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Structure of the substrate-engaged SecA-SecY protein translocation machine

The Sec61/SecY channel allows the translocation of many proteins across the eukaryotic endoplasmic reticulum membrane or the prokaryotic plasma membrane. In bacteria, most secretory proteins are transported post-translationally through the SecY channel by the SecA ATPase. How a polypeptide is moved...

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Autores principales: Ma, Chengying, Wu, Xiaofei, Sun, Dongjie, Park, Eunyong, Catipovic, Marco A., Rapoport, Tom A., Gao, Ning, Li, Long
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group UK 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6599042/
https://www.ncbi.nlm.nih.gov/pubmed/31253804
http://dx.doi.org/10.1038/s41467-019-10918-2
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author Ma, Chengying
Wu, Xiaofei
Sun, Dongjie
Park, Eunyong
Catipovic, Marco A.
Rapoport, Tom A.
Gao, Ning
Li, Long
author_facet Ma, Chengying
Wu, Xiaofei
Sun, Dongjie
Park, Eunyong
Catipovic, Marco A.
Rapoport, Tom A.
Gao, Ning
Li, Long
author_sort Ma, Chengying
collection PubMed
description The Sec61/SecY channel allows the translocation of many proteins across the eukaryotic endoplasmic reticulum membrane or the prokaryotic plasma membrane. In bacteria, most secretory proteins are transported post-translationally through the SecY channel by the SecA ATPase. How a polypeptide is moved through the SecA-SecY complex is poorly understood, as structural information is lacking. Here, we report an electron cryo-microscopy (cryo-EM) structure of a translocating SecA-SecY complex in a lipid environment. The translocating polypeptide chain can be traced through both SecA and SecY. In the captured transition state of ATP hydrolysis, SecA’s two-helix finger is close to the polypeptide, while SecA’s clamp interacts with the polypeptide in a sequence-independent manner by inducing a short β-strand. Taking into account previous biochemical and biophysical data, our structure is consistent with a model in which the two-helix finger and clamp cooperate during the ATPase cycle to move a polypeptide through the channel.
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spelling pubmed-65990422019-07-01 Structure of the substrate-engaged SecA-SecY protein translocation machine Ma, Chengying Wu, Xiaofei Sun, Dongjie Park, Eunyong Catipovic, Marco A. Rapoport, Tom A. Gao, Ning Li, Long Nat Commun Article The Sec61/SecY channel allows the translocation of many proteins across the eukaryotic endoplasmic reticulum membrane or the prokaryotic plasma membrane. In bacteria, most secretory proteins are transported post-translationally through the SecY channel by the SecA ATPase. How a polypeptide is moved through the SecA-SecY complex is poorly understood, as structural information is lacking. Here, we report an electron cryo-microscopy (cryo-EM) structure of a translocating SecA-SecY complex in a lipid environment. The translocating polypeptide chain can be traced through both SecA and SecY. In the captured transition state of ATP hydrolysis, SecA’s two-helix finger is close to the polypeptide, while SecA’s clamp interacts with the polypeptide in a sequence-independent manner by inducing a short β-strand. Taking into account previous biochemical and biophysical data, our structure is consistent with a model in which the two-helix finger and clamp cooperate during the ATPase cycle to move a polypeptide through the channel. Nature Publishing Group UK 2019-06-28 /pmc/articles/PMC6599042/ /pubmed/31253804 http://dx.doi.org/10.1038/s41467-019-10918-2 Text en © The Author(s) 2019 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
Ma, Chengying
Wu, Xiaofei
Sun, Dongjie
Park, Eunyong
Catipovic, Marco A.
Rapoport, Tom A.
Gao, Ning
Li, Long
Structure of the substrate-engaged SecA-SecY protein translocation machine
title Structure of the substrate-engaged SecA-SecY protein translocation machine
title_full Structure of the substrate-engaged SecA-SecY protein translocation machine
title_fullStr Structure of the substrate-engaged SecA-SecY protein translocation machine
title_full_unstemmed Structure of the substrate-engaged SecA-SecY protein translocation machine
title_short Structure of the substrate-engaged SecA-SecY protein translocation machine
title_sort structure of the substrate-engaged seca-secy protein translocation machine
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6599042/
https://www.ncbi.nlm.nih.gov/pubmed/31253804
http://dx.doi.org/10.1038/s41467-019-10918-2
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