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Cryo-EM structure in situ reveals a molecular switch that safeguards virus against genome loss

The portal protein is a key component of many double-stranded DNA viruses, governing capsid assembly and genome packaging. Twelve subunits of the portal protein define a tunnel, through which DNA is translocated into the capsid. It is unknown how the portal protein functions as a gatekeeper, prevent...

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Autores principales: Bayfield, Oliver W, Steven, Alasdair C, Antson, Alfred A
Formato: Online Artículo Texto
Lenguaje:English
Publicado: eLife Sciences Publications, Ltd 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7234808/
https://www.ncbi.nlm.nih.gov/pubmed/32286226
http://dx.doi.org/10.7554/eLife.55517
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author Bayfield, Oliver W
Steven, Alasdair C
Antson, Alfred A
author_facet Bayfield, Oliver W
Steven, Alasdair C
Antson, Alfred A
author_sort Bayfield, Oliver W
collection PubMed
description The portal protein is a key component of many double-stranded DNA viruses, governing capsid assembly and genome packaging. Twelve subunits of the portal protein define a tunnel, through which DNA is translocated into the capsid. It is unknown how the portal protein functions as a gatekeeper, preventing DNA slippage, whilst allowing its passage into the capsid, and how these processes are controlled. A cryo-EM structure of the portal protein of thermostable virus P23-45, determined in situ in its procapsid-bound state, indicates a mechanism that naturally safeguards the virus against genome loss. This occurs via an inversion of the conformation of the loops that define the constriction in the central tunnel, accompanied by a hydrophilic–hydrophobic switch. The structure also shows how translocation of DNA into the capsid could be modulated by a changing mode of protein–protein interactions between portal and capsid, across a symmetry-mismatched interface.
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spelling pubmed-72348082020-05-20 Cryo-EM structure in situ reveals a molecular switch that safeguards virus against genome loss Bayfield, Oliver W Steven, Alasdair C Antson, Alfred A eLife Structural Biology and Molecular Biophysics The portal protein is a key component of many double-stranded DNA viruses, governing capsid assembly and genome packaging. Twelve subunits of the portal protein define a tunnel, through which DNA is translocated into the capsid. It is unknown how the portal protein functions as a gatekeeper, preventing DNA slippage, whilst allowing its passage into the capsid, and how these processes are controlled. A cryo-EM structure of the portal protein of thermostable virus P23-45, determined in situ in its procapsid-bound state, indicates a mechanism that naturally safeguards the virus against genome loss. This occurs via an inversion of the conformation of the loops that define the constriction in the central tunnel, accompanied by a hydrophilic–hydrophobic switch. The structure also shows how translocation of DNA into the capsid could be modulated by a changing mode of protein–protein interactions between portal and capsid, across a symmetry-mismatched interface. eLife Sciences Publications, Ltd 2020-04-14 /pmc/articles/PMC7234808/ /pubmed/32286226 http://dx.doi.org/10.7554/eLife.55517 Text en http://creativecommons.org/publicdomain/zero/1.0/ 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 Structural Biology and Molecular Biophysics
Bayfield, Oliver W
Steven, Alasdair C
Antson, Alfred A
Cryo-EM structure in situ reveals a molecular switch that safeguards virus against genome loss
title Cryo-EM structure in situ reveals a molecular switch that safeguards virus against genome loss
title_full Cryo-EM structure in situ reveals a molecular switch that safeguards virus against genome loss
title_fullStr Cryo-EM structure in situ reveals a molecular switch that safeguards virus against genome loss
title_full_unstemmed Cryo-EM structure in situ reveals a molecular switch that safeguards virus against genome loss
title_short Cryo-EM structure in situ reveals a molecular switch that safeguards virus against genome loss
title_sort cryo-em structure in situ reveals a molecular switch that safeguards virus against genome loss
topic Structural Biology and Molecular Biophysics
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7234808/
https://www.ncbi.nlm.nih.gov/pubmed/32286226
http://dx.doi.org/10.7554/eLife.55517
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