Linked Life Data

8917315

Source:http://linkedlifedata.com/resource/pubmed/id/8917315

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
1996-12-9
pubmed:abstractText
It has previously been shown that the single mutation E222K in glutaminyl-tRNA synthetase (GlnRS) confers a temperature-sensitive phenotype on Escherichia coli. Here we report the isolation of a pseudorevertant of this mutation, E222K/C171G, which was subsequently employed to investigate the role of these residues in substrate discrimination. The three-dimensional structure of the tRNA(Gln): GlnRS: ATP ternary complex revealed that both E222 and C171 are close to regions of the protein involved in interactions with both the acceptor stem and the 3' end of tRNA(Gln). The potential involvement of E222 and C171 in these interactions was confirmed by the observation that GlnRS-E222K was able to mischarge supF tRNA(Tyr) considerably more efficiently than the wild-type enzyme, whereas GlnRS-E222K/C171G could not. These differences in substrate specificity also extended to anticodon recognition, with the double mutant able to distinguish supE tRNA(CUA)(Gln) from tRNA2(Gln) considerably more efficiently than GlnRS E222K. Furthermore, GlnRS-E222K was found to have a 15-fold higher K(m) for glutamine than the wild-type enzyme, whereas the double mutant only showed a 7-fold increase. These results indicate that the C171G mutation improves both substrate discrimination and recognition at three domains in GlnRS-E222K, confirming recent proposals that there are extensive interactions between the active site and regions of the enzyme involved in tRNA binding.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0026-8925
pubmed:author
pubmed:issnType
Print
pubmed:day
28
pubmed:volume
252
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
717-22
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1996
pubmed:articleTitle
Genetic analysis of functional connectivity between substrate recognition domains of Escherichia coli glutaminyl-tRNA synthetase.
pubmed:affiliation
Department of Biophysics, Faculty of Science, Kyoto University, Japan.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't