3bq8

Structural highlights

Function

PHOQ_ECOLI Member of the two-component regulatory system PhoP/PhoQ involved in adaptation to low Mg(2+) environments and the control of acid resistance genes. In low periplasmic Mg(2+), PhoQ functions as a membrane-associated protein kinase that undergoes autophosphorylation and subsequently transfers the phosphate to PhoP, resulting in the expression of PhoP-activated genes (PAG) and repression of PhoP-repressed genes (PRG). In high periplasmic Mg(2+), acts as a protein phosphatase that dephosphorylates phospho-PhoP, resulting in the repression of PAG and may lead to expression of some PRG (By similarity). PhoP-regulated transcription is redox-sensitive, being activated when the periplasm becomes more reducing (deletion of dsbA/dsbB, or treatment with dithiothreitol). MgrB acts between DsbA/DsbB and PhoP/PhoQ in this pathway; the 2 periplasmic Cys residues of MgrB are required for its action on PhoQ, which then acts on PhoP. Mediates magnesium influx to the cytosol by activation of mgtA. Promotes expression of the two-component regulatory system rstA/rstB and transcription of the hemL, mgrB, nagA, slyB, vboR and yrbL genes.^[1]

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

See Also

• PhoP-PhoQ

References

1. ↑ Kato A, Tanabe H, Utsumi R. Molecular characterization of the PhoP-PhoQ two-component system in Escherichia coli K-12: identification of extracellular Mg2+-responsive promoters. J Bacteriol. 1999 Sep;181(17):5516-20. PMID:10464230
2. ↑ Cheung J, Bingman CA, Reyngold M, Hendrickson WA, Waldburger CD. Crystal structure of a functional dimer of the PhoQ sensor domain. J Biol Chem. 2008 May 16;283(20):13762-70. Epub 2008 Mar 18. PMID:18348979 doi:10.1074/jbc.M710592200