Membrane mimetic environments alter the conformation of the outer membrane protein Btu

The site-directed spin labeling (SDSL) and EPR spectroscopy is used to show that the conformation of the N-terminal energy-coupling motif of BtuB in micelles or bicelles differs from its structure in a bilayer phase. It is found that relatively mild detergents such as OG and DM can alter the conformation of membrane proteins, and that detergents are not necessarily a substitute for a membrane environment.