Two-Dimensional NMR Spectroscopy of the G Protein-Coupled Receptor A 2A AR in Lipid Nanodiscs

• Published in: Molecules (Basel, Switzerland) Vol. 28; no. 14
• Main Authors: Guo, Canyong, Yang, Lingyun, Liu, Zhijun, Liu, Dongsheng, Wüthrich, Kurt
• Format: Journal Article
• Language: English
• Published: Switzerland 14.07.2023
• Subjects: A2A adenosine receptor; lipid nanodiscs; GPCR; solution NMR
• ISSN: 1420-3049

Eight hundred and twenty-six human G protein-coupled receptors (GPCRs) mediate the actions of two-thirds of the human hormones and neurotransmitters and over one-third of clinically used drugs. Studying the structure and dynamics of human GPCRs in lipid bilayer environments resembling the native cell membrane milieu is of great interest as a basis for understanding structure-function relationships and thus benefits continued drug development. Here, we incorporate the human A adenosine receptor (A AR) into lipid nanodiscs, which represent a detergent-free environment for structural studies using nuclear magnetic resonance (NMR) in solution. The [ N, H]-TROSY correlation spectra confirmed that the complex of [u- N, ~70% H]-A AR with an inverse agonist adopts its global fold in lipid nanodiscs in solution at physiological temperature. The global assessment led to two observations of practical interest. First, A AR in nanodiscs can be stored for at least one month at 4 °C in an aqueous solvent. Second, LMNG/CHS micelles are a very close mimic of the environment of A AR in nanodiscs. The NMR signal of five individually assigned tryptophan indole N- H moieties located in different regions of the receptor structure further enabled a detailed assessment of the impact of nanodiscs and LMNG/CHS micelles on the local structure and dynamics of A AR. As expected, the largest effects were observed near the lipid-water interface along the intra- and extracellular surfaces, indicating possible roles of tryptophan side chains in stabilizing GPCRs in lipid bilayer membranes.