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Interface between 40S exit channel protein uS7/Rps5 and eIF2α modulates start codon recognition in vivo

The eukaryotic pre-initiation complex (PIC) bearing the eIF2·GTP·Met-tRNA(i)(Met) ternary complex (TC) scans the mRNA for an AUG codon in favorable context. AUG recognition evokes rearrangement of the PIC from an open, scanning to a closed, arrested conformation. Cryo-EM reconstructions of yeast PIC...

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Autores principales: Visweswaraiah, Jyothsna, Hinnebusch, Alan G
Formato: Online Artículo Texto
Lenguaje:English
Publicado: eLife Sciences Publications, Ltd 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5323038/
https://www.ncbi.nlm.nih.gov/pubmed/28169832
http://dx.doi.org/10.7554/eLife.22572
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author Visweswaraiah, Jyothsna
Hinnebusch, Alan G
author_facet Visweswaraiah, Jyothsna
Hinnebusch, Alan G
author_sort Visweswaraiah, Jyothsna
collection PubMed
description The eukaryotic pre-initiation complex (PIC) bearing the eIF2·GTP·Met-tRNA(i)(Met) ternary complex (TC) scans the mRNA for an AUG codon in favorable context. AUG recognition evokes rearrangement of the PIC from an open, scanning to a closed, arrested conformation. Cryo-EM reconstructions of yeast PICs suggest remodeling of the interface between 40S protein Rps5/uS7 and eIF2α between open and closed states; however, its importance was unknown. uS7 substitutions disrupting eIF2α contacts favored in the open complex increase initiation at suboptimal sites, and uS7-S223D stabilizes TC binding to PICs reconstituted with a UUG start codon, indicating inappropriate rearrangement to the closed state. Conversely, uS7-D215 substitutions, perturbing uS7-eIF2α interaction in the closed state, confer the opposite phenotypes of hyperaccuracy and (for D215L) accelerated TC dissociation from reconstituted PICs. Thus, remodeling of the uS7/eIF2α interface appears to stabilize first the open, and then the closed state of the PIC to promote accurate AUG selection in vivo. DOI: http://dx.doi.org/10.7554/eLife.22572.001
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spelling pubmed-53230382017-02-27 Interface between 40S exit channel protein uS7/Rps5 and eIF2α modulates start codon recognition in vivo Visweswaraiah, Jyothsna Hinnebusch, Alan G eLife Biochemistry The eukaryotic pre-initiation complex (PIC) bearing the eIF2·GTP·Met-tRNA(i)(Met) ternary complex (TC) scans the mRNA for an AUG codon in favorable context. AUG recognition evokes rearrangement of the PIC from an open, scanning to a closed, arrested conformation. Cryo-EM reconstructions of yeast PICs suggest remodeling of the interface between 40S protein Rps5/uS7 and eIF2α between open and closed states; however, its importance was unknown. uS7 substitutions disrupting eIF2α contacts favored in the open complex increase initiation at suboptimal sites, and uS7-S223D stabilizes TC binding to PICs reconstituted with a UUG start codon, indicating inappropriate rearrangement to the closed state. Conversely, uS7-D215 substitutions, perturbing uS7-eIF2α interaction in the closed state, confer the opposite phenotypes of hyperaccuracy and (for D215L) accelerated TC dissociation from reconstituted PICs. Thus, remodeling of the uS7/eIF2α interface appears to stabilize first the open, and then the closed state of the PIC to promote accurate AUG selection in vivo. DOI: http://dx.doi.org/10.7554/eLife.22572.001 eLife Sciences Publications, Ltd 2017-02-07 /pmc/articles/PMC5323038/ /pubmed/28169832 http://dx.doi.org/10.7554/eLife.22572 Text en http://creativecommons.org/publicdomain/zero/1.0/ This is an open-access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication (http://creativecommons.org/publicdomain/zero/1.0/) .
spellingShingle Biochemistry
Visweswaraiah, Jyothsna
Hinnebusch, Alan G
Interface between 40S exit channel protein uS7/Rps5 and eIF2α modulates start codon recognition in vivo
title Interface between 40S exit channel protein uS7/Rps5 and eIF2α modulates start codon recognition in vivo
title_full Interface between 40S exit channel protein uS7/Rps5 and eIF2α modulates start codon recognition in vivo
title_fullStr Interface between 40S exit channel protein uS7/Rps5 and eIF2α modulates start codon recognition in vivo
title_full_unstemmed Interface between 40S exit channel protein uS7/Rps5 and eIF2α modulates start codon recognition in vivo
title_short Interface between 40S exit channel protein uS7/Rps5 and eIF2α modulates start codon recognition in vivo
title_sort interface between 40s exit channel protein us7/rps5 and eif2α modulates start codon recognition in vivo
topic Biochemistry
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5323038/
https://www.ncbi.nlm.nih.gov/pubmed/28169832
http://dx.doi.org/10.7554/eLife.22572
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