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rdf:type |
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lifeskim:mentions |
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pubmed:issue |
23
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pubmed:dateCreated |
1986-1-6
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pubmed:abstractText |
The principal catalytic factor in the activation of tyrosine by the tyrosyl-tRNA synthetase is found to be improved binding of ATP in the transition state. The activation reaction involves the attack of the tyrosyl carboxylate on the alpha-phosphate group of ATP to generate a pentacoordinate transition state. Model building of this complex located a binding site for the gamma-phosphate group of ATP, consisting of hydrogen bonds with the side chains of Thr-40 and His-45. Removal of these groups by protein engineering shows that they contribute no binding energy with unreacted ATP but put all of their binding energy into stabilizing the [tyrosine-ATP] transition state [the mutant tyrosyl-tRNA synthetase (Thr-40----Ala-40; His-45----Gly-45) has the rate of formation of tyrosyl adenylate lowered by 3.2 X 10(5) but KS for ATP is lowered by only a factor of 5]. The side chains of these residues also provide a binding site for pyrophosphate in the reverse reaction. Thus, catalysis is accomplished by stabilization of the transition state by improved binding of a group on the substrate that is distant from the seat of reaction.
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pubmed:commentsCorrections |
http://linkedlifedata.com/resource/pubmed/commentcorrection/3865201-1096942,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3865201-162826,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3865201-3845322,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3865201-4074680,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3865201-4155501,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3865201-5288752,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3865201-6315404,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3865201-6323720,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3865201-6488318,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3865201-6615786,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3865201-6751870,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3865201-6811955,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3865201-892
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pubmed:language |
eng
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pubmed:journal |
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pubmed:citationSubset |
IM
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pubmed:chemical |
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pubmed:status |
MEDLINE
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pubmed:month |
Dec
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pubmed:issn |
0027-8424
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pubmed:author |
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pubmed:issnType |
Print
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pubmed:volume |
82
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
7840-4
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pubmed:dateRevised |
2009-11-19
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pubmed:meshHeading |
pubmed-meshheading:3865201-Adenosine Triphosphate,
pubmed-meshheading:3865201-Amino Acid Sequence,
pubmed-meshheading:3865201-Amino Acyl-tRNA Synthetases,
pubmed-meshheading:3865201-Binding Sites,
pubmed-meshheading:3865201-Genetic Engineering,
pubmed-meshheading:3865201-Geobacillus stearothermophilus,
pubmed-meshheading:3865201-Kinetics,
pubmed-meshheading:3865201-Magnesium,
pubmed-meshheading:3865201-Mutation,
pubmed-meshheading:3865201-Structure-Activity Relationship,
pubmed-meshheading:3865201-Thermodynamics,
pubmed-meshheading:3865201-Tyrosine,
pubmed-meshheading:3865201-Tyrosine-tRNA Ligase
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pubmed:year |
1985
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pubmed:articleTitle |
Transition-state stabilization in the mechanism of tyrosyl-tRNA synthetase revealed by protein engineering.
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pubmed:publicationType |
Journal Article
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