Backbone 1H, 13C, and 15N resonance assignments of the ligand binding domain of the human wildtype glucocorticoid receptor and the F602S mutant variant.

The glucocorticoid receptor (GR) is a nuclear hormone receptor that regulates key genes controlling development, metabolism, and the immune response. GR agonists are efficacious for treatment of inflammatory, allergic, and immunological disorders. Steroid hormone binding to the ligand-binding domain (LBD) of GR is known to change the structural and dynamical properties of the receptor, which in turn control its interactions with DNA and various co-regulators and drive the pharmacological response. Previous biophysical studies of the GR LBD have required the use of mutant forms to overcome issues with limited protein stability and high aggregation propensity. However, these mutant variants are known to also influence the functional response of the receptor. Here we report a successful protocol for protein expression, purification, and NMR characterization of the wildtype human GR LBD. We achieved chemical shift assignments for 90% of the LBD backbone resonances, with 216 out of 240 non-proline residues assigned in the 1H-15N TROSY spectrum. These advancements form the basis for future investigations of allosteric effects in GR signaling.