Leucine alters the interaction of the leucine-responsive regulatory protein (Lrp) with the fim switch to stimulate site-specific recombination in Escherichia coli.
Leucine alters the interaction of the leucine-responsive regulatory protein (Lrp) with the fim switch to stimulate site-specific recombination in Escherichia coli.
复制标题
亮氨酸改变亮氨酸响应调节蛋白 (Lrp) 与 fim 开关的相互作用，以刺激大肠杆菌中的位点特异性重组。
DOI：
10.1046/j.1365-2958.1998.00720.x
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发表时间：
1998
影响因子：
3.6
通讯作者：
Blomfield,IC
中科院分区：
文献类型：
--
作者：
Roesch,PL;Blomfield,IC
亮氨酸应答调节蛋白（Leucine-responsive regulatory protein，Lrp）是一种全局调节因子，控制大肠杆菌中大量操纵子的表达。Lrp可作为转录的抑制因子或激活因子，其作用可被外源亮氨酸增强、抑制或不受影响。1型菌毛在E.大肠杆菌提供了一个独特的系统，其中研究亮氨酸对Lrp的影响，因为它是唯一已知的Lrp是正调节剂和亮氨酸增强这种作用的例子。先前的研究确定Lrp以高亲和力结合到fimswitch内的两个位点（fimsites 1和2），并且结合到这些位点刺激重组。在这里，它表明，即使亮氨酸刺激thefimswitchin体内，但它仍然会导致轻微减少Lrp结合thefimswitchin体外。这些相互矛盾的结果是可以解释的发现，Lrp结合到第三个区域附近的fimsites 1和2抑制重组。根据该模型，亮氨酸通过选择性地破坏Lrp与该新表征区域的结合来刺激重组，而对Lrp与fimsites 1和2的结合几乎没有或没有影响。
The leucine‐responsive regulatory protein (Lrp) is a global regulator that controls the expression of numerous operons inEscherichia coli. Lrp can act as a repressor or as an activator of transcription with its effects being potentiated, repressed or unaffected by the presence of exogenous leucine. The phase variation of type 1 fimbria inE. coliprovides a unique system in which to investigate the effects of leucine on Lrp, as it is the only known example in which Lrp is a positive regulator and leucine potentiates this effect. Previous studies determined that Lrp binds with high affinity to two sites within thefimswitch (fimsites 1 and 2), and binding to these sites stimulates recombination. Here, it is shown that, even though leucine stimulates thefimswitchin vivo, it nevertheless causes a slight decrease in Lrp binding to thefimswitchin vitro. These contradictory results are explicable by the finding that Lrp binding to a third region adjacent tofimsites 1 and 2 inhibits recombination. According to this model, leucine stimulates recombination by selectively disrupting Lrp binding to this newly characterized region, while having little or no effect on Lrp binding tofimsites 1 and 2.