Linked Life Data

4084496

Source:http://linkedlifedata.com/resource/pubmed/id/4084496

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
21
pubmed:dateCreated
1986-2-28
pubmed:abstractText
Dimeric tyrosyl-tRNA synthetase from Bacillus stearothermophilus exhibits half-of-the-sites reactivity and negative cooperativity in binding of tyrosine. Protein engineering has been applied to the enzyme to determine whether it can be reversibly dissociated into monomers and if the monomers are active. The target for mutation is the residue Phe-164. The side chain of Phe-164 in one subunit interacts with its symmetry-related partner in the other. Mutation of Phe-164----Asp-164 gives a mutant [TyrTS(Asp-164)] that undergoes dissociation at high pH when the aspartate residues are ionized. The monomer is inactive and does not bind tyrosine. Dissociation is enhanced at low concentrations of enzyme by a mass action effect. Kinetic and binding measurements on TyrTS(Asp-164) with tyrosine and tyrosyl adenylate show that the monomer has very weak affinity for these ligands. Accordingly, dimerization is favored by high concentrations of tyrosine and ATP since the dimeric form has a high affinity for the ligands. The presence of tRNA does not encourage dimer formation, and so it must bind to the monomer. TyrTS(Asp-164) is fully active at pH 6 where dimerization is favored but has low activity at pH 7.8 where dissociation is favored. It should now prove possible to engineer heterodimers that may be used to investigate the subunit interactions further.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
8
pubmed:volume
24
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
5852-7
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
1985
pubmed:articleTitle
Reversible dissociation of dimeric tyrosyl-tRNA synthetase by mutagenesis at the subunit interface.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't