Characterization of Mycobacterium tuberculosis RV3676 (CRPMT), a cyclic AMP receptor protein-like DNA binding protein
Characterization of Mycobacterium tuberculosis RV3676 (CRPMT), a cyclic AMP receptor protein-like DNA binding protein
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DOI：
10.1128/jb.187.22.7795-7804.2005
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发表时间：
2005-11-01
影响因子：
3.2
通讯作者：
McDonough, KA
中科院分区：
文献类型：
--
作者：
Bai, GC;McCue, LA;McDonough, KA
环腺苷酸（cAMP）在结核分枝杆菌中的功能知之甚少，尽管它能够编码15种腺苷酸环化酶和10种cNMP结合蛋白。M.结核病Rv3676，我们已经指定CRPMt，被预测为cAMP依赖性转录因子。在这项研究中，我们的特点CRPMt的相互作用与DNA和cAMP，使用实验和计算方法。我们使用吉布斯采样来定义一个CRPMt DNA基序，类似于大肠杆菌的cAMP受体蛋白（CRP）结合基序模型。CRPMt结合位点被确定在总共73个启动子区域中调节M.结核病基因组，这是正在探索的调节子。特异性CRPMt结合导致DNA弯曲，并且结合位点中高度保守的核苷酸的取代导致与CRPMt的结合完全丧失。cAMP增强CRPMt结合DNA的能力，并引起CRP构象的变构改变。这些结果为cAMP与M中的转录因子结合提供了第一个直接证据。提示cAMP信号转导在M.结核病和牵连CRPMt作为一个cAMP反应的全球监管机构。
Little is known about cyclic AMP (cAMP) function in Mycobacterium tuberculosis, despite its ability to encode 15 adenylate cyclases and 10 cNMP-binding proteins. M. tuberculosis Rv3676, which we have designated CRPMt, is predicted to be a cAMP-dependent transcription factor. In this study, we characterized CRPMt's interactions with DNA and cAMP, using experimental and computational approaches. We used Gibbs sampling to define a CRPMt DNA motif that resembles the cAMP receptor protein (CRP) binding motif model for Escherichia coli. CRPMt binding sites were identified in a total of 73 promoter regions regulating 114 genes in the M. tuberculosis genome, which are being explored as a regulon. Specific CRPMt binding caused DNA bending, and the substitution of highly conserved nucleotides in the binding site resulted in a complete loss of binding to CRPMt. cAMP enhanced CRPMt's ability to bind DNA and caused allosteric alterations in CRP,, conformation. These results provide the first direct evidence for cAMP binding to a transcription factor in M. tuberculosis, suggesting a role for cAMP signal transduction in M. tuberculosis and implicating CRPMt as a cAMP-responsive global regulator.