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Publication Abstract from PubMed

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-A-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.

Structural basis for +1 ribosomal frameshifting during EF-G-catalyzed translocation.,Demo G, Gamper HB, Loveland AB, Masuda I, Carbone CE, Svidritskiy E, Hou YM, Korostelev AA Nat Commun. 2021 Jul 30;12(1):4644. doi: 10.1038/s41467-021-24911-1. PMID:34330903^[3]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.