August 3rd, 2016.
Here we report the measurement of the dimerization free energy of ClC-ec1 in lipid bilayers, along with a new approach for measuring monomer vs. dimer stoichiometry across a wide range of protein densities in the membrane, using a single-molecule fluorescence photobleaching approach to describe the proximity of subunits in the equilibrated membranes. These results show that the ClC homodimer is one of the strongest membrane protein dimers measured so far. Furthermore, we describe how the addition of bulky tryptophans destabilize the free energy. This introduces ClC as a new type of model system for dissecting the physical driving forces underlying membrane protein folding and association in membranes.