The role of NMR spectroscopy in mapping the conformational landscape of GPCRs

•Using multiple labelling strategies, NMR spectroscopy provides insights into the dynamic nature of several class A GPCRs.•Receptors populate a range of states that are in equilibra determined by a complex energy landscape.•General features as well as receptor-specific differences in GPCR allosteric activation are observed.•Agonist binding to a receptor influences the exchange kinetics as well as the population of different states.•Full agonist bound states are observed to be particularly dynamic.