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Structural insight into the role of the Ton complex in energy transduction.

Authors :
Celia H
Noinaj N
Zakharov SD
Bordignon E
Botos I
Santamaria M
Barnard TJ
Cramer WA
Lloubes R
Buchanan SK
Source :
Nature [Nature] 2016 Oct 06; Vol. 538 (7623), pp. 60-65. Date of Electronic Publication: 2016 Sep 21.
Publication Year :
2016

Abstract

In Gram-negative bacteria, outer membrane transporters import nutrients by coupling to an inner membrane protein complex called the Ton complex. The Ton complex consists of TonB, ExbB, and ExbD, and uses the proton motive force at the inner membrane to transduce energy to the outer membrane via TonB. Here, we structurally characterize the Ton complex from Escherichia coli using X-ray crystallography, electron microscopy, double electron-electron resonance (DEER) spectroscopy, and crosslinking. Our results reveal a stoichiometry consisting of a pentamer of ExbB, a dimer of ExbD, and at least one TonB. Electrophysiology studies show that the Ton subcomplex forms pH-sensitive cation-selective channels and provide insight into the mechanism by which it may harness the proton motive force to produce energy.<br />Competing Interests: The authors declare no competing financial interests.

Details

Language :
English
ISSN :
1476-4687
Volume :
538
Issue :
7623
Database :
MEDLINE
Journal :
Nature
Publication Type :
Academic Journal
Accession number :
27654919
Full Text :
https://doi.org/10.1038/nature19757