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 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.

Download full text files

Export metadata

Metadaten
Author:Edoardo D'ImprimaORCiDGND, Ralf SalzerORCiDGND, Ramachandra M. BhaskaraORCiD, Ricardo Sánchez, Ilona Rose, Lennart Kirchner, Gerhard HummerORCiD, Werner KühlbrandtORCiDGND, Janet VonckORCiD, Beate AverhoffORCiD
URN:urn:nbn:de:hebis:30:3-455752
DOI:https://doi.org/10.7554/eLife.30483.001
ISSN:2050-084X
Pubmed Id:https://pubmed.ncbi.nlm.nih.gov/29280731
Parent Title (English):eLife
Publisher:eLife Sciences Publications
Place of publication:Cambridge
Contributor(s):Wesley I. Sundquist
Document Type:Article
Language:English
Year of Completion:2017
Date of first Publication:2017/12/27
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2018/01/25
Tag:Biophysics and structural biology; Cryo-electron microscopy; Natural transformation; Pilus; Research article; Secretin; Thermus thermophilus
Volume:6
Issue:e30483
Page Number:23
First Page:1
Last Page:23
Note:
Copyright D’Imprima et al. This article is distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use and redistribution provided that the original author and source are credited.
HeBIS-PPN:425781046
Institutes:Physik / Physik
Biowissenschaften / Biowissenschaften
Angeschlossene und kooperierende Institutionen / MPI für Biophysik
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 57 Biowissenschaften; Biologie / 570 Biowissenschaften; Biologie
Sammlungen:Universitätspublikationen
Licence (German):License LogoCreative Commons - Namensnennung 4.0