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Title: Temperature and Mg2+ sensing by a novel PhoP-PhoQ two-component system for regulation of virulence in Edwardsiella tarda
Authors: Chakraborty, S. 
Li, M. 
Chatterjee, C. 
Sivaraman, J. 
Leung, K.Y.
Mok, Y.-K. 
Issue Date: 10-Dec-2010
Citation: Chakraborty, S., Li, M., Chatterjee, C., Sivaraman, J., Leung, K.Y., Mok, Y.-K. (2010-12-10). Temperature and Mg2+ sensing by a novel PhoP-PhoQ two-component system for regulation of virulence in Edwardsiella tarda. Journal of Biological Chemistry 285 (50) : 38876-38888. ScholarBank@NUS Repository.
Abstract: The PhoP-PhoQ two-component system is commonly used by bacteria to sense environmental factors. Here we show that the PhoP-PhoQ system of Edwardsiella tarda detects changes in environmental temperature and Mg2+ concentration as well as regulates the type III and VI secretion systems through direct activation of esrB. Protein secretion is activated from 23 to 35°C or at low Mg2+ concentrations, but it is suppressed at or below 20°C, at or above 37°C, or at high Mg2+ concentrations. The effects of temperature and Mg2+ concentration are additive. The PhoQ sensor domain has a low Tm of 37.9°C, and it detects temperatures through a conformational change of its secondary structure. Mutation of specific Pro or Thr residues increased the stability of the PhoQ sensor drastically, altering its temperature-sensing ability. The PhoQ sensor detects Mg2+ concentration through the direct binding of Mg2+ to a cluster of acidic residues (DDDSAD) and through changes that likely affect its tertiary structure. Here, we describe for the first time the use of PhoP-PhoQ as a temperature sensor for bacterial virulence control. © 2010 by The American Society for Biochemistry and Molecular Biology, Inc.
Source Title: Journal of Biological Chemistry
ISSN: 00219258
DOI: 10.1074/jbc.M110.179150
Appears in Collections:Staff Publications

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