Steric hindrance regulation of the Pseudomonas aeruginosa amidase operon
Steric hindrance regulation of the Pseudomonas aeruginosa amidase operon
复制标题
DOI：
10.1074/jbc.m000813200
复制
发表时间：
2000-09-29
影响因子：
4.8
通讯作者：
Drew, RE
中科院分区：
文献类型：
--
作者：
Norman, RA;Poh, CL;Drew, RE
铜绿假单胞菌酰胺酶操纵子的表达受配体传感器和负调节因子AmiC以及转录抗终止因子激活因子AmiR的控制。我们已经通过增加反式AmiR的产生滴定了体内AmiC抑制活性，并通过空间位阻机制显示了AmiC对AmiR抗终止活性的调节。在存在共阻遏物丁酰胺的情况下，我们已经分离出稳定的AmiC.AmiR复合物，将诱导配体乙酰胺添加到复合物中触发分子开关，引起复合物解离并释放AmiR。AmiC.Amir丁酰胺复合物显示出乙酰胺依赖性、序列特异性RNA结合活性，计算出Ami.R RNA相互作用的K（d）为1.0 nM。结果表明，酰胺酶操纵子的表达是由一种新型的信号转导系统控制的，在该系统中，位点特异性RNA结合激活剂的活性通过螯合机制进行调节。
Expression of the amidase operon of Pseudomonas aeruginosa is controlled by AmiC, the ligand sensor and negative regulator, and AmiR the transcription antitermination factor activator. We have titrated out AmiC repression activity in vivo by increased AmiR production in trans and shown AmiC regulation of the antitermination activity of AmiR by a steric hindrance mechanism. In the presence of the co-repressor butyramide we have isolated a stable AmiC.AmiR complex, Addition of the inducing ligand acetamide to the complex trips the molecular switch, causing complex dissociation and release of AmiR. The AmiC.AmiR butyramide complex exhibits acetamide-dependent, sequence-specific RNA binding activity and a K(d) of 1.0 nM has been calculated for the Ami.R RNA interaction. The results show that amidase operon expression is controlled by a novel type of signal transduction system in which activity of a site-specific RNA binding activator is regulated via a sequestration mechanism.