The transamidosome: a dynamic ribonucleoprotein particle dedicated to prokaryotic tRNA-dependent asparagine biosynthesis. - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Molecular Cell Année : 2007

The transamidosome: a dynamic ribonucleoprotein particle dedicated to prokaryotic tRNA-dependent asparagine biosynthesis.

Résumé

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.

Dates et versions

hal-00199217 , version 1 (18-12-2007)

Identifiants

Citer

Marc Bailly, Mickaël Blaise, Bernard Lorber, Hubert Dominique Becker, Daniel Kern. The transamidosome: a dynamic ribonucleoprotein particle dedicated to prokaryotic tRNA-dependent asparagine biosynthesis.. Molecular Cell, 2007, 28 (2), pp.228-39. ⟨10.1016/j.molcel.2007.08.017⟩. ⟨hal-00199217⟩

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