Detergent-Free Functionalization of Hybrid Vesicles with Membrane Proteins Using SMALPs

Hybrid vesicles (HVs) that consist of mixtures of block copolymers and lipids are robust biomimetics of liposomes, providing a valuable building block in bionanotechnology, catalysis, and synthetic biology. However, functionalization of HVs with membrane proteins remains laborious and expensive, creating a significant current challenge in the field. Here, using a new approach of extraction with styrene-maleic acid (SMA), we show that a membrane protein (cytochrome bo(3)) directly transfers into HVs with an efficiency of 73.9 +/- 13.5% without the requirement of detergent, long incubation times, or mechanical disruption. Direct transfer of membrane proteins using this approach was not possible into liposomes, suggesting that HVs are more amenable than liposomes to membrane protein incorporation from a SMA lipid particle system. Finally, we show that this transfer method is not limited to cytochrome bo(3) and can also be performed with complex membrane protein mixtures.

Automated summary

In this study, we demonstrate a new approach of extracting membrane proteins using styrene-maleic acid (SMA) that allows for direct transfer of cytochrome bo(3) into hybrid vesicles (HVs). This method is efficient, avoiding the need for detergent, long incubation times, or mechanical disruption. HVs are shown to be more suitable than liposomes for membrane protein incorporation from SMA lipid particles. Furthermore, this transfer method is not limited to a single membrane protein and can be used with complex membrane protein mixtures.