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Single-molecule chemo-mechanical unfolding reveals multiple transition state barriers in a small single-domain protein

A fundamental question in protein folding is whether proteins fold through one or multiple trajectories. While most experiments indicate a single pathway, simulations suggest proteins can fold through many parallel pathways. Here, we use a combination of chemical denaturant, mechanical force and sit...

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Detalles Bibliográficos
Autores principales: Guinn, Emily J., Jagannathan, Bharat, Marqusee, Susan
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Pub. Group 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4410640/
https://www.ncbi.nlm.nih.gov/pubmed/25882479
http://dx.doi.org/10.1038/ncomms7861
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author Guinn, Emily J.
Jagannathan, Bharat
Marqusee, Susan
author_facet Guinn, Emily J.
Jagannathan, Bharat
Marqusee, Susan
author_sort Guinn, Emily J.
collection PubMed
description A fundamental question in protein folding is whether proteins fold through one or multiple trajectories. While most experiments indicate a single pathway, simulations suggest proteins can fold through many parallel pathways. Here, we use a combination of chemical denaturant, mechanical force and site-directed mutations to demonstrate the presence of multiple unfolding pathways in a simple, two-state folding protein. We show that these multiple pathways have structurally different transition states, and that seemingly small changes in protein sequence and environment can strongly modulate the flux between the pathways. These results suggest that in vivo, the crowded cellular environment could strongly influence the mechanisms of protein folding and unfolding. Our study resolves the apparent dichotomy between experimental and theoretical studies, and highlights the advantage of using a multipronged approach to reveal the complexities of a protein's free-energy landscape.
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spelling pubmed-44106402015-05-08 Single-molecule chemo-mechanical unfolding reveals multiple transition state barriers in a small single-domain protein Guinn, Emily J. Jagannathan, Bharat Marqusee, Susan Nat Commun Article A fundamental question in protein folding is whether proteins fold through one or multiple trajectories. While most experiments indicate a single pathway, simulations suggest proteins can fold through many parallel pathways. Here, we use a combination of chemical denaturant, mechanical force and site-directed mutations to demonstrate the presence of multiple unfolding pathways in a simple, two-state folding protein. We show that these multiple pathways have structurally different transition states, and that seemingly small changes in protein sequence and environment can strongly modulate the flux between the pathways. These results suggest that in vivo, the crowded cellular environment could strongly influence the mechanisms of protein folding and unfolding. Our study resolves the apparent dichotomy between experimental and theoretical studies, and highlights the advantage of using a multipronged approach to reveal the complexities of a protein's free-energy landscape. Nature Pub. Group 2015-04-17 /pmc/articles/PMC4410640/ /pubmed/25882479 http://dx.doi.org/10.1038/ncomms7861 Text en Copyright © 2015, Nature Publishing Group, a division of Macmillan Publishers Limited. All Rights Reserved. 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
Guinn, Emily J.
Jagannathan, Bharat
Marqusee, Susan
Single-molecule chemo-mechanical unfolding reveals multiple transition state barriers in a small single-domain protein
title Single-molecule chemo-mechanical unfolding reveals multiple transition state barriers in a small single-domain protein
title_full Single-molecule chemo-mechanical unfolding reveals multiple transition state barriers in a small single-domain protein
title_fullStr Single-molecule chemo-mechanical unfolding reveals multiple transition state barriers in a small single-domain protein
title_full_unstemmed Single-molecule chemo-mechanical unfolding reveals multiple transition state barriers in a small single-domain protein
title_short Single-molecule chemo-mechanical unfolding reveals multiple transition state barriers in a small single-domain protein
title_sort single-molecule chemo-mechanical unfolding reveals multiple transition state barriers in a small single-domain protein
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4410640/
https://www.ncbi.nlm.nih.gov/pubmed/25882479
http://dx.doi.org/10.1038/ncomms7861
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