Conformational diversity and contraction of the denatured state ensemble of a helical membrane protein

Defining the denatured state ensemble (DSE) of both soluble and membrane proteins is essential to understanding protein folding, thermodynamics, chaperone action, degradation, translocation, and cell signaling. While many studies have focused on water-soluble proteins, the DSE of membrane proteins is less well characterized. We reconstituted the DSE of a helical-bundle membrane protein GlpG in native-like E. coli lipid bilayers using our steric trapping method, which couples spontaneous denaturation of doubly biotinylated GlpG to the binding of two bulky streptavidin molecules.