Linked Life Data

8955904

Source:http://linkedlifedata.com/resource/pubmed/id/8955904

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
7
pubmed:dateCreated
1997-3-11
pubmed:abstractText
Structure/function relationships accounting for specific tRNA charging by class II aspartyl-tRNA synthetases from Saccharomyces cerevisiae, Escherichia coli and Thermus thermophilus are reviewed. Effects directly linked to tRNA features are emphasized and aspects about synthetase contribution in expression of tRNA(Asp) identity are also covered. Major identity nucleotides conferring aspartate specificity to yeast, E coli and T thermophilus tRNAs comprise G34, U35, C36, C38 and G73, a set of nucleotides conserved in tRNA(Asp) molecules of other biological origin. Aspartate specificity can be enhanced by negative discrimination preventing, eg mischarging of native yeast tRNA(Asp by yeast arginyl-tRNA synthetase. In the yeast system crystallography shows that identity nucleotides are in contact with identity amino acids located in the catalytic and anticodon binding domains of the synthetase. Specificity of RNA/protein interaction involves a conformational change of the tRNA that optimizes the H-bonding potential of the identity signals on both partners of the complex. Mutation of identity nucleotides leads to decreased aspartylation efficiencies accompanied by a loss of specific H-bonds and an altered adaptation of tRNA on the synthetase. Species-specific characteristics of aspartate systems are the number, location and nature of minor identity signals. These features and the structural variations in aspartate tRNAs and synthetases are correlated with mechanistic differences in the aminoacylation reactions catalyzed by the various aspartyl-tRNA synthetases. The reality of the aspartate identity set is verified by its functional expression in a variety of RNA frameworks. Inversely a number of identities can be expressed within a tRNA(Asp) framework. From this emerged the concept of the RNA structural frameworks underlying expression of identities which is illustrated with data obtained with engineered tRNAs. Efficient aspartylation of minihelices is explained by the primordial role of G73. From this and other considerations it is suggested that aspartate identity appeared early in the history of tRNA aminoacylation systems.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0300-9084
pubmed:author
pubmed:issnType
Print
pubmed:volume
78
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
605-23
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1996
pubmed:articleTitle
Aspartate identity of transfer RNAs.
pubmed:affiliation
Unité Structure des Macromolécules Biologioues et Mécanismes de Reconnaissance, Institut de Biologie Moléculaire et Cellulaire du CNRS, Strasbourg, France.
pubmed:publicationType
Journal Article, Review, Research Support, Non-U.S. Gov't