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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...
Autores principales: | , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
eLife Sciences Publications, Ltd
2020
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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. |
format | Online Article Text |
id | pubmed-7234808 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2020 |
publisher | eLife Sciences Publications, Ltd |
record_format | MEDLINE/PubMed |
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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