An oxygen-sensing diguanylate cyclase and phosphodiesterase couple for c-di-GMP control.
An oxygen-sensing diguanylate cyclase and phosphodiesterase couple for c-di-GMP control.
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DOI：
10.1021/bi901409g
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发表时间：
2009-09
期刊：
影响因子：
2.9
通讯作者：
J. Tuckerman;G. Gonzalez;E. H. Sousa;Xuehua Wan;J. Saito;Maqsudul Alam;M. Gilles‐Gonzalez
中科院分区：
文献类型：
--
作者：
J. Tuckerman;G. Gonzalez;E. H. Sousa;Xuehua Wan;J. Saito;Maqsudul Alam;M. Gilles‐Gonzalez
ggdef类二胍酸环化酶和eal类磷酸二酯酶之间普遍观察到的感觉结构域耦合，长期以来表明c-二gmp合成和降解酶可以感知环境信号。然而，相对较少的信号配体已被确定为这些传感器，甚至更少的例子表明，通过配体在体外切换。在这里，我们描述了一个大肠杆菌双基因操纵子，dosCP，用于氧控制c-二gmp。在这个操纵子中，编码氧感应c-二gmp磷酸二酯酶Ec Dos（此处重命名为Ec DosP）的基因紧随其后，并与编码二胍酸环化酶的基因（此处称为DosC）翻译偶联。我们提出了DosC的第一个特征，并详细研究了DosP的配体剂量响应。我们的研究结果表明，DosC是一种珠蛋白偶联传感器，具有极性但可接近的血红素口袋，其结合氧的K(d)为20微米。DosP活化对氧浓度增加的响应是其配体饱和度的复杂函数，因此超过80%的活化发生在超过30%空气饱和度（氧bb0 75微米）的溶液中。最后，我们发现DosP和DosC结合成一个功能复合物。我们得出结论，dosCP操纵子编码两个氧传感器，这两个氧传感器协同控制c-di-GMP的产生和去除。
A commonly observed coupling of sensory domains to GGDEF-class diguanylate cyclases and EAL-class phosphodiesterases has long suggested that c-di-GMP synthesizing and degrading enzymes sense environmental signals. Nevertheless, relatively few signal ligands have been identified for these sensors, and even fewer instances of in vitro switching by ligand have been demonstrated. Here we describe an Escherichia coli two-gene operon, dosCP, for control of c-di-GMP by oxygen. In this operon, the gene encoding the oxygen-sensing c-di-GMP phosphodiesterase Ec Dos (here renamed Ec DosP) follows and is translationally coupled to a gene encoding a diguanylate cyclase, here designated DosC. We present the first characterizations of DosC and a detailed study of the ligand-dose response of DosP. Our results show that DosC is a globin-coupled sensor with an apolar but accessible heme pocket that binds oxygen with a K(d) of 20 microM. The response of DosP activation to increasing oxygen concentration is a complex function of its ligand saturation such that over 80% of the activation occurs in solutions that exceed 30% of air saturation (oxygen >75 microM). Finally, we find that DosP and DosC associate into a functional complex. We conclude that the dosCP operon encodes two oxygen sensors that cooperate in the controlled production and removal of c-di-GMP.