7k54
From Proteopedia
Mid-translocated +1-frameshifting(CCC-A) complex with EF-G and GDPCP (Structure II-FS)
Structural highlights
FunctionRS7_ECOLI One of the primary rRNA binding proteins, it binds directly to 16S rRNA where it nucleates assembly of the head domain of the 30S subunit. Is located at the subunit interface close to the decoding center, where it has been shown to contact mRNA. Has been shown to contact tRNA in both the P and E sites; it probably blocks exit of the E site tRNA.[1] Protein S7 is also a translational repressor protein; it regulates the expression of the str operon members to different degrees by binding to its mRNA.[2] Publication Abstract from PubMedFrameshifting 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. See AlsoReferences
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