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Single Molecular Demonstration of Modulating Charge Inversion of DNA

Charge inversion of DNA is a counterintuitive phenomenon in which the effective charge of DNA switches its sign from negative to positive in the presence of multivalent counterions. The underlying microscopic mechanism is still controversial whether it is driven by a specific chemical affinity or el...

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Autores principales: Wang, Yanwei, Wang, Ruxia, Cao, Bozhi, Guo, Zilong, Yang, Guangcan
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5144137/
https://www.ncbi.nlm.nih.gov/pubmed/27929107
http://dx.doi.org/10.1038/srep38628
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author Wang, Yanwei
Wang, Ruxia
Cao, Bozhi
Guo, Zilong
Yang, Guangcan
author_facet Wang, Yanwei
Wang, Ruxia
Cao, Bozhi
Guo, Zilong
Yang, Guangcan
author_sort Wang, Yanwei
collection PubMed
description Charge inversion of DNA is a counterintuitive phenomenon in which the effective charge of DNA switches its sign from negative to positive in the presence of multivalent counterions. The underlying microscopic mechanism is still controversial whether it is driven by a specific chemical affinity or electrostatic ion correlation. It is well known that DNA shows no charge inversion in normal aqueous solution of trivalent counterions though they can induce the conformational compaction of DNA. However, in the same trivalent counterion condition, we demonstrate for the first time the occurrence of DNA charge inversion by decreasing the dielectric constant of solution to make the electrophoretic mobility of DNA increase from a negative value to a positive value. In contrast, the charge inversion of DNA induced by quadrivalent counterions can be canceled out by increasing the dielectric constant of solution. The physical modulation of DNA effective charge in two ways unambiguously demonstrates that charge inversion of DNA is a predominantly electrostatic phenomenon driven by the existence of a strongly correlated liquid (SCL) of counterions at the DNA surface. This conclusion is also supported by the measurement of condensing and unraveling forces of DNA condensates by single molecular MT.
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spelling pubmed-51441372016-12-16 Single Molecular Demonstration of Modulating Charge Inversion of DNA Wang, Yanwei Wang, Ruxia Cao, Bozhi Guo, Zilong Yang, Guangcan Sci Rep Article Charge inversion of DNA is a counterintuitive phenomenon in which the effective charge of DNA switches its sign from negative to positive in the presence of multivalent counterions. The underlying microscopic mechanism is still controversial whether it is driven by a specific chemical affinity or electrostatic ion correlation. It is well known that DNA shows no charge inversion in normal aqueous solution of trivalent counterions though they can induce the conformational compaction of DNA. However, in the same trivalent counterion condition, we demonstrate for the first time the occurrence of DNA charge inversion by decreasing the dielectric constant of solution to make the electrophoretic mobility of DNA increase from a negative value to a positive value. In contrast, the charge inversion of DNA induced by quadrivalent counterions can be canceled out by increasing the dielectric constant of solution. The physical modulation of DNA effective charge in two ways unambiguously demonstrates that charge inversion of DNA is a predominantly electrostatic phenomenon driven by the existence of a strongly correlated liquid (SCL) of counterions at the DNA surface. This conclusion is also supported by the measurement of condensing and unraveling forces of DNA condensates by single molecular MT. Nature Publishing Group 2016-12-08 /pmc/articles/PMC5144137/ /pubmed/27929107 http://dx.doi.org/10.1038/srep38628 Text en Copyright © 2016, The Author(s) http://creativecommons.org/licenses/by/4.0/ This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/
spellingShingle Article
Wang, Yanwei
Wang, Ruxia
Cao, Bozhi
Guo, Zilong
Yang, Guangcan
Single Molecular Demonstration of Modulating Charge Inversion of DNA
title Single Molecular Demonstration of Modulating Charge Inversion of DNA
title_full Single Molecular Demonstration of Modulating Charge Inversion of DNA
title_fullStr Single Molecular Demonstration of Modulating Charge Inversion of DNA
title_full_unstemmed Single Molecular Demonstration of Modulating Charge Inversion of DNA
title_short Single Molecular Demonstration of Modulating Charge Inversion of DNA
title_sort single molecular demonstration of modulating charge inversion of dna
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5144137/
https://www.ncbi.nlm.nih.gov/pubmed/27929107
http://dx.doi.org/10.1038/srep38628
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