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Publication Abstract from PubMed

The sigma-1 receptor (sigma1R) is a non-opioid membrane receptor, which responds to a diverse array of synthetic ligands to exert various pharmacological effects. Meanwhile, candidates for endogenous ligands of sigma1R have also been identified. However, how endogenous ligands bind to sigma1R remains unknown. Here, we present crystal structures of sigma1R from Xenopus laevis (xlsigma1R) bound to two endogenous neurosteroid ligands, progesterone (a putative antagonist) and dehydroepiandrosterone sulfate (DHEAS) (a putative agonist), at 2.15-3.09 A resolutions. Both neurosteroids bind to a similar location in xlsigma1R mainly through hydrophobic interactions, but surprisingly, with opposite binding orientations. DHEAS also forms hydrogen bonds with xlsigma1R, whereas progesterone interacts indirectly with the receptor through water molecules near the binding site. Binding analyses are consistent with the xlsigma1R-neurosteroid complex structures. Furthermore, molecular dynamics simulations and structural data reveal a potential water entry pathway. Our results provide insight into binding of two endogenous neurosteroid ligands to sigma1R.

Insight into binding of endogenous neurosteroid ligands to the sigma-1 receptor.,Fu C, Xiao Y, Zhou X, Sun Z Nat Commun. 2024 Jul 4;15(1):5619. doi: 10.1038/s41467-024-49894-7. PMID:38965213^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.