| Aminoacyl-tRNA synthesis by pre-translational amino acid modification. | |
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MedLine Citation:
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PMID: 17194933 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Aminoacyl-tRNAs (aa-tRNAs) are essential substrates for ribosomal translation, and are generally synthesized by aminoacyl-tRNA synthetases (aaRSs). It was expected earlier that every organism would contain a complete set of twenty aaRSs, one for each canonical amino acid. However, analysis of the many known genome sequences and biochemical studies revealed that most organisms lack asparaginyl- and glutaminyl-tRNA synthetases, and thus are unable to attach asparagine and glutamine directly onto their corresponding tRNA. Instead, a pretranslational amino acid modification is required to convert Asp-tRNA(Asn) and Glu-tRNA(Gln) to the correctly charged Asn-tRNA(Asn) and Gln-tRNA(Gln), respectively. This transamidation pathway of amide aa-tRNA synthesis is common in most bacteria and archaea. Unexpected results from biochemical, genetic and genomic studies showed that a large variety of different bacteria rely on tRNA-dependent transamidation for the formation of the amino acid asparagine. Pretranslational modifications are not restricted to asparagine and glutamine but are also found in the biosynthesis of some other aa-tRNAs, such as the initiator tRNA fmet-tRNA(Met)(i) and Sec-tRNA(Sec) specifying selenocysteine, the 21(st) cotranslationally inserted amino acid. tRNA-dependent amino acid modification is also involved in the generation of aminolevulinic acid, the first precursor for porphyrin biosynthesis in many organisms. |
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Authors:
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Liang Feng; Kelly Sheppard; Suk Namgoong; Alexandre Ambrogelly; Carla Polycarpo; Lennart Randau; Debra Tumbula-Hansen; Dieter Söll |
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Publication Detail:
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Type: Journal Article; Research Support, N.I.H., Extramural; Research Support, U.S. Gov't, Non-P.H.S.; Review Date: 2004-05-28 |
Journal Detail:
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Title: RNA biology Volume: 1 ISSN: 1555-8584 ISO Abbreviation: RNA Biol Publication Date: 2004 May |
Date Detail:
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Created Date: 2006-12-29 Completed Date: 2007-02-12 Revised Date: 2010-01-15 |
Medline Journal Info:
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Nlm Unique ID: 101235328 Medline TA: RNA Biol Country: United States |
Other Details:
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Languages: eng Pagination: 16-20 Citation Subset: IM |
Affiliation:
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Department of Molecular Biophysics, Yale University, New Haven, Connecticut 06520-8114, USA. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Amino Acids
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chemistry Amino Acyl-tRNA Synthetases / chemistry, physiology* Archaea / metabolism Asparagine / chemistry Bacillus subtilis / metabolism Chlorophyll / chemistry Escherichia coli / metabolism Glutamine / chemistry Heme / chemistry Models, Biological Phylogeny Porphyrins / chemistry Protein Modification, Translational* RNA, Transfer, Amino Acyl* Species Specificity |
| Chemical | |
Reg. No./Substance:
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0/Amino Acids; 0/Porphyrins; 0/RNA, Transfer, Amino Acyl; 1406-65-1/Chlorophyll; 14875-96-8/Heme; 56-85-9/Glutamine; 7006-34-0/Asparagine; EC 6.1.1.-/Amino Acyl-tRNA Synthetases |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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