The dimerization equilibrium of a ClC Cl-/H+ antiporter in lipid bilayers
- University of Iowa, United States
- Brandeis University, United States
Abstract
Interactions between membrane protein interfaces in lipid bilayers play an important role in membrane protein folding but quantification of the strength of these interactions has been challenging. Studying dimerization of ClC-type transporters offers a new approach to the problem, as individual subunits adopt a stable and functionally verifiable fold that constrains the system to two states - monomer or dimer. Here, we use single-molecule photobleaching analysis to measure the probability of ClC-ec1 subunit capture into liposomes during extrusion of large, multilamellar membranes. The capture statistics describe a monomer to dimer transition that is dependent on the subunit/lipid mole fraction density and follows an equilibrium dimerization isotherm. This allows for the measurement of the free energy of ClC-ec1 dimerization in lipid bilayers, revealing that it is one of the strongest membrane protein complexes measured so far, and introduces it as new type of dimerization model to investigate the physical forces that drive membrane protein association in membranes.
Article and author information
Author details
Janice L Robertson
Funding
National Institutes of Health (R00GM101016)
- Venkatramanan Krishnamani
- Kacey Mersch
- Janice L Robertson
Roy J. Carver Charitable Trust (Early Investigator Award)
- Rahul Chadda
- Marley Brimberry
- Ankita Chadda
- Janice L Robertson
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Reviewing Editor
- Olga Boudker, Weill Cornell Medical College, United States
Version history
- Received: May 1, 2016
- Accepted: July 29, 2016
- Accepted Manuscript published: August 3, 2016 (version 1)
- Version of Record published: September 2, 2016 (version 2)
Copyright
© 2016, Chadda et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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The dimerization equilibrium of a ClC Cl-/H+ antiporter in lipid bilayers
eLife 5:e17438.
https://doi.org/10.7554/eLife.17438
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