Premium
Intermolecular complementation of the kinase activity of CheA
Author(s) -
Swanson Ronald V.,
Bourret Robert B.,
Simon Melvjn I.
Publication year - 1993
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.1993.tb01588.x
Subject(s) - autophosphorylation , histidine kinase , biology , phosphorylation , chemotaxis , mutant , microbiology and biotechnology , signal transduction , kinase , biochemistry , protein kinase domain , protein kinase a , gene , receptor
Summary CheA is a dimeric autophosphorylating protein kinase that plays a critical role in the signal transduction network controlling chemotaxis In Escherichia coli . The autophosphorylation reaction was analysed using mutant proteins defective in kinase and regulatory functions. Proteins in which the site of autophosphorylation was mutated (CheA48HQ) or missing (CheA s ) were found to phosphorylate the kinase‐defective mutant, CheA470GK. The kinetics of this reaction support the hypothesis that autophosphorylation is the result of trans‐phosphorylation within a dimer. The carboxy‐terminal portion of CheA was previously shown to be dispensable for autophosphorylation, but required for regulation in response to environmental signals transmitted through a transducer and CheW. Mixing of CheA48HQ or CheA470GK with a truncated protein lacking this regulatory domain demonstrated that regulated autophosphoryltion requires the presence of both carboxy‐terminal portions in a CheA dimer. These results indicate that the dimeric form of CheA plays an integral role in signal transduction in bacterial chemotaxis.