19F-NMR studies of the impact of different detergents and nanodiscs on the A2A adenosine receptor

Solution NMR goes big: Atomic resolution studies of protein components of molecular machines and phase-separated condensates

The tools of structural biology have undergone remarkable advances in the past decade. These include new computational and experimental approaches that have enabled studies at a level of detail - and ease - that were not previously possible. Yet, significant deficiencies in our understanding of biomolecular function remain and new challenges must be overcome to go beyond static pictures towards a description of function in terms of structural dynamics. Solution Nuclear Magnetic Resonance (NMR) spectroscopy has emerged as a powerful technique for atomic resolution studies of the dynamics of a wide range of biomolecules, including molecular machines and the components of phase-separated condensates. Here we highlight some of the very recent advances in these areas that have been driven by NMR.

Membrane mimetic-dependence of GPCR energy landscapes

We leveraged variable-temperature 19F-NMR spectroscopy to compare the conformational equilibria of the human A2A adenosine receptor (A2AAR), a class A G protein-coupled receptor (GPCR), across a range of temperatures ranging from lower temperatures typically employed in 19F-NMR experiments to physiological temperature. A2AAR complexes with partial agonists and full agonists showed large increases in the population of a fully active conformation with increasing temperature. NMR data measured at physiological temperature were more in line with functional data. This was pronounced for complexes with partial agonists, where the population of active A2AAR was nearly undetectable at lower temperature but became evident at physiological temperature. Temperature-dependent behavior of complexes with either full or partial agonists exhibited a pronounced sensitivity to the specific membrane mimetic employed. Cellular signaling experiments correlated with the temperature-dependent conformational equilibria of A2AAR in lipid nanodiscs but not in some detergents, underscoring the importance of the membrane environment in studies of GPCR function.