As one of the leading protein suppliers, Alpha Lifetech Inc. is always trying to provide high-quality protein services to scientists. By using polymers, the final product of recombinant membrane protein has been fixed by amphipathic polymer for subsequent study of structure and function.

Membrane Protein Production in Polymers

Recombinant membrane protein is often produced in a precipitated form in a cell-free expression system that yields soluble proteins by adding detergents or amphipathic polymer. Compared to the detergents, amphipathic polymer can't induce the dissociation of the subunits, as a result, keeping an activated form of the membrane protein in high possibility.

The most widely use of polymer materials today are poly (styrene-co-maleic acid) lipid particles (SMALPs) and amphipols (A8-35).

Poly (styrene-co-maleic acid) lipid particles (SMALPs) consist of alternating hydrophilic and hydrophobic moieties. At neutral or alkaline pH, the polymer assembles into a disc-like structure, encapsulating the membrane protein in a form amenable to being soluble. At acidic pH, the polymer disassociates from the particle, leaving the membrane protein behind.

Fig. 1 GPCR (Multiple colors) Stabilized by Styrene-co-maleic Acid Lipid (Grey) Particles

Amphipols (APs) are different kinds of surfactants by which membrane proteins can be handled in aqueous solutions as complexes without detergents. APs are amphiphilic polymers that bind to the transmembrane surface of the protein in a noncovalent and membrane proteins complexed by APs are in their native state, stable, and they remain water-soluble in the absence of detergent or free Aps.

Fig. 2 the Schematic of Amphipols-binding (grey) Membrane Protein (pink).