Document Detail


Crystal structure of a prokaryotic aspartyl tRNA-synthetase.
MedLine Citation:
PMID:  8045252     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The crystal structure of Thermus thermophilus aspartyl tRNA-synthetase (AspRS) refined at 2.5 A resolution is described. This molecular structure is a textbook illustration of the modular organization of aminoacyl-tRNA synthetases. In addition to the three domains found in yeast AspRS, each monomer exhibits a module specific to prokaryotic enzymes, which corresponds to a helix-turn-helix motif in yeast AspRS, a domain implicated in the stabilization of the complex with tRNA. Its topology matches that of the histidine-containing phosphocarrier HPr which has been linked recently to another group of proteins containing the ferredoxin fold. We propose a more extensive alignment of these folds, which involves a circular permutation of the sequences and changes the point of entry of the whole domain. The C-terminal extension, another prokaryotic characteristic, leads to a significant increase in the network of interaction at the dimer interface. Some potential communication pathways suggest how a transfer of information between the two active sites of the homodimer might occur. Most of the residues involved belong to the class II-specific motifs in correlation with the dimeric state of nearly all class II enzymes. The T. thermophilus enzyme exhibits some features not found in any of the six other known AspRSs from mesophilic organisms.
Authors:
M Delarue; A Poterszman; S Nikonov; M Garber; D Moras; J C Thierry
Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The EMBO journal     Volume:  13     ISSN:  0261-4189     ISO Abbreviation:  EMBO J.     Publication Date:  1994 Jul 
Date Detail:
Created Date:  1994-09-01     Completed Date:  1994-09-01     Revised Date:  2009-11-18    
Medline Journal Info:
Nlm Unique ID:  8208664     Medline TA:  EMBO J     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  3219-29     Citation Subset:  IM    
Affiliation:
Laboratoire de Biologie Structurale, IBMC du CNRS, Strasbourg, France.
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MeSH Terms
Descriptor/Qualifier:
Amino Acid Sequence
Aspartate-tRNA Ligase / chemistry*,  classification
Bacterial Proteins*
Binding Sites
Crystallography, X-Ray
Enzyme Stability
Eukaryotic Cells / enzymology
Ferredoxins / chemistry
Models, Molecular
Molecular Sequence Data
Phosphoenolpyruvate Sugar Phosphotransferase System / chemistry
Prokaryotic Cells / enzymology
Protein Conformation*
Sequence Homology, Amino Acid
Thermus thermophilus / enzymology*
Chemical
Reg. No./Substance:
0/Bacterial Proteins; 0/Ferredoxins; EC 2.7.1.-/Phosphoenolpyruvate Sugar Phosphotransferase System; EC 2.7.1.-/phosphocarrier protein HPr; EC 6.1.1.12/Aspartate-tRNA Ligase
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