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Cryo-EM structure of the bifunctional secretin complex of Thermus thermophilus
Secretins form multimeric channels across the outer membrane of Gram-negative bacteria that mediate the import or export of substrates and/or extrusion of type IV pili. The secretin complex of Thermus thermophilus is an oligomer of the 757-residue PilQ protein, essential for DNA uptake and pilus ext...
Autores principales: | , , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
eLife Sciences Publications, Ltd
2017
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5745081/ https://www.ncbi.nlm.nih.gov/pubmed/29280731 http://dx.doi.org/10.7554/eLife.30483 |
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author | D'Imprima, Edoardo Salzer, Ralf Bhaskara, Ramachandra M Sánchez, Ricardo Rose, Ilona Kirchner, Lennart Hummer, Gerhard Kühlbrandt, Werner Vonck, Janet Averhoff, Beate |
author_facet | D'Imprima, Edoardo Salzer, Ralf Bhaskara, Ramachandra M Sánchez, Ricardo Rose, Ilona Kirchner, Lennart Hummer, Gerhard Kühlbrandt, Werner Vonck, Janet Averhoff, Beate |
author_sort | D'Imprima, Edoardo |
collection | PubMed |
description | Secretins form multimeric channels across the outer membrane of Gram-negative bacteria that mediate the import or export of substrates and/or extrusion of type IV pili. The secretin complex of Thermus thermophilus is an oligomer of the 757-residue PilQ protein, essential for DNA uptake and pilus extrusion. Here, we present the cryo-EM structure of this bifunctional complex at a resolution of ~7 Å using a new reconstruction protocol. Thirteen protomers form a large periplasmic domain of six stacked rings and a secretin domain in the outer membrane. A homology model of the PilQ protein was fitted into the cryo-EM map. A crown-like structure outside the outer membrane capping the secretin was found not to be part of PilQ. Mutations in the secretin domain disrupted the crown and abolished DNA uptake, suggesting a central role of the crown in natural transformation. |
format | Online Article Text |
id | pubmed-5745081 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2017 |
publisher | eLife Sciences Publications, Ltd |
record_format | MEDLINE/PubMed |
spelling | pubmed-57450812018-01-04 Cryo-EM structure of the bifunctional secretin complex of Thermus thermophilus D'Imprima, Edoardo Salzer, Ralf Bhaskara, Ramachandra M Sánchez, Ricardo Rose, Ilona Kirchner, Lennart Hummer, Gerhard Kühlbrandt, Werner Vonck, Janet Averhoff, Beate eLife Structural Biology and Molecular Biophysics Secretins form multimeric channels across the outer membrane of Gram-negative bacteria that mediate the import or export of substrates and/or extrusion of type IV pili. The secretin complex of Thermus thermophilus is an oligomer of the 757-residue PilQ protein, essential for DNA uptake and pilus extrusion. Here, we present the cryo-EM structure of this bifunctional complex at a resolution of ~7 Å using a new reconstruction protocol. Thirteen protomers form a large periplasmic domain of six stacked rings and a secretin domain in the outer membrane. A homology model of the PilQ protein was fitted into the cryo-EM map. A crown-like structure outside the outer membrane capping the secretin was found not to be part of PilQ. Mutations in the secretin domain disrupted the crown and abolished DNA uptake, suggesting a central role of the crown in natural transformation. eLife Sciences Publications, Ltd 2017-12-27 /pmc/articles/PMC5745081/ /pubmed/29280731 http://dx.doi.org/10.7554/eLife.30483 Text en © 2017, D'Imprima 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 D'Imprima, Edoardo Salzer, Ralf Bhaskara, Ramachandra M Sánchez, Ricardo Rose, Ilona Kirchner, Lennart Hummer, Gerhard Kühlbrandt, Werner Vonck, Janet Averhoff, Beate Cryo-EM structure of the bifunctional secretin complex of Thermus thermophilus |
title | Cryo-EM structure of the bifunctional secretin complex of Thermus thermophilus |
title_full | Cryo-EM structure of the bifunctional secretin complex of Thermus thermophilus |
title_fullStr | Cryo-EM structure of the bifunctional secretin complex of Thermus thermophilus |
title_full_unstemmed | Cryo-EM structure of the bifunctional secretin complex of Thermus thermophilus |
title_short | Cryo-EM structure of the bifunctional secretin complex of Thermus thermophilus |
title_sort | cryo-em structure of the bifunctional secretin complex of thermus thermophilus |
topic | Structural Biology and Molecular Biophysics |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5745081/ https://www.ncbi.nlm.nih.gov/pubmed/29280731 http://dx.doi.org/10.7554/eLife.30483 |
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