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Ribosome rearrangements at the onset of translational bypassing.

ABSTRACT: Bypassing is a recoding event that leads to the translation of two distal open reading frames into a single polypeptide chain. We present the structure of a translating ribosome stalled at the bypassing take-off site of gene 60 of bacteriophage T4. The nascent peptide in the exit tunnel anchors the P-site peptidyl-tRNAGly to the ribosome and locks an inactive conformation of the peptidyl transferase center (PTC). The mRNA forms a short dynamic hairpin in the decoding site. The ribosomal subunits adopt a rolling conformation in which the rotation of the small subunit around its long axis causes the opening of the A-site region. Together, PTC conformation and mRNA structure safeguard against premature termination and read-through of the stop codon and reconfigure the ribosome to a state poised for take-off and sliding along the noncoding mRNA gap.

SUBMITTER: Agirrezabala X

PROVIDER: S-EPMC5462505 | biostudies-literature | 2017 Jun

REPOSITORIES: biostudies-literature

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Ribosome rearrangements at the onset of translational bypassing.

Agirrezabala Xabier X Samatova Ekaterina E Klimova Mariia M Zamora Miguel M Gil-Carton David D Rodnina Marina V MV Valle Mikel M

Science advances 20170607 6

Bypassing is a recoding event that leads to the translation of two distal open reading frames into a single polypeptide chain. We present the structure of a translating ribosome stalled at the bypassing take-off site of <i>gene 60</i> of bacteriophage T4. The nascent peptide in the exit tunnel anchors the P-site peptidyl-tRNA<sup>Gly</sup> to the ribosome and locks an inactive conformation of the peptidyl transferase center (PTC). The mRNA forms a short dynamic hairpin in the decoding site. The ...[more]

PMID: 28630923

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