Action at a distance: amino acid substitutions that affect binding of the phosphorylated CheY response regulator and catalysis of dephosphorylation can be far from the CheZ phosphatase active site.

ABSTRACT: Two-component regulatory systems, in which phosphorylation controls the activity of a response regulator protein, provide signal transduction in bacteria. For example, the phosphorylated CheY response regulator (CheYp) controls swimming behavior. In Escherichia coli, the chemotaxis phosphatase CheZ stimulates the dephosphorylation of CheYp. CheYp apparently binds first to the C terminus of CheZ and then binds to the active site where dephosphorylation occurs. The phosphatase activity of the CheZ(2) dimer exhibits a positively cooperative dependence on CheYp concentration, apparently because the binding of the first CheYp to CheZ(2) is inhibited compared to the binding of the second CheYp. Thus, CheZ phosphatase activity is reduced at low CheYp concentrations. The CheZ21IT gain-of-function

SUBMITTER: Freeman AM 

PROVIDER: S-EPMC3165703 | biostudies-literature | 2011 Sep

REPOSITORIES: biostudies-literature