Elucidating the Structure and Function of Membrane Proteins Through Nanotechnology

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), we have 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. During my seminar I will relay our most recent results in the incorporation of membrane bound enzymes, receptors, transporters and blood coagulation factors into Nanodiscs including the biophysical and biochemical characterization of these nanostructures. In particular, I will describe our use of Nanodiscs to unravel the fundamental mechanistic aspects of human hepatic drug metabolism and steroid hormone biosynthesis, signaling by G-protein coupled receptors and the use of these nanoscale bilayers in the areas of drug delivery and high throughput screening of therapeutics. Our research is supported by the National Institutes of Health grants GM33775 and GM31756.