One of the most challenging problems in biochemical science are studies that involve membranes, including small molecules and proteins which are associated with these cellular structures. Using designed amphipathic helical peptides, termed membrane scaffold proteins (MSPs), the Sligar laboratory has developed a simple and robust system that self-assembles phospholipids into soluble discoidal phospholipid bilayers of defined size (8-16 nm in diameter) termed Nanodiscs. Importantly, the same self-assembly process can be used to directly incorporate a variety of integral membrane proteins and small molecules into Nanodiscs.
The result is a native-like environment that provides stability and full functionality for these integral membrane protein targets. Using MSPs of varying lengths, the size and composition of the Nanodiscs can also control the oligomerization state of incorporated targets.
Additionally, the Sligar laboratory has demonstrated the usefulness of Nanodiscs in a variety of in vivo applications including imaging, delivery of therapeutics and in providing a naturalistic presentation of antigens for control of the immune response.
Applications
All classes of membrane proteins can be effectively solubilized using the Nanodisc technology, including; receptors, for example G-protein coupled receptors (GPCRs) which account for over 50 percent of drug targets; membrane bound enzymes such as the cytochromes P450 and in providing a precisely controlled membrane surface for control of biological processes such as blood coagulation and hemostasis.
Additionally, since the Nanodisc incorporated target can be easily affixed to surfaces without loss of activity, the technology has direct application to uses in high-throughput screening modalities for drug discovery. All assay formats utilized for soluble targets are now applicable to those involving membranes and membrane proteins. Nanodiscs can be generated with natural or synthetic phospholipids, and can be formed pyrrogen free and suitable for in vivo therapeutic delivery allowing numerous applications in the fields of biologicals and small molecule drugs. The availability of lipid or covalent anchoring has also enabled use in the delivery of nucleic acid based therapeutics.