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Unfolding of DNA quadruplexes induced by HIV-1 nucleocapsid protein

The human immunodeficiency virus type 1 nucleocapsid protein (NC) is a nucleic acid chaperone that catalyzes the rearrangement of nucleic acids into their thermodynamically most stable structures. In the present study, a combination of optical and thermodynamic techniques were used to characterize t...

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Autores principales: Kankia, Besik I., Barany, George, Musier-Forsyth, Karin
Formato: Texto
Lenguaje:English
Publicado: Oxford University Press 2005
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1182697/
https://www.ncbi.nlm.nih.gov/pubmed/16077025
http://dx.doi.org/10.1093/nar/gki741
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author Kankia, Besik I.
Barany, George
Musier-Forsyth, Karin
author_facet Kankia, Besik I.
Barany, George
Musier-Forsyth, Karin
author_sort Kankia, Besik I.
collection PubMed
description The human immunodeficiency virus type 1 nucleocapsid protein (NC) is a nucleic acid chaperone that catalyzes the rearrangement of nucleic acids into their thermodynamically most stable structures. In the present study, a combination of optical and thermodynamic techniques were used to characterize the influence of NC on the secondary structure, thermal stability and energetics of monomolecular DNA quadruplexes formed by the sequence d(GGTTGGTGTGGTTGG) in the presence of K(+) or Sr(2+). Circular dichroism studies demonstrate that NC effectively unfolds the quadruplexes. Studies carried out with NC variants suggest that destabilization is mediated by the zinc fingers of NC. Calorimetric studies reveal that NC destabilization is enthalpic in origin, probably owing to unstacking of the G-quartets upon protein binding. In contrast, parallel studies performed on a related DNA duplex reveal that under conditions where NC readily destabilizes and unfolds the quadruplexes, its effect on the DNA duplex is much less pronounced. The differences in NC's ability to destabilize quadruplex versus duplex is in accordance with the higher ΔG of melting for the latter, and with the inverse correlation between nucleic acid stability and the destabilizing activity of NC.
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spelling pubmed-11826972005-08-05 Unfolding of DNA quadruplexes induced by HIV-1 nucleocapsid protein Kankia, Besik I. Barany, George Musier-Forsyth, Karin Nucleic Acids Res Article The human immunodeficiency virus type 1 nucleocapsid protein (NC) is a nucleic acid chaperone that catalyzes the rearrangement of nucleic acids into their thermodynamically most stable structures. In the present study, a combination of optical and thermodynamic techniques were used to characterize the influence of NC on the secondary structure, thermal stability and energetics of monomolecular DNA quadruplexes formed by the sequence d(GGTTGGTGTGGTTGG) in the presence of K(+) or Sr(2+). Circular dichroism studies demonstrate that NC effectively unfolds the quadruplexes. Studies carried out with NC variants suggest that destabilization is mediated by the zinc fingers of NC. Calorimetric studies reveal that NC destabilization is enthalpic in origin, probably owing to unstacking of the G-quartets upon protein binding. In contrast, parallel studies performed on a related DNA duplex reveal that under conditions where NC readily destabilizes and unfolds the quadruplexes, its effect on the DNA duplex is much less pronounced. The differences in NC's ability to destabilize quadruplex versus duplex is in accordance with the higher ΔG of melting for the latter, and with the inverse correlation between nucleic acid stability and the destabilizing activity of NC. Oxford University Press 2005 2005-08-02 /pmc/articles/PMC1182697/ /pubmed/16077025 http://dx.doi.org/10.1093/nar/gki741 Text en © The Author 2005. Published by Oxford University Press. All rights reserved
spellingShingle Article
Kankia, Besik I.
Barany, George
Musier-Forsyth, Karin
Unfolding of DNA quadruplexes induced by HIV-1 nucleocapsid protein
title Unfolding of DNA quadruplexes induced by HIV-1 nucleocapsid protein
title_full Unfolding of DNA quadruplexes induced by HIV-1 nucleocapsid protein
title_fullStr Unfolding of DNA quadruplexes induced by HIV-1 nucleocapsid protein
title_full_unstemmed Unfolding of DNA quadruplexes induced by HIV-1 nucleocapsid protein
title_short Unfolding of DNA quadruplexes induced by HIV-1 nucleocapsid protein
title_sort unfolding of dna quadruplexes induced by hiv-1 nucleocapsid protein
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1182697/
https://www.ncbi.nlm.nih.gov/pubmed/16077025
http://dx.doi.org/10.1093/nar/gki741
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