EF4 disengages the peptidyl-tRNA CCA end and facilitates back-translocation on the 70S ribosome.
Nat Struct Mol Biol
; 23(2): 125-31, 2016 Feb.
Article
em En
| MEDLINE
| ID: mdl-26809121
ABSTRACT
EF4 catalyzes tRNA back-translocation through an unknown mechanism. We report cryo-EM structures of Escherichia coli EF4 in post- and pretranslocational ribosomes (Post- and Pre-EF4) at 3.7- and 3.2-Å resolution, respectively. In Post-EF4, peptidyl-tRNA occupies the peptidyl (P) site, but the interaction between its CCA end and the P loop is disrupted. In Pre-EF4, the peptidyl-tRNA assumes a unique position near the aminoacyl (A) site, denoted the A site/EF4 bound (A/4) site, with a large displacement at its acceptor arm. Mutagenesis analyses suggest that a specific region in the EF4 C-terminal domain (CTD) interferes with base-pairing between the peptidyl-tRNA 3'-CCA and the P loop, whereas the EF4 CTD enhances peptidyl-tRNA interaction at the A/4 site. Therefore, EF4 induces back-translocation by disengaging the tRNA's CCA end from the peptidyl transferase center of the translating ribosome.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Aminoacil-RNA de Transferência
/
Fatores de Iniciação de Peptídeos
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Proteínas de Escherichia coli
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Escherichia coli
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Subunidades Ribossômicas Maiores de Bactérias
Tipo de estudo:
Prognostic_studies
Idioma:
En
Revista:
Nat Struct Mol Biol
Assunto da revista:
BIOLOGIA MOLECULAR
Ano de publicação:
2016
Tipo de documento:
Article
País de afiliação:
China