Alternative and cost-effective adsorbent for detergent removal in membrane protein solubilization

Membrane proteins (MPs) are essential for various cellular functions and therefore critical targets for the drug industry. However structural and functional studies of MPs are challenging due to the difficulty and cost of solubilization and purification. Effective solubilization typically requires the incorporation of MPs into detergent micelles. Despite that this is a common practice, it has the potential to destabilize MPs. Alternatively, detergent-free systems have emerged, and reconstitution of MPs in Amphipol is one of the common methods. Polystyrene beads, typically Bio-Beads, are generally used for this purpose but the cost is a significant limitation. To reduce costs, we investigated an alternative to Bio-Beads and evaluated the effectiveness of polydivinylbenzene PAD600 beads. To accomplish this, the membrane protein FtsH, solubilized in either DDM or LMNG, was exchanged with varying concentrations of Amphipol, and detergents were removed by PAD600 beads. The results demonstrate that PAD600 beads are effective for detergent removal when the mass ratio of the MP:Amphipol is increased up to 1:10. The usage of PAD600 beads supports cost-effective biochemical applications for membrane protein isolation and purification studies.