Membrane proteins are ubiquitous in biology, yet it is challenging to maintain a physiologically relevant environment during experiments. We construct well-controlled synthetic membrane-protein systems that mimic physiological environments without the complexity of living organisms.
TEM images (top) of nanodiscs containing LHCIIs, where the average number per nanodisc increases discretely from one (left) to four (right), with cartoon depictions of the LHCII-containing nanodiscs (bottom).
We employ discoidal lipid bilayers, known as nanodiscs, in a range of lipid compositions and diameters to study light-harvesting complexes and transmembrane receptors. Nanodiscs consist of a lipid bilayer encircled by an amphipathic belting protein, which can embed membrane proteins to provide a near-native environment and low membrane curvature. The lipid composition can be varied to investigate the nature and role of protein-lipid interactions and membrane properties. The area can be controlled with the identity of the belting protein to accommodate multiple membrane proteins per disc, providing a platform to explore protein-protein interactions.
We also employ proteoliposomes, where membrane proteins are embedded in large, spherical liposomes with high membrane curvature. In these systems, the protein content can be varied to study higher order protein interactions.