Liposome Technology Platform

The traditional method of extracting membrane proteins is to use a detergent to separate the target membrane protein from all other components. Various reagents can disrupt the membrane, but the membrane that these reagents disrupt also removes the membrane surrounding the protein, which may affect the folding as well as the activity of the protein.

A single detergent does not mimic well the phospholipid bilayer environment in which membrane proteins reside. The choice of detergent is also time-consuming and lacks a uniform solution, which limits the efficiency of studying membrane proteins.

New membrane protein extraction methods are being developed to extract and purify proteins from natural membranes and transfer these discs into membranes composed of lipids. Using amphiphilic copolymers, the target membrane proteins are extracted and separated from natural lipids without the use of detergents.

Styrene-maleic acid (SMA) copolymers are increasingly used in membrane protein extraction and purification.

• SMA is inserted into the membrane and assembled into small disks surrounded by polymers called SMA lipid particles (SMALPs).
• The target SMALPs are obtained by affinity chromatography purification.
• Natural nanodiscs containing the target proteins are mixed with these liposomes, and the samples are then subjected to the displacement of membrane proteins into the liposome by extrusion or sonication.
• Finally, the samples are analyzed by SDS-PAGE and concentration measurements are performed.

Figure 1. Schematic outline of the method for extracting protein with native membranes from SMA polymer (Smirnova, I. A. et al, 2018).

Although SMALPs do not affect proteins compared to detergents, they have limitations, most notably sensitivity to low pH and divalent cations. It has recently been shown that di-isobutylene maleic acid (DIBMA) copolymers can also directly solubilize membranes to form DIBMA lipid particles (DIBMALPs) and that this polymer overcomes some of the limitations of SMA.

Creative Biomart has state-of-the-art equipment and a specialized team in liposome preparation and membrane protein extraction. We provide a liposome technology platform that offers new technological means for membrane protein extraction methods. Membrane proteins prepared through liposomes do not require the use of detergents, can stabilize their structure, and remain active.

Creative Biomart not only provides membrane protein expression and purification services, we will design and select the appropriate means of membrane protein preparation according to your needs. If you have any questions, please feel free to contact us.

Reference:

1. Smirnova, I. A., Ädelroth, P., & Brzezinski, P. (2018). Extraction and liposome reconstitution of membrane proteins with their native lipids without the use of detergents. Scientific reports, 8(1), 14950.