Figure 1.

Schematic representation of membrane protein purification using the traditional detergent-based approach and the detergent-free polymer-based approach. The steps include protein expression, cell lysis, and purification. Unlike the detergent-based approach, in the detergent-free polymer-based method, a synthetic polymer is added to cell lysates to dissolve them to form polymer–membrane complexes from which nanodiscs containing the desired protein are isolated. In the nanodisc-membrane, the lipids are orderly packed, facing the hydrophobic tails inward and the hydrophilic head groups exposed to an aqueous environment.