A family of positive regulators related to the Pseudomonas putida TOL plasmid XylS and the Escherichia coli AraC activators.
A family of positive regulators related to the Pseudomonas putida TOL plasmid XylS and the Escherichia coli AraC activators.
复制标题
与恶臭假单胞菌 TOL 质粒 XylS 和大肠杆菌 AraC 激活剂相关的正调节因子家族。
DOI：
10.1093/nar/18.8.2149
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发表时间：
1990
影响因子：
14.9
通讯作者：
K. N. Timmis
中科院分区：
文献类型：
--
作者：
Juan L. Ramos;Fernando Rojo;Luming Zhou;K. N. Timmis
XylS家族由至少8种不同的转录调节因子组成。这些蛋白质中的六种是大肠杆菌、恶臭假单胞菌和胡萝卜软腐欧文氏菌中碳源（苯甲酸盐和糖）的催化活性的正调节剂，其中两种参与大肠杆菌和小肠结肠炎耶尔森氏菌的发病机制。基于蛋白质比对，该家族的成员在C-末端表现出很长的同源性。参与碳源催化的调节子仅在效应子存在下刺激从其各自调节的启动子的转录。在两个调节子中，在非同源N-末端的突变改变了对效应子的亲和力和特异性，而在保守C-末端部分的突变降低了从其相应的调节启动子的转录激活。因此，这是可能的，在这个家族的调节器的可变N-末端包含的基序参与效应识别，而C-末端参与DNA结合。这些蛋白质似乎有共同的祖先，并可能通过类似的折叠模式，通过类似的正调控机制发挥作用。
The XylS family consists of a least 8 different transcriptional regulators. Six of these proteins are positive regulators for the catabolism of carbon sources (benzoate and sugars) in Escherichia coli, Pseudomonas putida and Erwinia carotovora, and two of them are involved in pathogenesis in Escherichia coli and Yersinia enterocolitica. Based on protein alignments, the members of this family exhibit a long stretch of homology at the C-terminal end. The regulators involved in the catabolism of carbon sources stimulate transcription from their respectively regulated promoters only in the presence of effectors. In two of the regulators, mutations at the non-homologous N-terminus alter affinity and specificity for effectors while mutations at the conserved C-terminus part decrease activation of transcription from their corresponding regulated promoters. It is thus probable that the variable N-terminus end in this family of regulators contains the motif involved in effector recognition, while the C-terminal end is involved in DNA-binding. These proteins seem to be related by common ancestry and may act through similar mechanisms of positive regulation effected through similar folding patterns.