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The conformations and basal conformational dynamics of translocation factor SecDF vary with translocon SecYEG interaction
The general secretory, or Sec, system is a primary protein export pathway from the cytosol of Escherichia coli and all eubacteria. Integral membrane protein complex SecDF is a translocation factor that enhances polypeptide secretion, which is driven by the Sec translocase, consisting of translocon S...
Autores principales: | , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
American Society for Biochemistry and Molecular Biology
2022
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9508474/ https://www.ncbi.nlm.nih.gov/pubmed/36007614 http://dx.doi.org/10.1016/j.jbc.2022.102412 |
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author | Weaver, D.R. Amin, D.N. King, G.M. |
author_facet | Weaver, D.R. Amin, D.N. King, G.M. |
author_sort | Weaver, D.R. |
collection | PubMed |
description | The general secretory, or Sec, system is a primary protein export pathway from the cytosol of Escherichia coli and all eubacteria. Integral membrane protein complex SecDF is a translocation factor that enhances polypeptide secretion, which is driven by the Sec translocase, consisting of translocon SecYEG and ATPase SecA. SecDF is thought to utilize a proton gradient to effectively pull precursor proteins from the cytoplasm into the periplasm. Working models have been developed to describe the structure and function of SecDF, but important mechanistic questions remain unanswered. Atomic force microscopy (AFM) is a powerful technique for studying the dynamics of single-molecule systems including membrane proteins in near-native conditions. The sharp tip of the AFM provides direct access to membrane-external protein conformations. Here, we acquired AFM images and kymographs (∼100 ms resolution) to visualize SecDF protrusions in near-native supported lipid bilayers and compared the experimental data to simulated AFM images based on static structures. When studied in isolation, SecDF exhibited a stable and compact conformation close to the lipid bilayer surface, indicative of a resting state. Interestingly, upon SecYEG introduction, we observed changes in both SecDF conformation and conformational dynamics. The population of periplasmic protrusions corresponding to an intermediate form of SecDF, which is thought to be active in precursor protein handling, increased more than ninefold. In conjunction, our dynamics measurements revealed an enhancement in the transition rate between distinct SecDF conformations when the translocon was present. Together, this work provides a novel vista of basal-level SecDF conformational dynamics in near-native conditions. |
format | Online Article Text |
id | pubmed-9508474 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2022 |
publisher | American Society for Biochemistry and Molecular Biology |
record_format | MEDLINE/PubMed |
spelling | pubmed-95084742022-09-30 The conformations and basal conformational dynamics of translocation factor SecDF vary with translocon SecYEG interaction Weaver, D.R. Amin, D.N. King, G.M. J Biol Chem Research Article The general secretory, or Sec, system is a primary protein export pathway from the cytosol of Escherichia coli and all eubacteria. Integral membrane protein complex SecDF is a translocation factor that enhances polypeptide secretion, which is driven by the Sec translocase, consisting of translocon SecYEG and ATPase SecA. SecDF is thought to utilize a proton gradient to effectively pull precursor proteins from the cytoplasm into the periplasm. Working models have been developed to describe the structure and function of SecDF, but important mechanistic questions remain unanswered. Atomic force microscopy (AFM) is a powerful technique for studying the dynamics of single-molecule systems including membrane proteins in near-native conditions. The sharp tip of the AFM provides direct access to membrane-external protein conformations. Here, we acquired AFM images and kymographs (∼100 ms resolution) to visualize SecDF protrusions in near-native supported lipid bilayers and compared the experimental data to simulated AFM images based on static structures. When studied in isolation, SecDF exhibited a stable and compact conformation close to the lipid bilayer surface, indicative of a resting state. Interestingly, upon SecYEG introduction, we observed changes in both SecDF conformation and conformational dynamics. The population of periplasmic protrusions corresponding to an intermediate form of SecDF, which is thought to be active in precursor protein handling, increased more than ninefold. In conjunction, our dynamics measurements revealed an enhancement in the transition rate between distinct SecDF conformations when the translocon was present. Together, this work provides a novel vista of basal-level SecDF conformational dynamics in near-native conditions. American Society for Biochemistry and Molecular Biology 2022-08-22 /pmc/articles/PMC9508474/ /pubmed/36007614 http://dx.doi.org/10.1016/j.jbc.2022.102412 Text en © 2022 The Authors https://creativecommons.org/licenses/by/4.0/This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Research Article Weaver, D.R. Amin, D.N. King, G.M. The conformations and basal conformational dynamics of translocation factor SecDF vary with translocon SecYEG interaction |
title | The conformations and basal conformational dynamics of translocation factor SecDF vary with translocon SecYEG interaction |
title_full | The conformations and basal conformational dynamics of translocation factor SecDF vary with translocon SecYEG interaction |
title_fullStr | The conformations and basal conformational dynamics of translocation factor SecDF vary with translocon SecYEG interaction |
title_full_unstemmed | The conformations and basal conformational dynamics of translocation factor SecDF vary with translocon SecYEG interaction |
title_short | The conformations and basal conformational dynamics of translocation factor SecDF vary with translocon SecYEG interaction |
title_sort | conformations and basal conformational dynamics of translocation factor secdf vary with translocon secyeg interaction |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9508474/ https://www.ncbi.nlm.nih.gov/pubmed/36007614 http://dx.doi.org/10.1016/j.jbc.2022.102412 |
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