DNA-binding properties of a cGMP-binding CRP homologue that controls development of metabolically dormant cysts of Rhodospirillum centenum.
DNA-binding properties of a cGMP-binding CRP homologue that controls development of metabolically dormant cysts of Rhodospirillum centenum.
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一种 cGMP 结合 CRP 同源物的 DNA 结合特性，可控制 Centenum 红螺菌代谢休眠包囊的发育。
DOI：
10.1099/mic.0.000172
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
Bauer,CarlE
中科院分区：
文献类型：
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作者：
Roychowdhury,Sugata;Dong,Qian;Bauer,CarlE
百蕊杜鹃（Rhodocellum centenum）利用3′，5 ′-环鸟苷一磷酸（cGMP）作为信使来调节抗脱水孢囊的发育。在这项研究中，我们证明了thatgcyA，gcyBandgcyC，编码鸟苷酸环化酶的推定亚基，增加表达从8到500倍，当细胞从营养过渡到囊肿生长阶段。这种诱导在cGMP合成缺陷的菌株中或包含编码大肠杆菌代谢物阻遏蛋白（CRP）的cGMP结合同源物的cgrA缺失的菌株中没有发生。我们还证明了cgrA在cGMP存在的情况下自动诱导其自身的表达，这表明当细胞经历包囊化时，前馈回路用于增加cGMP的产生。对gcyB上游基因内区域的检查显示了一个与弗罗姆的CRP共有序列相同的序列。杆菌DNase I和荧光各向异性分析表明，CgrA与该靶序列以1：2的蛋白质：cGMP比例结合，Kd为61 nM。 这与cAMP存在下的CgrA相反，其显示Kd为1795 nM。 因此，CgrA构成CRP的新变体，其利用cGMP来调节cGMP合酶的产生以控制囊肿发育。
Rhodospirillum centenumutilizes 3′,5′-cyclic guanosine monophosphate (cGMP) as a messenger to regulate development of desiccation-resistant cysts. In this study, we demonstrated thatgcyA, gcyBandgcyC,coding for putative subunits of a guanylyl cyclase, increase expression from 8- to 500-fold when cells transition from vegetative to cyst phases of growth. This induction did not occur in a strain that is defective in cGMP synthesis or in a strain that contains a deletion ofcgrAthat codes for a cGMP-binding homologue ofEscherichia colicatabolite repressor protein (CRP). We also demonstrated thatcgrAauto-induces its own expression in the presence of cGMP, indicating that a feed-forward loop is used to ramp up cGMP production as cells undergo encystment. Inspection of an intragenic region upstream ofgcyBrevealed a sequence that is identical to the CRP consensus sequence fromE. coli. DNase I and fluorescence anisotropy analyses demonstrated that CgrA bound to this target sequence at a protein : cGMP ratio of 1 : 2 withKd∼61 nM. This was in contrast to CgrA in the presence of cAMP, which exhibitedKd∼1795 nM. CgrA thus constitutes a novel variant of CRP that utilizes cGMP to regulate production of cGMP synthase for the control of cyst development.