Linked Life Data

2890374

Source:http://linkedlifedata.com/resource/pubmed/id/2890374

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
17
pubmed:dateCreated
1987-12-28
pubmed:abstractText
In order to evaluate a possible contribution of glutamate-190, situated in the hinge region of yeast 3-phosphoglycerate kinase (PGK), to the mechanism of the substrate- and sulfate-induced domain movement, we have constructed two point mutants, Gln-190 and Asp-190, using oligonucleotide-directed in vitro mutagenesis. The Michaelis constants of the mutants for ATP and 3-phosphoglycerate were not significantly altered, whereas the catalytic activities were decreased, both in the absence and in the presence of sulfate ions. In the absence of sulfate, the Gln-190 and Asp-190 mutants exhibited 26% and 36% of the activity of the native enzyme. In the presence of 30 mM Na2SO4, a concentration at which native PGK exhibits maximum activation, the relative activities of the Gln-190 and Asp-190 mutants were 6% and 9%, respectively. In contrast to the native enzyme, which undergoes activation at low sulfate concentrations and inhibition at high concentrations, both mutants showed a complete loss of the salt activation effect. These results suggest that Glu-190 is not directly involved in the binding of substrates but might be important for conformational flexibility. We have also demonstrated that, similarly to native PGK, both mutants are completely inactivated by the incorporation of 1 mol of glycine ethyl ester/mol of enzyme. Appreciable protection against inactivation is observed in the presence of both substrates, MgATP and 3-phosphoglycerate. Only limited protection is observed in the presence of the individual substrates, suggesting that the modification does not occur at the substrate binding sites.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
25
pubmed:volume
26
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
5369-77
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1987
pubmed:articleTitle
Site-directed mutagenesis of glutamate-190 in the hinge region of yeast 3-phosphoglycerate kinase: implications for the mechanism of domain movement.
pubmed:affiliation
Division of Biology, Beckman Research Institute of the City of Hope, Duarte, California 91010.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't