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
in 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.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
RNA, Transfer, Amino Acyl
/
Peptide Initiation Factors
/
Escherichia coli Proteins
/
Escherichia coli
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Ribosome Subunits, Large, Bacterial
Type of study:
Prognostic_studies
Language:
En
Journal:
Nat Struct Mol Biol
Journal subject:
BIOLOGIA MOLECULAR
Year:
2016
Document type:
Article
Affiliation country:
China
Publication country:
EEUU
/
ESTADOS UNIDOS
/
ESTADOS UNIDOS DA AMERICA
/
EUA
/
UNITED STATES
/
UNITED STATES OF AMERICA
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US
/
USA