Structural Dynamics of Single Metabotropic Glutamate Receptors in Solution

Abstract

Metabotropic glutamate receptors (mGluRs) are multidomain proteins belonging to class C G-protein coupled receptors (GPCR). There are essential in controlling synaptic transmission, and as such are important drug targets for the treatment of several disorders including pain, Parkinson's disease, schizophrenia etc.We recently introduced the use of single molecule FRET combined with Multi-parameter Fluorescence Detection (MFD) and Pulsed Interleaved Excitation (PIE) to investigate the allosteric transitions associated with mGluR activation. We demonstrated that the isolated ligand binding (VFT) domain oscillates between a resting and an active state in a time range of 50-100 µs∗. Here, we extend these investigation to the full length receptor solubilized in detergent and reconstituted in liposomes. Our result confirm the general mechanism observed for the VFT domain, and decipher the role of the transmembrane domain, that slightly slows down the receptor dynamics, while stabilizing its active state solely in the presence of a full agonist.∗Olofsson et al., Nature Comm., 2015