Integral membrane proteins, in particular receptors, regulate numerous physiological functions. The primary difficulty presented by their studyin vitrois to obtain them in sufficient amounts in a functional state.Escherichia coliis a host of choice for producing recombinant proteins for structural studies. However, insertion of G-protein coupled receptors into its plasma membrane usually results in bacterial death. An alternative approach consists of targeting recombinant receptors to inclusion bodies, where they accumulate without affecting bacterial growth, and then fold themin vitro.We describe here a general approach that consists of accumulating the receptor in bacterial inclusion bodies, then purifying it under denaturing conditions. A simple assay is then described to screen for refolding conditions of the protein.
