首页> 外文期刊>Biochimica et Biophysica Acta. General Subjects >Molecular modeling and functional analysis of the AtoS-AtoC two-component signal transduction system of Escherichia coli.
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Molecular modeling and functional analysis of the AtoS-AtoC two-component signal transduction system of Escherichia coli.

机译:大肠杆菌AtoS-AtoC两组分信号转导系统的分子建模和功能分析。

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The AtoS-AtoC two-component signal transduction system positively regulates the expression of the atoDAEB operon in Escherichia coli. Upon acetoacetate induction, AtoS sensor kinase autophosphorylates and subsequently phosphorylates, thereby activating, the response regulator AtoC. In a previous work we have shown that AtoC is phosphorylated at both aspartate 55 and histidine73. In this study, based on known three-dimensional structures of other two component regulatory systems, we modeled the 3D-structure of the receiver domain of AtoC in complex with the putative dimerization/autophosphorylation domain of the AtoS sensor kinase. The produced structural model indicated that aspartate 55, but not histidine 73, of AtoC is in close proximity to the conserved, putative phosphate-donor, histidine (H398) of AtoS suggesting that aspartate 55 may be directly involved in the AtoS-AtoC phosphate transfer. Subsequent biochemical studies with purified recombinant proteins showed that AtoC mutants with alterationsof aspartate 55, but not histidine 73, were unable to participate in the AtoS-AtoC phosphate transfer in support of the modeling prediction. In addition, these AtoC mutants displayed reduced DNA-dependent ATPase activity, although their ability to bind their target DNA sequences in a sequence-specific manner was found to be unaltered.
机译:AtoS-AtoC两组分信号转导系统可正向调节atoDAEB操纵子在大肠杆菌中的表达。乙酰乙酸诱导后,AtoS传感器激酶自磷酸化,随后磷酸化,从而激活应答调节剂AtoC。在以前的工作中,我们表明AtoC在天冬氨酸55和组氨酸73处均被磷酸化。在这项研究中,基于其他两个成分调控系统的已知三维结构,我们对AtoC受体域的3D结构与AtoS传感器激酶的假定二聚/自磷酸化域进行了复杂的建模。产生的结构模型表明,AtoC的天冬氨酸55,而不是组氨酸73与保守的AtoS假定的磷酸盐供体组氨酸(H398)密切相关,表明天冬氨酸55可能直接参与了AtoS-AtoC磷酸盐的转移。随后用纯化的重组蛋白进行的生化研究表明,具有天冬氨酸55而不是组氨酸73改变的AtoC突变体无法参与AtoS-AtoC磷酸转移,从而支持建模预测。另外,尽管发现这些AtoC突变体以序列特异性方式结合其靶DNA序列的能力没有改变,但它们显示出降低的DNA依赖性ATP酶活性。

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