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-Structure paper
タイトル | Visualization of two transfer RNAs trapped in transit during elongation factor G-mediated translocation. |
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ジャーナル・号・ページ | Proc Natl Acad Sci U S A, Vol. 110, Issue 52, Page 20964-20969, Year 2013 |
掲載日 | 2013年12月24日 |
著者 | David J F Ramrath / Laura Lancaster / Thiemo Sprink / Thorsten Mielke / Justus Loerke / Harry F Noller / Christian M T Spahn / |
PubMed 要旨 | During protein synthesis, coupled translocation of messenger RNAs (mRNA) and transfer RNAs (tRNA) through the ribosome takes place following formation of each peptide bond. The reaction is ...During protein synthesis, coupled translocation of messenger RNAs (mRNA) and transfer RNAs (tRNA) through the ribosome takes place following formation of each peptide bond. The reaction is facilitated by large-scale conformational changes within the ribosomal complex and catalyzed by elongtion factor G (EF-G). Previous structural analysis of the interaction of EF-G with the ribosome used either model complexes containing no tRNA or only a single tRNA, or complexes where EF-G was directly bound to ribosomes in the posttranslocational state. Here, we present a multiparticle cryo-EM reconstruction of a translocation intermediate containing two tRNAs trapped in transit, bound in chimeric intrasubunit ap/P and pe/E hybrid states. The downstream ap/P-tRNA is contacted by domain IV of EF-G and P-site elements within the 30S subunit body, whereas the upstream pe/E-tRNA maintains tight interactions with P-site elements of the swiveled 30S head. Remarkably, a tight compaction of the tRNA pair can be seen in this state. The translocational intermediate presented here represents a previously missing link in understanding the mechanism of translocation, revealing that the ribosome uses two distinct molecular ratchets, involving both intra- and intersubunit rotational movements, to drive the synchronous movement of tRNAs and mRNA. |
リンク | Proc Natl Acad Sci U S A / PubMed:24324168 / PubMed Central |
手法 | EM (単粒子) |
解像度 | 6.8 Å |
構造データ | |
化合物 | ChemComp-FUA: ChemComp-GDP: |
由来 |
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キーワード | RIBOSOME/TRANSLATION / translocation intermediate / EF-G / head swiveling / RIBOSOME-TRANSLATION complex |