Document Detail


Post-transfer editing in vitro and in vivo by the beta subunit of phenylalanyl-tRNA synthetase.
MedLine Citation:
PMID:  15526031     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Translation of the genetic code requires attachment of tRNAs to their cognate amino acids. Errors during amino-acid activation and tRNA esterification are corrected by aminoacyl-tRNA synthetase-catalyzed editing reactions, as extensively described for aliphatic amino acids. The contribution of editing to aromatic amino-acid discrimination is less well understood. We show that phenylalanyl-tRNA synthetase misactivates tyrosine and that it subsequently corrects such errors through hydrolysis of tyrosyl-adenylate and Tyr-tRNA(Phe). Structural modeling combined with an in vivo genetic screen identified the editing site in the B3/B4 domain of the beta subunit, 40 angstroms from the active site in the alpha subunit. Replacements of residues within the editing site had no effect on Phe-tRNA(Phe) synthesis, but abolished hydrolysis of Tyr-tRNA(Phe) in vitro. Expression of the corresponding mutants in Escherichia coli significantly slowed growth, and changed the activity of a recoded beta-galactosidase variant by misincorporating tyrosine in place of phenylalanine. This loss in aromatic amino-acid discrimination in vivo revealed that editing by phenylalanyl-tRNA synthetase is essential for faithful translation of the genetic code.
Authors:
Hervé Roy; Jiqiang Ling; Michael Irnov; Michael Ibba
Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.     Date:  2004-11-04
Journal Detail:
Title:  The EMBO journal     Volume:  23     ISSN:  0261-4189     ISO Abbreviation:  EMBO J.     Publication Date:  2004 Nov 
Date Detail:
Created Date:  2004-11-24     Completed Date:  2005-06-28     Revised Date:  2013-04-18    
Medline Journal Info:
Nlm Unique ID:  8208664     Medline TA:  EMBO J     Country:  England    
Other Details:
Languages:  eng     Pagination:  4639-48     Citation Subset:  IM    
Affiliation:
Department of Microbiology, The Ohio State University, Columbus, OH 43210-1292, USA.
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MeSH Terms
Descriptor/Qualifier:
Escherichia coli / enzymology*,  genetics
Hydrolysis
Models, Molecular
Mutation
Phenylalanine / metabolism
Phenylalanine-tRNA Ligase / genetics,  metabolism*
Plasmids
Protein Biosynthesis*
Protein Subunits / genetics,  metabolism
RNA, Transfer, Phe / genetics,  metabolism
Tyrosine / metabolism
Tyrosine-tRNA Ligase / genetics,  metabolism
Chemical
Reg. No./Substance:
0/Protein Subunits; 0/RNA, Transfer, Phe; 55520-40-6/Tyrosine; 63-91-2/Phenylalanine; EC 6.1.1.1/Tyrosine-tRNA Ligase; EC 6.1.1.20/Phenylalanine-tRNA Ligase
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