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Chemical and Thermal Unfolding of a Global Staphylococcal Virulence Regulator with a Flexible C-Terminal End
SarA, a Staphylococcus aureus-specific dimeric protein, modulates the expression of numerous proteins including various virulence factors. Interestingly, S. aureus synthesizes multiple SarA paralogs seemingly for optimizing the expression of its virulence factors. To understand the domain structure/...
Autores principales: | , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Public Library of Science
2015
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4379015/ https://www.ncbi.nlm.nih.gov/pubmed/25822635 http://dx.doi.org/10.1371/journal.pone.0122168 |
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author | Mahapa, Avisek Mandal, Sukhendu Biswas, Anindya Jana, Biswanath Polley, Soumitra Sau, Subrata Sau, Keya |
author_facet | Mahapa, Avisek Mandal, Sukhendu Biswas, Anindya Jana, Biswanath Polley, Soumitra Sau, Subrata Sau, Keya |
author_sort | Mahapa, Avisek |
collection | PubMed |
description | SarA, a Staphylococcus aureus-specific dimeric protein, modulates the expression of numerous proteins including various virulence factors. Interestingly, S. aureus synthesizes multiple SarA paralogs seemingly for optimizing the expression of its virulence factors. To understand the domain structure/flexibility and the folding/unfolding mechanism of the SarA protein family, we have studied a recombinant SarA (designated rSarA) using various in vitro probes. Limited proteolysis of rSarA and the subsequent analysis of the resulting protein fragments suggested it to be a single-domain protein with a long, flexible C-terminal end. rSarA was unfolded by different mechanisms in the presence of different chemical and physical denaturants. While urea-induced unfolding of rSarA occurred successively via the formation of a dimeric and a monomeric intermediate, GdnCl-induced unfolding of this protein proceeded through the production of two dimeric intermediates. The surface hydrophobicity and the structures of the intermediates were not identical and also differed significantly from those of native rSarA. Of the intermediates, the GdnCl-generated intermediates not only possessed a molten globule-like structure but also exhibited resistance to dissociation during their unfolding. Compared to the native rSarA, the intermediate that was originated at lower GdnCl concentration carried a compact shape, whereas, other intermediates owned a swelled shape. The chemical-induced unfolding, unlike thermal unfolding of rSarA, was completely reversible in nature. |
format | Online Article Text |
id | pubmed-4379015 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2015 |
publisher | Public Library of Science |
record_format | MEDLINE/PubMed |
spelling | pubmed-43790152015-04-09 Chemical and Thermal Unfolding of a Global Staphylococcal Virulence Regulator with a Flexible C-Terminal End Mahapa, Avisek Mandal, Sukhendu Biswas, Anindya Jana, Biswanath Polley, Soumitra Sau, Subrata Sau, Keya PLoS One Research Article SarA, a Staphylococcus aureus-specific dimeric protein, modulates the expression of numerous proteins including various virulence factors. Interestingly, S. aureus synthesizes multiple SarA paralogs seemingly for optimizing the expression of its virulence factors. To understand the domain structure/flexibility and the folding/unfolding mechanism of the SarA protein family, we have studied a recombinant SarA (designated rSarA) using various in vitro probes. Limited proteolysis of rSarA and the subsequent analysis of the resulting protein fragments suggested it to be a single-domain protein with a long, flexible C-terminal end. rSarA was unfolded by different mechanisms in the presence of different chemical and physical denaturants. While urea-induced unfolding of rSarA occurred successively via the formation of a dimeric and a monomeric intermediate, GdnCl-induced unfolding of this protein proceeded through the production of two dimeric intermediates. The surface hydrophobicity and the structures of the intermediates were not identical and also differed significantly from those of native rSarA. Of the intermediates, the GdnCl-generated intermediates not only possessed a molten globule-like structure but also exhibited resistance to dissociation during their unfolding. Compared to the native rSarA, the intermediate that was originated at lower GdnCl concentration carried a compact shape, whereas, other intermediates owned a swelled shape. The chemical-induced unfolding, unlike thermal unfolding of rSarA, was completely reversible in nature. Public Library of Science 2015-03-30 /pmc/articles/PMC4379015/ /pubmed/25822635 http://dx.doi.org/10.1371/journal.pone.0122168 Text en © 2015 Mahapa et al http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited. |
spellingShingle | Research Article Mahapa, Avisek Mandal, Sukhendu Biswas, Anindya Jana, Biswanath Polley, Soumitra Sau, Subrata Sau, Keya Chemical and Thermal Unfolding of a Global Staphylococcal Virulence Regulator with a Flexible C-Terminal End |
title | Chemical and Thermal Unfolding of a Global Staphylococcal Virulence Regulator with a Flexible C-Terminal End |
title_full | Chemical and Thermal Unfolding of a Global Staphylococcal Virulence Regulator with a Flexible C-Terminal End |
title_fullStr | Chemical and Thermal Unfolding of a Global Staphylococcal Virulence Regulator with a Flexible C-Terminal End |
title_full_unstemmed | Chemical and Thermal Unfolding of a Global Staphylococcal Virulence Regulator with a Flexible C-Terminal End |
title_short | Chemical and Thermal Unfolding of a Global Staphylococcal Virulence Regulator with a Flexible C-Terminal End |
title_sort | chemical and thermal unfolding of a global staphylococcal virulence regulator with a flexible c-terminal end |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4379015/ https://www.ncbi.nlm.nih.gov/pubmed/25822635 http://dx.doi.org/10.1371/journal.pone.0122168 |
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