Phosphate flow in the chemotactic response system of Helicobacter pylori
Phosphate flow in the chemotactic response system of Helicobacter pylori
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DOI：
10.1099/mic.0.28217-0
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发表时间：
2005-10-01
期刊：
影响因子：
2.8
通讯作者：
Beier, D
中科院分区：
文献类型：
--
作者：
Jiménez-Pearson, MA;Delany, I;Beier, D
众所周知，运动性是人类胃部病原体幽门螺杆菌的一个重要毒力特征。因此，趋化性有助于幽门螺杆菌定植动物感染模型的能力。幽门螺杆菌的趋化信号转导在几个方面不同于肠道细菌范例。除了一个单独的Chey反应调节蛋白(CheY1)，H.py/或含有一个类似Chey的受体结构域(CheY2)，它在C端与组氨酸激酶CheA融合。此外，幽门螺杆菌基因组编码由N端咀嚼样区和C端接收区组成的三个CHIV蛋白，而趋化基因CheB、Cher和CHEZ没有同源基因。为了深入了解控制幽门螺杆菌趋化反应的机制，我们在体外研究了纯化的两组分信号模块之间的磷酸转移反应。我们证明了CheY1和CheY2都被CheA磷酸化，与P相似，并且三个Chev蛋白与P相似地介导了CheA的去磷酸化，但与CheY1和CheY2相比，效率明显降低。此外，我们的数据表明CheY1类似于P对CheAY2的逆磷酸化，提示CheY2作为一个磷酸汇聚调节CheY1类似于P的半衰期。
It is well established that motility is an essential virulence trait of the human gastric pathogen Helicobacter pylori. Accordingly, chemotaxis contributes to the ability of H. pylori to colonize animal infection models. Chemotactic signal transcluction in H. pylori differs from the enterobacterial paradigm in several respects. In addition to a separate CheY response regulator protein (CheY1), H. py/oricontains a CheY-like receiver domain (CheY2) which is C-terminally fused to the histidine kinase CheA. Furthermore, the genome of H. pylori encodes three CheV proteins consisting of an N-terminal CheW-like domain and a C-terminal receiver domain, while there are no orthologues of the chemotaxis genes cheB, cheR and cheZ. To obtain insight into the mechanisms controlling the chemotactic response of H. pylori, we investigated the phosphotransfer reactions between the purified two-component signalling modules in vitro. We demonstrate that both CheY1 and CheY2 are phosphorylated by CheA similar to P and that the three CheV proteins mediate the dephosphorylation of CheA similar to P, but with a clearly reduced efficiency as compared to CheY1 and CheY2. Furthermore, our data indicate retrophosphorylation of CheAY2 by CheY1 similar to P, suggesting a role of CheY2 as a phosphate sink to modulate the half-life of CheY1 similar to P.