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The different faces of mass action in virus assembly

The spontaneous encapsulation of genomic and non-genomic polyanions by coat proteins of simple icosahedral viruses is driven, in the first instance, by electrostatic interactions with polycationic RNA binding domains on these proteins. The efficiency with which the polyanions can be encapsulated in...

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Autores principales: van der Holst, Bart, Kegel, Willem K., Zandi, Roya, van der Schoot, Paul
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Springer Netherlands 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5928020/
https://www.ncbi.nlm.nih.gov/pubmed/29616429
http://dx.doi.org/10.1007/s10867-018-9487-6
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author van der Holst, Bart
Kegel, Willem K.
Zandi, Roya
van der Schoot, Paul
author_facet van der Holst, Bart
Kegel, Willem K.
Zandi, Roya
van der Schoot, Paul
author_sort van der Holst, Bart
collection PubMed
description The spontaneous encapsulation of genomic and non-genomic polyanions by coat proteins of simple icosahedral viruses is driven, in the first instance, by electrostatic interactions with polycationic RNA binding domains on these proteins. The efficiency with which the polyanions can be encapsulated in vitro, and presumably also in vivo, must in addition be governed by the loss of translational and mixing entropy associated with co-assembly, at least if this co-assembly constitutes a reversible process. These forms of entropy counteract the impact of attractive interactions between the constituents and hence they counteract complexation. By invoking mass action-type arguments and a simple model describing electrostatic interactions, we show how these forms of entropy might settle the competition between negatively charged polymers of different molecular weights for co-assembly with the coat proteins. In direct competition, mass action turns out to strongly work against the encapsulation of RNAs that are significantly shorter, which is typically the case for non-viral (host) RNAs. We also find that coat proteins favor forming virus particles over nonspecific binding to other proteins in the cytosol even if these are present in vast excess. Our results rationalize a number of recent in vitro co-assembly experiments showing that short polyanions are less effective at attracting virus coat proteins to form virus-like particles than long ones do, even if both are present at equal weight concentrations in the assembly mixture.
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spelling pubmed-59280202018-05-03 The different faces of mass action in virus assembly van der Holst, Bart Kegel, Willem K. Zandi, Roya van der Schoot, Paul J Biol Phys Original Paper The spontaneous encapsulation of genomic and non-genomic polyanions by coat proteins of simple icosahedral viruses is driven, in the first instance, by electrostatic interactions with polycationic RNA binding domains on these proteins. The efficiency with which the polyanions can be encapsulated in vitro, and presumably also in vivo, must in addition be governed by the loss of translational and mixing entropy associated with co-assembly, at least if this co-assembly constitutes a reversible process. These forms of entropy counteract the impact of attractive interactions between the constituents and hence they counteract complexation. By invoking mass action-type arguments and a simple model describing electrostatic interactions, we show how these forms of entropy might settle the competition between negatively charged polymers of different molecular weights for co-assembly with the coat proteins. In direct competition, mass action turns out to strongly work against the encapsulation of RNAs that are significantly shorter, which is typically the case for non-viral (host) RNAs. We also find that coat proteins favor forming virus particles over nonspecific binding to other proteins in the cytosol even if these are present in vast excess. Our results rationalize a number of recent in vitro co-assembly experiments showing that short polyanions are less effective at attracting virus coat proteins to form virus-like particles than long ones do, even if both are present at equal weight concentrations in the assembly mixture. Springer Netherlands 2018-04-03 2018-06 /pmc/articles/PMC5928020/ /pubmed/29616429 http://dx.doi.org/10.1007/s10867-018-9487-6 Text en © The Author(s) 2018 Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
spellingShingle Original Paper
van der Holst, Bart
Kegel, Willem K.
Zandi, Roya
van der Schoot, Paul
The different faces of mass action in virus assembly
title The different faces of mass action in virus assembly
title_full The different faces of mass action in virus assembly
title_fullStr The different faces of mass action in virus assembly
title_full_unstemmed The different faces of mass action in virus assembly
title_short The different faces of mass action in virus assembly
title_sort different faces of mass action in virus assembly
topic Original Paper
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5928020/
https://www.ncbi.nlm.nih.gov/pubmed/29616429
http://dx.doi.org/10.1007/s10867-018-9487-6
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