Mutations in domain IV of elongation factor EF-G confer -1 frameshifting
| Autor: | Jie Zhou, Jake Cozy, Charlotte A. Nelson, Harry F. Noller, Gillian Rexroad, Calvin S. Leung, Laura Lancaster, Dustin Niblett |
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| Rok vydání: | 2020 |
| Předmět: |
Reading Frames
Recombinant Fusion Proteins Mutant Peptide Chain Elongation Translational Chromosomal translocation Biology Ribosome Protein Structure Secondary Article 03 medical and health sciences Protein Domains RNA Transfer Anticodon Escherichia coli 30S Histidine Protein Interaction Domains and Motifs RNA Messenger Codon Molecular Biology 030304 developmental biology 0303 health sciences Binding Sites 030302 biochemistry & molecular biology RNA Frameshifting Ribosomal Peptide Elongation Factor G Cell biology Elongation factor Transfer RNA Mutation EF-G Oligopeptides Ribosomes Protein Binding |
| Zdroj: | RNA |
| ISSN: | 1469-9001 |
| Popis: | A recent crystal structure of a ribosome complex undergoing partial translocation in the absence of elongation factor EF-G showed disruption of codon–anticodon pairing and slippage of the reading frame by −1, directly implicating EF-G in preservation of the translational reading frame. Among mutations identified in a random screen for dominant-lethal mutations of EF-G were a cluster of six that map to the tip of domain IV, which has been shown to contact the codon–anticodon duplex in trapped translocation intermediates. In vitro synthesis of a full-length protein using these mutant EF-Gs revealed dramatically increased −1 frameshifting, providing new evidence for a role for domain IV of EF-G in maintaining the reading frame. These mutations also caused decreased rates of mRNA translocation and rotational movement of the head and body domains of the 30S ribosomal subunit during translocation. Our results are in general agreement with recent findings from Rodnina and coworkers based on in vitro translation of an oligopeptide using EF-Gs containing mutations at two positions in domain IV, who found an inverse correlation between the degree of frameshifting and rates of translocation. Four of our six mutations are substitutions at positions that interact with the translocating tRNA, in each case contacting the RNA backbone of the anticodon loop. We suggest that EF-G helps to preserve the translational reading frame by preventing uncoupled movement of the tRNA through these contacts; a further possibility is that these interactions may stabilize a conformation of the anticodon that favors base-pairing with its codon. |
| Databáze: | OpenAIRE |
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