title: Structural basis for translation termination by archaeal RF1 and GTP-bound EF1α complex.
abstract: 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.
authors: Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan.
authors: Kan
authors: K
authors: Kobayashi
authors: Kazuki
authors: K
authors: Saito
authors: Ryuichiro
authors: R
authors: Ishitani
authors: Koichi
authors: K
authors: Ito
authors: Osamu
authors: O
authors: Nureki
mesh_terms: D019843:Archaeal Proteins / Q000737:chemistry* / Q000378:metabolism; D018388:Codon, Terminator; D006160:Guanosine Triphosphate / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D010443:Peptide Chain Termination, Translational; D020648:Peptide Elongation Factor 1 / Q000737:chemistry* / Q000378:metabolism; D010444:Peptide Elongation Factor Tu / Q000737:chemistry; D010454:Peptide Termination Factors / Q000737:chemistry* / Q000378:metabolism; D012343:RNA, Transfer / Q000737:chemistry; D040681:Structural Homology, Protein
chemical_list: D019843:Archaeal Proteins; D018388:Codon, Terminator; D020648:Peptide Elongation Factor 1; D010454:Peptide Termination Factors; D006160:Guanosine Triphosphate; D012343:RNA, Transfer; D010444:Peptide Elongation Factor Tu