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Structural basis for translation termination by archaeal RF1 and GTP-bound EF1α complex

When a stop codon appears at the ribosomal A site, the class I and II release factors (RFs) terminate translation. In eukaryotes and archaea, the class I and II RFs form a heterodimeric complex, and complete the overall translation termination process in a GTP-dependent manner. However, the structur...

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Detalles Bibliográficos
Autores principales: Kobayashi, Kan, Saito, Kazuki, Ishitani, Ryuichiro, Ito, Koichi, Nureki, Osamu
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Oxford University Press 2012
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3467058/
https://www.ncbi.nlm.nih.gov/pubmed/22772989
http://dx.doi.org/10.1093/nar/gks660
Descripción
Sumario:When a stop codon appears at the ribosomal A site, the class I and II release factors (RFs) terminate translation. In eukaryotes and archaea, the class I and II RFs form a heterodimeric complex, and complete the overall translation termination process in a GTP-dependent manner. However, the structural mechanism of the translation termination by the class I and II RF complex remains unresolved. In archaea, archaeal elongation factor 1 alpha (aEF1α), a carrier GTPase for tRNA, acts as a class II RF by forming a heterodimeric complex with archaeal RF1 (aRF1). We report the crystal structure of the aRF1·aEF1α complex, the first active class I and II RF complex. This structure remarkably resembles the tRNA·EF–Tu complex, suggesting that aRF1 is efficiently delivered to the ribosomal A site, by mimicking tRNA. It provides insights into the mechanism that couples GTP hydrolysis by the class II RF to stop codon recognition and peptidyl-tRNA hydrolysis by the class I RF. We discuss the different mechanisms by which aEF1α recognizes aRF1 and aPelota, another aRF1-related protein and molecular evolution of the three functions of aEF1α.