Linked Life Data

14979719

Source:http://linkedlifedata.com/resource/pubmed/id/14979719

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
8
pubmed:dateCreated
2004-2-24
pubmed:abstractText
Dimerization of the chemotaxis histidine kinase CheA is required for intersubunit autophosphorylation [Swanson, R. V., Bourret, R. B., and Simon, M. I. (1993) Mol. Microbiol. 8, 435-441]. Here we show that CheA dimers exchange subunits by the rate-limiting dissociation of a central four-helix bundle association domain (P3), despite the high stability of P3 versus unfolding. P3 alone determines the stability and exchange properties of the CheA dimer. For CheA proteins from the mesophile Escherichia coli and the thermophile Thermotoga maritima, subunit dissociation activates at temperatures where the respective organisms live (37 and 80 degrees C). Under destabilizing conditions, P3 dimer dissociation is cooperative with unfolding. Chemical denaturation is reversible for both EP3 and TP3. Aggregation accompanies thermal unfolding for both proteins under most conditions, but thermal unfolding is reversible and two-state for EP3 at low protein concentrations. Residue differences within interhelical loops may account for the contrasted thermodynamic properties of structurally similar EP3 and TP3 (41% sequence identity). Under stabilizing conditions, greater correlation between activation energy for dimer dissociation and P3 stability suggests more unfolding in the dissociation of EP3 than TP3. Furthermore, destabilization of extended conformations by glycerol slows relative dissociation rates more for EP3 than for TP3. Nevertheless, at physiological temperatures, neither protein likely unfolds completely during subunit exchange. EP3 and TP3 will not exchange subunits with each other. The receptor coupling protein CheW reduces the subunit dissociation rate of the T. maritima CheA dimer by interacting with the regulatory domain P5.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
2
pubmed:volume
43
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2228-40
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed-meshheading:14979719-Amino Acid Sequence, pubmed-meshheading:14979719-Bacterial Proteins, pubmed-meshheading:14979719-Chemotaxis, pubmed-meshheading:14979719-Dimerization, pubmed-meshheading:14979719-Enzyme Stability, pubmed-meshheading:14979719-Escherichia coli, pubmed-meshheading:14979719-Escherichia coli Proteins, pubmed-meshheading:14979719-Kinetics, pubmed-meshheading:14979719-Membrane Proteins, pubmed-meshheading:14979719-Models, Chemical, pubmed-meshheading:14979719-Molecular Sequence Data, pubmed-meshheading:14979719-Protein Folding, pubmed-meshheading:14979719-Protein Kinase Inhibitors, pubmed-meshheading:14979719-Protein Kinases, pubmed-meshheading:14979719-Protein Subunits, pubmed-meshheading:14979719-Structural Homology, Protein, pubmed-meshheading:14979719-Temperature, pubmed-meshheading:14979719-Thermodynamics, pubmed-meshheading:14979719-Thermotoga maritima
pubmed:year
2004
pubmed:articleTitle
Subunit exchange by CheA histidine kinases from the mesophile Escherichia coli and the thermophile Thermotoga maritima.
pubmed:affiliation
Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, U.S. Gov't, P.H.S.