Method to measure strong protein-protein interactions in lipid bilayers using a steric trap.

Measuring high affinity protein-protein interactions in membranes is extremely challenging because there are limitations to how far the interacting components can be diluted in bilayers. Here we show that a steric trap can be employed for stable membrane interactions. We couple dissociation to a competitive binding event so that dissociation can be driven by increasing the affinity or concentration of the competitor.

Protein unfolding with a steric trap.

The study of protein folding requires a method to drive unfolding, which is typically accomplished by altering solution conditions to favor the denatured state. This has the undesirable consequence that the molecular forces responsible for configuring the polypeptide chain are also changed. It would therefore be useful to develop methods that can drive unfolding without the need for destabilizing solvent conditions.

G-protein-coupled receptor structures were not built in a day.

Among the most exciting recent developments in structural biology is the structure determination of G-protein-coupled receptors (GPCRs), which comprise the largest class of membrane proteins in mammalian cells and have enormous importance for disease and drug development. The GPCR structures are perhaps the most visible examples of a nascent revolution in membrane protein structure determination. Like other major milestones in science, however, such as the sequencing of the human genome, these achievements were built on a hidden foundation of technological developments.