Alkali Metals in Addition to Acidic pH Activate the EvgS Histidine Kinase Sensor in Escherichia coli
Alkali Metals in Addition to Acidic pH Activate the EvgS Histidine Kinase Sensor in Escherichia coli
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DOI：
10.1128/jb.01742-14
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发表时间：
2014-09-01
影响因子：
3.2
通讯作者：
Utsumi, Ryutaro
中科院分区：
文献类型：
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作者：
Eguchi, Yoko;Utsumi, Ryutaro
细菌中的双组分信号转导系统(TCSs)感知环境压力，并通过磷继电器传递信息，以调节多种细胞功能以适应环境。EvgS/EVGA系统是一种对大肠杆菌细胞具有耐酸性的TCS。EvgS传感器的激活启动了转录因子EVGA、YdeO和Gade的级联反应，这些转录因子诱导了一大群耐酸基因的表达。我们寻找激活EvgS的信号，发现除了低pH值外，高浓度的碱金属(Na+，K+)对激活是必不可少的。EvgS是一种组氨酸激酶，在其N端有一个大的周质感受器区域，由两个串联的PBPB(细菌周质溶质结合蛋白)结构域组成。EvgS的周质感受区是激活EvgS所必需的，位于第一个PBPB结构域的Leu152参与了激活。此外，EvgS和PhoQ组氨酸激酶的嵌合体表明，碱金属在周质感受器区域被感知，而连接跨膜区和组氨酸激动域的细胞质连接器域是低pH感知所必需的。
Two-component signal transduction systems (TCSs) in bacteria perceive environmental stress and transmit the information via phosphorelay to adjust multiple cellular functions for adaptation. The EvgS/EvgA system is a TCS that confers acid resistance to Escherichia coli cells. Activation of the EvgS sensor initiates a cascade of transcription factors, EvgA, YdeO, and GadE, which induce the expression of a large group of acid resistance genes. We searched for signals activating EvgS and found that a high concentration of alkali metals (Na+, K+) in addition to low pH was essential for the activation. EvgS is a histidine kinase, with a large periplasmic sensor region consisting of two tandem PBPb (bacterial periplasmic solute-binding protein) domains at its N terminus. The periplasmic sensor region of EvgS was necessary for EvgS activation, and Leu152, located within the first PBPb domain, was involved in the activation. Furthermore, chimeras of EvgS and PhoQ histidine kinases suggested that alkali metals were perceived at the periplasmic sensor region, whereas the cytoplasmic linker domain, connecting the transmembrane region and the histidine kinase domain, was required for low-pH perception.