J. Bacteriol. doi:10.1128/JB.00049-07
Copyright (c) 2007, American Society for Microbiology and/or the Listed Authors/Institutions. All Rights Reserved.
Crystal Structures of the Receiver Domain of Response Regulator PhoP from Escherichia coli in the Absence and Presence of the Phosphoryl Analog Beryllofluoride
Priti Bachhawat
and
Ann M. Stock*
Center for Advanced Biotechnology and Medicine, Department of Biochemistry, and Howard Hughes Medical Institute, University of Medicine and Dentistry of New Jersey - Robert Wood Johnson Medical School, Piscataway, New Jersey 08854
* To whom correspondence should be addressed. Email:
stock{at}cabm.rutgers.edu.
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Abstract |
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The response regulator PhoP is part of the PhoQ/PhoP two-component system involved in responses to depletion of extracellular Mg2+. Here, we report the crystal structures of the receiver domain of Escherichia coli PhoP determined in the absence and presence of the phosphoryl analog beryllofluoride. In the presence of beryllofluoride, the active receiver domain forms a two-fold symmetric dimer similar to that seen in structures of other regulatory domains from the OmpR/PhoB family, providing further evidence that members of this family utilize a common mode of dimerization in the active state. In the absence of activating agents, the PhoP receiver domain crystallizes with a similar structure, consistent with the previous observation that high concentrations can promote an active state of PhoP independent of phosphorylation.