Linked Life Data

10350484

Source:http://linkedlifedata.com/resource/pubmed/id/10350484

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
20
pubmed:dateCreated
1999-6-9
pubmed:abstractText
The chemotaxis receptor for aspartate, Tar, generates responses by regulating the activity of an associated histidine kinase, CheA. Tar is composed of an extracellular sensory domain connected by a transmembrane sequence to a cytoplasmic signaling domain. The cytoplasmic domain fused to a leucine zipper dimerization domain forms soluble active ternary complexes with CheA and an adapter protein, CheW. The kinetics of kinase activity within these complexes compared to CheA alone indicate approximately a 50% decrease in the KM for ATP and a 100-fold increase in the Vmax. A truncated CheA construct that lacks the phosphoaccepting H-domain and the CheY/CheB-binding domain forms an activated ternary complex that is similar to the one formed by the full-length CheA protein. The Vmax of H-domain phosphorylation by this complex is enhanced approximately 60-fold, the KM for ATP decreased to 50%, and the KM for H-domain decreased to 20% of the values obtained with the same CheA construct in the absence of receptor and CheW. The kinetic data support a mechanism of CheA regulation that involves perturbation of an equilibrium between an inactive form where the H-domain is loosely bound and an active form where the H-domain is tightly associated with the CheA active site and properly positioned for phosphotransfer. The data are consistent with an asymmetric mechanism of CheA activation [Levit, M., Liu, I., Surette, M. G., and Stock, J. B. (1996) J. Biol. Chem. 271, 32057-32063] wherein only one phosphoaccepting domain of CheA at a time can interact with an active center within a CheA dimer.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
http://linkedlifedata.com/resource/pubmed/chemical/Bacterial Proteins, http://linkedlifedata.com/resource/pubmed/chemical/CheW protein, Bacteria, http://linkedlifedata.com/resource/pubmed/chemical/CheW protein, E coli, http://linkedlifedata.com/resource/pubmed/chemical/Escherichia coli Proteins, http://linkedlifedata.com/resource/pubmed/chemical/Macromolecular Substances, http://linkedlifedata.com/resource/pubmed/chemical/Membrane Proteins, http://linkedlifedata.com/resource/pubmed/chemical/Protein Kinases, http://linkedlifedata.com/resource/pubmed/chemical/Receptors, Cell Surface, http://linkedlifedata.com/resource/pubmed/chemical/Tar protein, E coli, http://linkedlifedata.com/resource/pubmed/chemical/methyl-accepting chemotaxis proteins, http://linkedlifedata.com/resource/pubmed/chemical/protein-histidine kinase
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
18
pubmed:volume
38
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
6651-8
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
1999
pubmed:articleTitle
Mechanism of CheA protein kinase activation in receptor signaling complexes.
pubmed:affiliation
Department of Molecular Biology, Princeton University, New Jersey 08544, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.