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

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  • Mickaël Blaise, Denmark
  • Marc Bailly
  • ,
  • Mathieu Frechin
  • ,
  • Manja Annette Behrens, Denmark
  • Frédéric Fischer
  • ,
  • Cristiano L P Oliveira, Denmark
  • Hubert Dominique Becker
  • ,
  • Jan Skov Pedersen
  • Søren Thirup
  • Daniel Kern
  • Department of Molecular Biology
  • iNano-School
  • Department of Chemistry
  • Interdisciplinary Nanoscience Center
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 Sep 2010

    Research areas

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

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