HAL will be down for maintenance from Friday, June 10 at 4pm through Monday, June 13 at 9am. More information
Skip to Main content Skip to Navigation
Journal articles

Mapping the Interactions between Escherichia coli Tol Subunits

Abstract : The TolQRA proteins of Escherichia coli form an inner membrane complex involved in the maintenance of the outer membrane stability and in the late stages of cell division. The TolQR complex uses the proton motive force to regulate TolA conformation and its interaction with the outer membrane Pal lipoprotein. It has been proposed that an ion channel forms at the TolQR transmembrane helix (TMH) interface. This complex assembles with a minimal TolQ:TolR ratio of 4–6:2 and therefore involves 14–20 TMHs. To define the organization of the transmembrane helices in the membrane within the TolQR complex, we initiated a cysteine scanning study. In this study, we report results for the systematic replacement of each residue of the TolR TMH. Phenotypic analyses first showed that most of the mutants are functional. Three mutants, TolR L22C, D23C, and V24C, were shown to affect TolQR functioning. Disulfide bond complex formation further showed that two TolR anchors are close enough to interact. Two substitutions, L22C and V24C, form high level of dimers, suggesting that the TolR helix rotates as molecular gears between these two positions and that disulfide bond formation between these residues blocked the rotary motion. Mutations of critical residues located within the TolQ TMH2 and TMH3 and the TolR TMH and proposed to form the ion pathway prevent rotation between these two residues. TolR anchors may form molecular gears that oscillate in response to proton motive force to regulate channel activity.
Document type :
Journal articles
Complete list of metadata

Contributor : Eric Cascales Connect in order to contact the contributor
Submitted on : Tuesday, September 14, 2021 - 3:30:04 PM
Last modification on : Wednesday, October 27, 2021 - 10:00:11 AM
Long-term archiving on: : Wednesday, December 15, 2021 - 6:46:28 PM


Publisher files allowed on an open archive


Distributed under a Creative Commons Attribution 4.0 International License




Xiang Y.-Z. Zhang, Emilie Goemaere, Rémi Thomé, Marthe Gavioli, E. Cascales, et al.. Mapping the Interactions between Escherichia coli Tol Subunits. Journal of Biological Chemistry, American Society for Biochemistry and Molecular Biology, 2009, 284 (7), pp.4275-4282. ⟨10.1074/jbc.M805257200⟩. ⟨hal-03274816⟩



Record views


Files downloads