Mapping G Protein Coupled Receptor Interactions using Carbene Footprinting

The project will focus on the use of photoactivatable diazirine probes and mass spectrometry to footprint G-protein coupled receptors (GPCRs) in order to map interactions and identify conformational changes. GPCRs are a large group of membrane-bound receptors which are of major importance for signal transduction in eukaryotic organisms. They are responsible for the detection of extracellular ligands and promoting down-stream signal transduction. As their name suggests, they are found in association with G protein assemblies, which carry the signal to the interior of cell. GCPRs possess a conserved 7-pass transmembrane helical structure. Upon ligand binding, a conformational shift is induced. This causes disassembly of the associated G protein complex and propagation of the signal through either the cAMP or phosphatidylinositol pathways. Recently, we have developed a probe for efficient photochemical footprinting of membrane proteins. Mass spectrometry, a powerful analytical technique, is used to identify the locations of probe attachment, and hence surface accessible regions. This approach will be used map GPCR interactions with small molecule ligands and G protein. Candidates should hold, or expect to hold, a first or upper second class degree in chemistry or biochemistry and have a strong interest in biological mass spectrometry.