Crystal structure of a transfer-ribonucleoprotein particle that promotes asparagine formation. - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue EMBO Journal Année : 2010

Crystal structure of a transfer-ribonucleoprotein particle that promotes asparagine formation.

Résumé

Four out of the 22 aminoacyl-tRNAs (aa-tRNAs) are systematically or alternatively synthesized by an indirect, two-step route requiring an initial mischarging of the tRNA followed by tRNA-dependent conversion of the non-cognate amino acid. During tRNA-dependent asparagine formation, tRNA(Asn) promotes assembly of a ribonucleoprotein particle called transamidosome that allows channelling of the aa-tRNA from non-discriminating aspartyl-tRNA synthetase active site to the GatCAB amidotransferase site. The crystal structure of the Thermus thermophilus transamidosome determined at 3 A resolution reveals a particle formed by two GatCABs, two dimeric ND-AspRSs and four tRNAs(Asn) molecules. In the complex, only two tRNAs are bound in a functional state, whereas the two other ones act as an RNA scaffold enabling release of the asparaginyl-tRNA(Asn) without dissociation of the complex. We propose that the crystal structure represents a transient state of the transamidation reaction. The transamidosome constitutes a transfer-ribonucleoprotein particle in which tRNAs serve the function of both substrate and structural foundation for a large molecular machine.

Dates et versions

hal-00526386 , version 1 (14-10-2010)

Identifiants

Citer

Mickaël Blaise, Marc Bailly, Mathieu Frechin, Manja Annette Behrens, Frédéric Fischer, et al.. Crystal structure of a transfer-ribonucleoprotein particle that promotes asparagine formation.. EMBO Journal, 2010, 29 (18), pp.3118-29. ⟨10.1038/emboj.2010.192⟩. ⟨hal-00526386⟩

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