Linked Life Data

1351296

Source:http://linkedlifedata.com/resource/pubmed/id/1351296

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1276
pubmed:dateCreated
1992-7-10
pubmed:abstractText
Guanine nucleotides modified by acetylation of the ribose moiety with the small fluorophore N-methylanthranilic acid(mant) have been shown to bind to p21 ras with similar equilibrium and kinetic rate constants as the parent nucleotides. Hydrolysis of p21.mantGTP to p21.mantGDP results in a 10% decrease in fluorescence intensity occurring at the same rate as the cleavage step. A similar process occurs with the non-hydrolysable analogue mantGMP.PNP, and this has led to the proposal that a conformational change of p21.mantGTP precedes and controls the rate of the cleavage step. The fluorescence change with p21.mantGMP.PNP is accelerated in the presence of the C-terminal catalytic domain of GAP, which is consistent with this mechanism. The same conformational change does not occur with oncogenic mutants of p21 ras, Asp-12 and Val-12, but does occur with the weakly oncogenic Pro-12 mutant. Stopped flow measurements of the interaction of GAP with p21.mantGTP show an exponential decrease in fluorescence, the rate of which does not vary linearly with GAP concentration. These data imply a rapidly reversible formation of the p21.mantGTP complex with GAP followed by the isomerization of this complex. This is at least 10(5)-fold faster than the same process in the absence of GAP.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0962-8436
pubmed:author
pubmed:issnType
Print
pubmed:day
29
pubmed:volume
336
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
49-53; discussion 53-4
pubmed:dateRevised
2005-11-17
pubmed:meshHeading
pubmed:year
1992
pubmed:articleTitle
The kinetic mechanism of the GAP-activated GTPase of p21 ras.
pubmed:affiliation
National Institute for Medical Research, London, U.K.
pubmed:publicationType
Journal Article, Review