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

Mickaël Blaise, Marc Bailly, Mathieu Frechin, Manja Annette Behrens, Frédéric Fischer, Cristiano L P Oliveira, Hubert Dominique Becker, Jan Skov Pedersen, Søren Thirup, Daniel Kern

    Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaperJournal articleResearchpeer-review

    Abstract

    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.
    Original languageEnglish
    JournalThe EMBO Journal
    Volume29
    Issue18
    Pages (from-to)3118-29
    Number of pages12
    DOIs
    Publication statusPublished - 15 Sept 2010

    Keywords

    • Asparagine
    • Crystallization
    • Nitrogenous Group Transferases
    • Protein Conformation
    • RNA, Transfer, Asn
    • Ribonucleoproteins
    • Thermus thermophilus
    • Transfer RNA Aminoacylation

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