sites. Based on these results, we propose a model to explain how the phosphorylation of OmpR could stimulate the occupancy of specific sites in the ompF regulatory region, thereby resulting In the activation or repression of ompF transcription under the appropriate environmental conditions.