What are the best ways to exchange detergents for membrane protein studies?

Detergents are commonly used in membrane protein studies to solubilize the membrane protein. Unfortunately, the usage of detergents is not without its caveats. Detergents can adversely affect protein confirmation and stability, can complicate purification and/or down-stream studies, and varies in membrane protein compatibility. Luckily, various methods exist to remove detergents from a sample many of which utilize the critical micellar concentration (CMC), charge and aggregation number, these include:

1. Dialysis – Dialysis is one of the practical methods for diluting the detergent concentration and preventing its micellar formation. In this method, the protein-detergent mixture is kept in a semi-permeable membrane and allowed to dialyze against detergent free media for many days to dilute. This method works very well for high CMC detergents with small molecular weights. Avoid this method if using non-ionic detergents with low CMC.
2. Hydrophobic Interaction – Since detergents are amphiphilic by nature (contains both hydrophilic and hydrophobic part) they can interact with hydrophobic resins or beads (insoluble) and be removed by either centrifugation or filtration. This method works well with low CMC detergents.
3. Nickel Column and poly-histidine Tags (His tag) – This method is only suitbale for the proteins having His tag. Since histidine tags have a high binding affinity for nickel, proteins which contain micelles will bind to the nickel and will be removed by washing.

References:

Seddon, A. M., Curnow, P., & Booth, P. J. (2004). Membrane proteins, lipids and detergents: not just a soap opera. Biochimica et Biophysica Acta (BBA)-Biomembranes, 1666(1-2), 105-117.