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Free-energy landscapes of membrane co-translocational protein unfolding

Protein post-translational translocation is found at the plasma membrane of prokaryotes and protein import into organellae. Translocon structures are becoming available, however the dynamics of proteins during membrane translocation remain largely obscure. Here we study, at the single-molecule level...

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Autores principales: Rosen, Christian Bech, Bayley, Hagan, Rodriguez-Larrea, David
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group UK 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7125183/
https://www.ncbi.nlm.nih.gov/pubmed/32246057
http://dx.doi.org/10.1038/s42003-020-0841-4
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author Rosen, Christian Bech
Bayley, Hagan
Rodriguez-Larrea, David
author_facet Rosen, Christian Bech
Bayley, Hagan
Rodriguez-Larrea, David
author_sort Rosen, Christian Bech
collection PubMed
description Protein post-translational translocation is found at the plasma membrane of prokaryotes and protein import into organellae. Translocon structures are becoming available, however the dynamics of proteins during membrane translocation remain largely obscure. Here we study, at the single-molecule level, the folding landscape of a model protein while forced to translocate a transmembrane pore. We use a DNA tag to drive the protein into the α-hemolysin pore under a quantifiable force produced by an applied electric potential. Using a voltage-quench approach we find that the protein fluctuates between the native state and an intermediate in the translocation process at estimated forces as low as 1.9 pN. The fluctuation kinetics provide the free energy landscape as a function of force. We show that our stable, ≈15 k(B)T, substrate can be unfolded and translocated with physiological membrane potentials and that selective divalent cation binding may have a profound effect on the translocation kinetics.
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spelling pubmed-71251832020-04-13 Free-energy landscapes of membrane co-translocational protein unfolding Rosen, Christian Bech Bayley, Hagan Rodriguez-Larrea, David Commun Biol Article Protein post-translational translocation is found at the plasma membrane of prokaryotes and protein import into organellae. Translocon structures are becoming available, however the dynamics of proteins during membrane translocation remain largely obscure. Here we study, at the single-molecule level, the folding landscape of a model protein while forced to translocate a transmembrane pore. We use a DNA tag to drive the protein into the α-hemolysin pore under a quantifiable force produced by an applied electric potential. Using a voltage-quench approach we find that the protein fluctuates between the native state and an intermediate in the translocation process at estimated forces as low as 1.9 pN. The fluctuation kinetics provide the free energy landscape as a function of force. We show that our stable, ≈15 k(B)T, substrate can be unfolded and translocated with physiological membrane potentials and that selective divalent cation binding may have a profound effect on the translocation kinetics. Nature Publishing Group UK 2020-04-03 /pmc/articles/PMC7125183/ /pubmed/32246057 http://dx.doi.org/10.1038/s42003-020-0841-4 Text en © The Author(s) 2020 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as 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. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.
spellingShingle Article
Rosen, Christian Bech
Bayley, Hagan
Rodriguez-Larrea, David
Free-energy landscapes of membrane co-translocational protein unfolding
title Free-energy landscapes of membrane co-translocational protein unfolding
title_full Free-energy landscapes of membrane co-translocational protein unfolding
title_fullStr Free-energy landscapes of membrane co-translocational protein unfolding
title_full_unstemmed Free-energy landscapes of membrane co-translocational protein unfolding
title_short Free-energy landscapes of membrane co-translocational protein unfolding
title_sort free-energy landscapes of membrane co-translocational protein unfolding
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7125183/
https://www.ncbi.nlm.nih.gov/pubmed/32246057
http://dx.doi.org/10.1038/s42003-020-0841-4
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