Frameshifting of mRNA during translation provides a strategy to expand the coding repertoire of cells and viruses. How and where in the elongation cycle +1-frameshifting occurs remains poorly understood. We describe seven ~3.5-Å-resolution cryo-EM structures of 70S ribosome complexes, allowing visualization of elongation and translocation by the GTPase elongation factor G (EF-G). Four structures with a + 1-frameshifting-prone mRNA reveal that frameshifting takes place during translocation of tRNA and mRNA. Prior to EF-G binding, the pre-translocation complex features an in-frame tRNA-mRNA pairing in the A site. In the partially translocated structure with EF-G•GDPCP, the tRNA shifts to the +1-frame near the P site, rendering the freed mRNA base to bulge between the P and E sites and to stack on the 16S rRNA nucleotide G926. The ribosome remains frameshifted in the nearly post-translocation state. Our findings demonstrate that the ribosome and EF-G cooperate to induce +1 frameshifting during tRNA-mRNA translocation.

• MeSH
• biokatalýza MeSH
• elektronová kryomikroskopie MeSH
• elongace translace peptidového řetězce genetika   MeSH
• elongační faktor G chemie   genetika   metabolismus   MeSH
• Escherichia coli genetika   metabolismus   MeSH
• konformace nukleové kyseliny MeSH
• konformace proteinů MeSH
• messenger RNA chemie   genetika   metabolismus   MeSH
• molekulární modely MeSH
• posun čtecího rámce na ribozómech genetika   MeSH
• proteiny z Escherichia coli chemie   genetika   metabolismus   MeSH
• ribozomy genetika   metabolismus   ultrastruktura   MeSH
• RNA ribozomální 16S chemie   genetika   metabolismus   MeSH
• RNA transferová chemie   genetika   metabolismus   MeSH
• tRNA-methyltransferasy genetika   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH