Techniques: plasmon-waveguide resonance (PWR) spectroscopy as a tool to study ligand-GPCR interactions.

Plasmon-waveguide resonance (PWR) spectroscopy can be applied to integral membrane proteins incorporated into a supported lipid bilayer without the need for labeling. With high sensitivity and wide dynamic range, this technique can be used to characterize the kinetics and thermodynamics of conformational events associated with the binding of ligands to G-protein-coupled receptors (GPCRs), and to directly examine the interactions of GPCRs with G proteins and other downstream effectors in signal transduction. This allows an easy distinction to be made between agonists, antagonists and inverse agonists, and provides a powerful new tool for studying membrane signaling and for drug development.