Detergent Purification of Membrane Proteins

Detergents contain hydrophilic head groups and hydrophobic tails, which allow them to form spherical micelles; therefore, they are widely used to purify membrane proteins.

There are three types of detergents – ionic, non-ionic, and zwitterionic.

Ionic detergents such as sodium dodecyl sulfate have charged head groups, whereas non-ionic detergents such as Triton X-100 are uncharged.

Zwitterionic detergents like CHAPS have headgroups with both positive and negative charges.

Non-ionic and zwitterionic detergents are most commonly used for protein purification as they allow the protein to retain its functional form. In contrast, ionic detergents can denature the target proteins.

Integral membrane proteins are purified in three distinct stages. First, the detergent micelle interacts with the outer bilayer of the membrane.

Next, the membrane is solubilized, with the formation of lipid-detergent and protein-detergent complexes.

Once the detergents are removed, the protein can be purified using techniques such as affinity chromatography.