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Visualizing the transfer‐messenger RNA as the ribosome resumes translation
Author(s) -
Fu Jie,
Hashem Yaser,
Wower Iwona,
Lei Jianlin,
Liao Hstau Y,
Zwieb Christian,
Wower Jacek,
Frank Joachim
Publication year - 2010
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1038/emboj.2010.255
Subject(s) - biology , translation (biology) , ribosome , transfer rna , messenger rna , computational biology , genetics , rna , microbiology and biotechnology , gene
Bacterial ribosomes stalled by truncated mRNAs are rescued by transfer‐messenger RNA (tmRNA), a dual‐function molecule that contains a tRNA‐like domain (TLD) and an internal open reading frame (ORF). Occupying the empty A site with its TLD, the tmRNA enters the ribosome with the help of elongation factor Tu and a protein factor called small protein B (SmpB), and switches the translation to its own ORF. In this study, using cryo‐electron microscopy, we obtained the first structure of an in vivo ‐formed complex containing ribosome and the tmRNA at the point where the TLD is accommodated into the ribosomal P site. We show that tmRNA maintains a stable ‘arc and fork’ structure on the ribosome when its TLD moves to the ribosomal P site and translation resumes on its ORF. Based on the density map, we built an atomic model, which suggests that SmpB interacts with the five nucleotides immediately upstream of the resume codon, thereby determining the correct selection of the reading frame on the ORF of tmRNA.