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Nodavirus RNA replication crown architecture reveals proto-crown precursor and viral protein A conformational switching

Positive-strand RNA viruses replicate their genomes in virus-induced membrane vesicles, and the resulting RNA replication complexes are a major target for virus control. Nodavirus studies first revealed viral RNA replication proteins forming a 12-fold symmetric “crown” at the vesicle opening to the...

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Autores principales: Zhan, Hong, Unchwaniwala, Nuruddin, Rebolledo-Viveros, Andrea, Pennington, Janice, Horswill, Mark, Broadberry, Roma, Myers, Jonathan, den Boon, Johan A., Grant, Timothy, Ahlquist, Paul
Formato: Online Artículo Texto
Lenguaje:English
Publicado: National Academy of Sciences 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9945985/
https://www.ncbi.nlm.nih.gov/pubmed/36693094
http://dx.doi.org/10.1073/pnas.2217412120
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author Zhan, Hong
Unchwaniwala, Nuruddin
Rebolledo-Viveros, Andrea
Pennington, Janice
Horswill, Mark
Broadberry, Roma
Myers, Jonathan
den Boon, Johan A.
Grant, Timothy
Ahlquist, Paul
author_facet Zhan, Hong
Unchwaniwala, Nuruddin
Rebolledo-Viveros, Andrea
Pennington, Janice
Horswill, Mark
Broadberry, Roma
Myers, Jonathan
den Boon, Johan A.
Grant, Timothy
Ahlquist, Paul
author_sort Zhan, Hong
collection PubMed
description Positive-strand RNA viruses replicate their genomes in virus-induced membrane vesicles, and the resulting RNA replication complexes are a major target for virus control. Nodavirus studies first revealed viral RNA replication proteins forming a 12-fold symmetric “crown” at the vesicle opening to the cytosol, an arrangement recently confirmed to extend to distantly related alphaviruses. Using cryoelectron microscopy (cryo-EM), we show that mature nodavirus crowns comprise two stacked 12-mer rings of multidomain viral RNA replication protein A. Each ring contains an ~19 nm circle of C-proximal polymerase domains, differentiated by strikingly diverged positions of N-proximal RNA capping/membrane binding domains. The lower ring is a “proto-crown” precursor that assembles prior to RNA template recruitment, RNA synthesis, and replication vesicle formation. In this proto-crown, the N-proximal segments interact to form a toroidal central floor, whose 3.1 Å resolution structure reveals many mechanistic details of the RNA capping/membrane binding domains. In the upper ring, cryo-EM fitting indicates that the N-proximal domains extend radially outside the polymerases, forming separated, membrane-binding “legs.” The polymerase and N-proximal domains are connected by a long linker accommodating the conformational switch between the two rings and possibly also polymerase movements associated with RNA synthesis and nonsymmetric electron density in the lower center of mature crowns. The results reveal remarkable viral protein multifunctionality, conformational flexibility, and evolutionary plasticity and insights into (+)RNA virus replication and control.
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spelling pubmed-99459852023-02-23 Nodavirus RNA replication crown architecture reveals proto-crown precursor and viral protein A conformational switching Zhan, Hong Unchwaniwala, Nuruddin Rebolledo-Viveros, Andrea Pennington, Janice Horswill, Mark Broadberry, Roma Myers, Jonathan den Boon, Johan A. Grant, Timothy Ahlquist, Paul Proc Natl Acad Sci U S A Biological Sciences Positive-strand RNA viruses replicate their genomes in virus-induced membrane vesicles, and the resulting RNA replication complexes are a major target for virus control. Nodavirus studies first revealed viral RNA replication proteins forming a 12-fold symmetric “crown” at the vesicle opening to the cytosol, an arrangement recently confirmed to extend to distantly related alphaviruses. Using cryoelectron microscopy (cryo-EM), we show that mature nodavirus crowns comprise two stacked 12-mer rings of multidomain viral RNA replication protein A. Each ring contains an ~19 nm circle of C-proximal polymerase domains, differentiated by strikingly diverged positions of N-proximal RNA capping/membrane binding domains. The lower ring is a “proto-crown” precursor that assembles prior to RNA template recruitment, RNA synthesis, and replication vesicle formation. In this proto-crown, the N-proximal segments interact to form a toroidal central floor, whose 3.1 Å resolution structure reveals many mechanistic details of the RNA capping/membrane binding domains. In the upper ring, cryo-EM fitting indicates that the N-proximal domains extend radially outside the polymerases, forming separated, membrane-binding “legs.” The polymerase and N-proximal domains are connected by a long linker accommodating the conformational switch between the two rings and possibly also polymerase movements associated with RNA synthesis and nonsymmetric electron density in the lower center of mature crowns. The results reveal remarkable viral protein multifunctionality, conformational flexibility, and evolutionary plasticity and insights into (+)RNA virus replication and control. National Academy of Sciences 2023-01-24 2023-01-31 /pmc/articles/PMC9945985/ /pubmed/36693094 http://dx.doi.org/10.1073/pnas.2217412120 Text en Copyright © 2023 the Author(s). Published by PNAS. https://creativecommons.org/licenses/by-nc-nd/4.0/This open access article is distributed under Creative Commons Attribution-NonCommercial-NoDerivatives License 4.0 (CC BY-NC-ND) (https://creativecommons.org/licenses/by-nc-nd/4.0/) .
spellingShingle Biological Sciences
Zhan, Hong
Unchwaniwala, Nuruddin
Rebolledo-Viveros, Andrea
Pennington, Janice
Horswill, Mark
Broadberry, Roma
Myers, Jonathan
den Boon, Johan A.
Grant, Timothy
Ahlquist, Paul
Nodavirus RNA replication crown architecture reveals proto-crown precursor and viral protein A conformational switching
title Nodavirus RNA replication crown architecture reveals proto-crown precursor and viral protein A conformational switching
title_full Nodavirus RNA replication crown architecture reveals proto-crown precursor and viral protein A conformational switching
title_fullStr Nodavirus RNA replication crown architecture reveals proto-crown precursor and viral protein A conformational switching
title_full_unstemmed Nodavirus RNA replication crown architecture reveals proto-crown precursor and viral protein A conformational switching
title_short Nodavirus RNA replication crown architecture reveals proto-crown precursor and viral protein A conformational switching
title_sort nodavirus rna replication crown architecture reveals proto-crown precursor and viral protein a conformational switching
topic Biological Sciences
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9945985/
https://www.ncbi.nlm.nih.gov/pubmed/36693094
http://dx.doi.org/10.1073/pnas.2217412120
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