The X-ray crystal structures of two constitutively active mutants of the Escherichia coli PhoB receiver domain give insights into activation.

ABSTRACT: The PhoR/PhoB two-component system is a key regulatory protein network enabling Escherichia coli to respond to inorganic phosphate (Pi) starvation conditions by turning on Pho regulon genes for more efficient Pi uptake and use of alternative phosphorus sources. Under environmental Pi depletion, the response regulator (RR) component, PhoB, is phosphorylated at the receiver domain (RD), a process that requires Mg(2+) bound at the active site. Phosphorylation of the RD relieves the inhibition of the PhoB effector domain (ED), a DNA-binding region that binds to Pho regulon promoters to activate transcription. The molecular details of the activation are proposed to involve dimerization of the RD and a conformational change in the RD detected by the ED. The structure of the PhoB RD shows a symme

SUBMITTER: Arribas-Bosacoma R 

PROVIDER: S-EPMC1855202 | biostudies-literature | 2007 Feb

REPOSITORIES: biostudies-literature