Linked Life Data

7776367

Source:http://linkedlifedata.com/resource/pubmed/id/7776367

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1995-7-11
pubmed:abstractText
Hsp70 chaperons interact with protein substrates in an ATP-dependent manner to prevent aggregation and promote protein folding. For the Escherichia coli homolog DnaK, we have characterized the ATP hydrolysis cycle as well as the effects of the DnaJ and GrpE cofactors on substrate interaction to reach conclusions on the functional cycle. DnaK ATPase was stimulated by substrates (ninefold) and DnaJ (13-fold) through stimulation of the rate limiting step, gamma-phosphate cleavage (approximately tenfold slower than ADP release). Substrates stimulate ATPase after binding with high affinity (KA < 10 microM) to preformed DnaK-ATP complexes. The rapid binding kinetics lead to the conclusion that ATP-bound DnaK is the primary form initiating interaction with substrates for chaperone activity. The resulting DnaK-ATP-substrate complexes, however, are also characterized by rapid dissociation of bound substrate, but can be stabilized by hydrolysis of ATP (stimulated either by the substrate itself or DnaJ through their effects on the rate-limiting step). Stimulation of the gamma-phosphate cleavage reaction by DnaJ is much more efficient (complete conversion of bound ATP to ADP within five seconds) than that by substrates, indicating the special and important role for DnaJ in stabilization of DnaK-substrate interactions.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0022-2836
pubmed:author
pubmed:issnType
Print
pubmed:day
26
pubmed:volume
249
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
126-37
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
The role of ATP in the functional cycle of the DnaK chaperone system.
pubmed:affiliation
Zentrum für Molekulare Biologie, Universität Heidelberg, FRG.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't