Crystal structure of the mineralocorticoid receptor ligand-binding domain in complex with a potent and selective nonsteroidal blocker, esaxerenone (CS-3150).

Activation of the mineralocorticoid receptor (MR) has long been considered a risk factor for cardiovascular diseases. It has been reported that the novel MR blocker esaxerenone shows high potency and selectivity for MR in vitro as well as great anti-hypertensive and renoprotective effects in salt-sensitive hypertensive rats. Here, we determined the co-crystal structure of the MR ligand binding domain (MR-LBD) with esaxerenone and found that esaxerenone binds to MR-LBD in a unique manner with large side-chain rearrangements, distinct from those of previously published MR antagonists. This structure also displays an antagonist form that has not been observed for MR previously. Such a unique binding mode of esaxerenone provides great insight into the novelty, potency and selectivity of this novel anti-hypertensive drug.