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HDX-MS reveals nucleotide-dependent, anti-correlated opening and closure of SecA and SecY channels of the bacterial translocon

The bacterial Sec translocon is a multi-protein complex responsible for translocating diverse proteins across the plasma membrane. For post-translational protein translocation, the Sec-channel – SecYEG – associates with the motor protein SecA to mediate the ATP-dependent transport of pre-proteins ac...

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Autores principales: Ahdash, Zainab, Pyle, Euan, Allen, William John, Corey, Robin A, Collinson, Ian, Politis, Argyris
Formato: Online Artículo Texto
Lenguaje:English
Publicado: eLife Sciences Publications, Ltd 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6639072/
https://www.ncbi.nlm.nih.gov/pubmed/31290743
http://dx.doi.org/10.7554/eLife.47402
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author Ahdash, Zainab
Pyle, Euan
Allen, William John
Corey, Robin A
Collinson, Ian
Politis, Argyris
author_facet Ahdash, Zainab
Pyle, Euan
Allen, William John
Corey, Robin A
Collinson, Ian
Politis, Argyris
author_sort Ahdash, Zainab
collection PubMed
description The bacterial Sec translocon is a multi-protein complex responsible for translocating diverse proteins across the plasma membrane. For post-translational protein translocation, the Sec-channel – SecYEG – associates with the motor protein SecA to mediate the ATP-dependent transport of pre-proteins across the membrane. Previously, a diffusional-based Brownian ratchet mechanism for protein secretion has been proposed; the structural dynamics required to facilitate this mechanism remain unknown. Here, we employ hydrogen-deuterium exchange mass spectrometry (HDX-MS) to reveal striking nucleotide-dependent conformational changes in the Sec protein-channel from Escherichia coli. In addition to the ATP-dependent opening of SecY, reported previously, we observe a counteracting, and ATP-dependent, constriction of SecA around the pre-protein. ATP binding causes SecY to open and SecA to close; while, ADP produced by hydrolysis, has the opposite effect. This alternating behaviour could help impose the directionality of the Brownian ratchet for protein transport through the Sec machinery.
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spelling pubmed-66390722019-07-19 HDX-MS reveals nucleotide-dependent, anti-correlated opening and closure of SecA and SecY channels of the bacterial translocon Ahdash, Zainab Pyle, Euan Allen, William John Corey, Robin A Collinson, Ian Politis, Argyris eLife Structural Biology and Molecular Biophysics The bacterial Sec translocon is a multi-protein complex responsible for translocating diverse proteins across the plasma membrane. For post-translational protein translocation, the Sec-channel – SecYEG – associates with the motor protein SecA to mediate the ATP-dependent transport of pre-proteins across the membrane. Previously, a diffusional-based Brownian ratchet mechanism for protein secretion has been proposed; the structural dynamics required to facilitate this mechanism remain unknown. Here, we employ hydrogen-deuterium exchange mass spectrometry (HDX-MS) to reveal striking nucleotide-dependent conformational changes in the Sec protein-channel from Escherichia coli. In addition to the ATP-dependent opening of SecY, reported previously, we observe a counteracting, and ATP-dependent, constriction of SecA around the pre-protein. ATP binding causes SecY to open and SecA to close; while, ADP produced by hydrolysis, has the opposite effect. This alternating behaviour could help impose the directionality of the Brownian ratchet for protein transport through the Sec machinery. eLife Sciences Publications, Ltd 2019-07-10 /pmc/articles/PMC6639072/ /pubmed/31290743 http://dx.doi.org/10.7554/eLife.47402 Text en © 2019, Ahdash et al http://creativecommons.org/licenses/by/4.0/ http://creativecommons.org/licenses/by/4.0/This article is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use and redistribution provided that the original author and source are credited.
spellingShingle Structural Biology and Molecular Biophysics
Ahdash, Zainab
Pyle, Euan
Allen, William John
Corey, Robin A
Collinson, Ian
Politis, Argyris
HDX-MS reveals nucleotide-dependent, anti-correlated opening and closure of SecA and SecY channels of the bacterial translocon
title HDX-MS reveals nucleotide-dependent, anti-correlated opening and closure of SecA and SecY channels of the bacterial translocon
title_full HDX-MS reveals nucleotide-dependent, anti-correlated opening and closure of SecA and SecY channels of the bacterial translocon
title_fullStr HDX-MS reveals nucleotide-dependent, anti-correlated opening and closure of SecA and SecY channels of the bacterial translocon
title_full_unstemmed HDX-MS reveals nucleotide-dependent, anti-correlated opening and closure of SecA and SecY channels of the bacterial translocon
title_short HDX-MS reveals nucleotide-dependent, anti-correlated opening and closure of SecA and SecY channels of the bacterial translocon
title_sort hdx-ms reveals nucleotide-dependent, anti-correlated opening and closure of seca and secy channels of the bacterial translocon
topic Structural Biology and Molecular Biophysics
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6639072/
https://www.ncbi.nlm.nih.gov/pubmed/31290743
http://dx.doi.org/10.7554/eLife.47402
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