+検索条件
-Structure paper
タイトル | Head swivel on the ribosome facilitates translocation by means of intra-subunit tRNA hybrid sites. |
---|---|
ジャーナル・号・ページ | Nature, Vol. 468, Issue 7324, Page 713-716, Year 2010 |
掲載日 | 2010年12月2日 |
著者 | Andreas H Ratje / Justus Loerke / Aleksandra Mikolajka / Matthias Brünner / Peter W Hildebrand / Agata L Starosta / Alexandra Dönhöfer / Sean R Connell / Paola Fucini / Thorsten Mielke / Paul C Whitford / José N Onuchic / Yanan Yu / Karissa Y Sanbonmatsu / Roland K Hartmann / Pawel A Penczek / Daniel N Wilson / Christian M T Spahn / |
PubMed 要旨 | The elongation cycle of protein synthesis involves the delivery of aminoacyl-transfer RNAs to the aminoacyl-tRNA-binding site (A site) of the ribosome, followed by peptide-bond formation and ...The elongation cycle of protein synthesis involves the delivery of aminoacyl-transfer RNAs to the aminoacyl-tRNA-binding site (A site) of the ribosome, followed by peptide-bond formation and translocation of the tRNAs through the ribosome to reopen the A site. The translocation reaction is catalysed by elongation factor G (EF-G) in a GTP-dependent manner. Despite the availability of structures of various EF-G-ribosome complexes, the precise mechanism by which tRNAs move through the ribosome still remains unclear. Here we use multiparticle cryoelectron microscopy analysis to resolve two previously unseen subpopulations within Thermus thermophilus EF-G-ribosome complexes at subnanometre resolution, one of them with a partly translocated tRNA. Comparison of these substates reveals that translocation of tRNA on the 30S subunit parallels the swivelling of the 30S head and is coupled to unratcheting of the 30S body. Because the tRNA maintains contact with the peptidyl-tRNA-binding site (P site) on the 30S head and simultaneously establishes interaction with the exit site (E site) on the 30S platform, a novel intra-subunit 'pe/E' hybrid state is formed. This state is stabilized by domain IV of EF-G, which interacts with the swivelled 30S-head conformation. These findings provide direct structural and mechanistic insight into the 'missing link' in terms of tRNA intermediates involved in the universally conserved translocation process. |
リンク | Nature / PubMed:21124459 / PubMed Central |
手法 | EM (単粒子) |
解像度 | 7.6 - 7.8 Å |
構造データ | |
化合物 | ChemComp-FUA: ChemComp-GDP: |
由来 |
|
キーワード | RIBOSOME (リボソーム) / TRANSLATION (翻訳 (生物学)) / ELONGATION CYCLE / TRNA TRANSLOCATION |