The transamidosome: a dynamic ribonucleoprotein particle dedicated to prokaryotic tRNA-dependent asparagine biosynthesis.
Mol Cell
; 28(2): 228-39, 2007 Oct 26.
Article
en En
| MEDLINE
| ID: mdl-17964262
ABSTRACT
Asparagine, one of the 22 genetically encoded amino acids, can be synthesized by a tRNA-dependent mechanism. So far, this type of pathway was believed to proceed via two independent steps. A nondiscriminating aspartyl-tRNA synthetase (ND-DRS) first generates a mischarged aspartyl-tRNAAsn that dissociates from the enzyme and binds to a tRNA-dependent amidotransferase (AdT), which then converts the tRNA-bound aspartate into asparagine. We show herein that the ND-DRS, tRNAAsn, and AdT assemble into a specific ribonucleoprotein complex called transamidosome that remains stable during the overall catalytic process. Our results indicate that the tRNAAsn-mediated linkage between the ND-DRS and AdT enables channeling of the mischarged aspartyl-tRNAAsn intermediate between DRS and AdT active sites to prevent challenging of the genetic code integrity. We propose that formation of a ribonucleoprotein is a general feature for tRNA-dependent amino acid biosynthetic pathways that are remnants of earlier stages when amino acid synthesis and tRNA aminoacylation were coupled.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Asparagina
/
Aspartato-ARNt Ligasa
/
Ribonucleoproteínas
/
Biosíntesis de Proteínas
/
ARN de Transferencia de Asparagina
/
Aminoacil-ARN de Transferencia
/
Thermus thermophilus
/
Transferasas de Grupos Nitrogenados
Idioma:
En
Revista:
Mol Cell
Asunto de la revista:
BIOLOGIA MOLECULAR
Año:
2007
Tipo del documento:
Article
País de afiliación:
Francia