tRNA Translocation by the Eukaryotic 80S Ribosome and the Impact of GTP Hydrolysis.
Cell Rep
; 25(10): 2676-2688.e7, 2018 12 04.
Article
em En
| MEDLINE
| ID: mdl-30517857
ABSTRACT
Translocation moves the tRNA2â
mRNA module directionally through the ribosome during the elongation phase of protein synthesis. Although translocation is known to entail large conformational changes within both the ribosome and tRNA substrates, the orchestrated events that ensure the speed and fidelity of this critical aspect of the protein synthesis mechanism have not been fully elucidated. Here, we present three high-resolution structures of intermediates of translocation on the mammalian ribosome where, in contrast to bacteria, ribosomal complexes containing the translocase eEF2 and the complete tRNA2â
mRNA module are trapped by the non-hydrolyzable GTP analog GMPPNP. Consistent with the observed structures, single-molecule imaging revealed that GTP hydrolysis principally facilitates rate-limiting, final steps of translocation, which are required for factor dissociation and which are differentially regulated in bacterial and mammalian systems by the rates of deacyl-tRNA dissociation from the E site.
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Base de dados:
MEDLINE
Assunto principal:
Ribossomos
/
RNA de Transferência
/
Guanosina Trifosfato
Idioma:
En
Ano de publicação:
2018
Tipo de documento:
Article
País de afiliação:
Alemanha