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Enzyme
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Target Concepts:
Gene/Protein
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Query: EC:2.7.13.3 (
histidine kinase
)
2,405
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Histidine kinases function as dimers. The kinase domain of the osmosensing
histidine kinase
EnvZ
of Escherichia coli consists of two domains: domain A (67 residues) responsible for histidine phosphotransfer and dimerization, and domain B (161 residues) responsible for the catalytic and ATP-binding function. The individual structures of these two domains have been recently solved by NMR spectroscopy. Here, we demonstrate that an enzymatically functional monomeric
histidine kinase
can be constructed by fusing in tandem two domains A and one domain B to produce a single polypeptide (A-A-B). We show that this protein, EnvZc[
AAB
], is soluble and exists as a stable monomer. The autophosphorylation and OmpR kinase activities of the monomeric EnvZc[
AAB
] are similar to that of the wild-type
EnvZ
, while OmpR-binding and phosphatase functions are reduced. V8 protease digestion and mutational analyses indicate that His-243 of only the amino proximal domain A is phosphorylated. Based on these results, molecular models are proposed for the structures of EnvZc[
AAB
] and the kinase domain of
EnvZ
. The present results demonstrate for the first time the construction of a functional, monomeric
histidine kinase
, further structural studies of which may provide important insights into the structure-function relationships of histidine kinases.
...
PMID:A monomeric histidine kinase derived from EnvZ, an Escherichia coli osmosensor. 1076 Jan 60
