PDF(Pubmed)
Abstract：
Two-component regulatory systems (TCSs) are a major mechanism used by bacteria to sense and respond to their environments. Many of the same TCSs are used by biologically diverse organisms with different regulatory needs, suggesting that the functions of TCS must evolve. To explore this topic, we analysed the amino acid sequence divergence patterns of a large set of broadly conserved TCS across different branches of Enterobacteriaceae, a family of Gram-negative bacteria that includes biomedically important genera such as Salmonella, Escherichia, Klebsiella and others. Our analysis revealed trends in how TCS sequences change across different proteins or functional domains of the TCS, and across different lineages. Based on these trends, we identified individual TCS that exhibit atypical evolutionary patterns. We observed that the relative extent to which the sequence of a given TCS varies across different lineages is generally well conserved, unveiling a hierarchy of TCS sequence conservation with EnvZ/OmpR as the most conserved TCS. We provide evidence that, for the most divergent of the TCS analysed, PmrA/PmrB, different alleles were horizontally acquired by different branches of this family, and that different PmrA/PmrB sequence variants have highly divergent signal-sensing domains. Collectively, this study sheds light on how TCS evolve, and serves as a compendium for how the sequences of the TCS in this family have diverged over the course of evolution.
摘要：
双组分调节系统（TCS）是细菌用于感知和响应其环境的主要机制。许多相同的TCS被具有不同监管需求的生物多样性生物体使用，这表明TCS的功能必须演变。为了探讨这个话题，我们分析了肠杆菌科不同分支的大量广泛保守的TCS的氨基酸序列差异模式，一个革兰氏阴性细菌家族，包括重要的生物医学属，如沙门氏菌，埃希氏菌,克雷伯氏菌和其他人。我们的分析揭示了TCS序列如何在TCS的不同蛋白质或功能域之间变化的趋势，跨越不同的血统。基于这些趋势,我们确定了表现出非典型进化模式的个体TCS.我们观察到，给定TCS的序列在不同谱系之间变化的相对程度通常是保守的，揭示了TCS序列守恒的层次结构，其中EnvZ/OmpR是最守恒的TCS。我们提供的证据表明,对于分析的最不同的TCS，PmrA/PmrB,该家族的不同分支水平获得了不同的等位基因，并且不同的PmrA/PmrB序列变体具有高度不同的信号感应域。总的来说，这项研究揭示了TCS是如何进化的，并作为该家族中TCS序列在进化过程中如何分化的纲要。
