The structural diversity of psychedelic drug actions revealed

Ryan H Gumpper^#^{1

2}, Manish K Jain^#³, Kuglae Kim⁴, Renhong Sun⁵, Ning Sun⁵, Zhongli Xu⁵, Jeffrey F DiBerto^{3

6}, Brian E Krumm³, Nicholas J Kapolka⁶, H Ümit Kaniskan⁵, David E Nichols⁷, Jian Jin⁵, Jonathan F Fay⁸, Bryan L Roth^{9

10}

Affiliations

¹ Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA. rgumpper@email.unc.edu.
² Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC, USA. rgumpper@email.unc.edu.
³ Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA.
⁴ Department of Pharmacy, College of Pharmacy, Yonsei University, Incheon, Korea.
⁵ Mount Sinai Center for Therapeutics Discovery, Departments of Pharmacological Sciences, Oncological Sciences and Neuroscience, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
⁶ EvE Bio, LLC, Durham, NC, USA.
⁷ Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC, USA.
⁸ Department of Biochemistry and Molecular Biology, University of Maryland Baltimore, Baltimore, MD, USA.
⁹ Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA. bryan_roth@med.unc.edu.
¹⁰ Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC, USA. bryan_roth@med.unc.edu.

^# Contributed equally.

PMID: 40108183
PMCID: PMC11923220
DOI: 10.1038/s41467-025-57956-7

The structural diversity of psychedelic drug actions revealed

Ryan H Gumpper et al. Nat Commun. 2025.

. 2025 Mar 19;16(1):2734.

doi: 10.1038/s41467-025-57956-7.

Authors

Affiliations

¹ Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA. rgumpper@email.unc.edu.
² Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC, USA. rgumpper@email.unc.edu.
³ Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA.
⁴ Department of Pharmacy, College of Pharmacy, Yonsei University, Incheon, Korea.
⁵ Mount Sinai Center for Therapeutics Discovery, Departments of Pharmacological Sciences, Oncological Sciences and Neuroscience, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
⁶ EvE Bio, LLC, Durham, NC, USA.
⁷ Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC, USA.
⁸ Department of Biochemistry and Molecular Biology, University of Maryland Baltimore, Baltimore, MD, USA.
⁹ Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA. bryan_roth@med.unc.edu.
¹⁰ Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC, USA. bryan_roth@med.unc.edu.

^# Contributed equally.

PMID: 40108183
PMCID: PMC11923220
DOI: 10.1038/s41467-025-57956-7

Abstract

There is currently a resurgence in exploring the utility of classical psychedelics to treat depression, addiction, anxiety disorders, cluster headaches, and many other neuropsychiatric disorders. A biological target of these compounds, and a hypothesized target for their therapeutic actions, is the 5-HT_2A serotonin receptor. Here, we present 7 cryo-EM structures covering all major compound classes of psychedelic and non-psychedelic agonists, including a β-arrestin-biased compound RS130-180. Identifying the molecular interactions between various psychedelics and the 5-HT_2A receptor reveals both common and distinct motifs among the examined psychedelic chemotypes. These findings lead to a broader mechanistic understanding of 5-HT_2A activation, which can catalyze the development of novel chemotypes with potential therapeutic utility and fewer side effects.

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Conflict of interest statement

Competing interests: R.H.G is an active consultant for 2A Biosciences. B.L.R. is a member of the SAB for Onsero, Escient, Septerna, Epiodyne, and Levator. J.J. is a cofounder and equity shareholder in Cullgen, Inc., a scientific cofounder and scientific advisory board member of Onsero Therapeutics, Inc., and a consultant for Cullgen, Inc., EpiCypher, Inc., Accent Therapeutics, Inc, and Tavotek Biotherapeutics, Inc. The Jin laboratory received or has received research funds from Celgene Corporation, Levo Therapeutics, Inc., Cullgen, Inc., and Cullinan Oncology, Inc. D.E.N. is a founder of 2A Biosciences. The remaining authors declare no competing interests.

Figures

**Fig. 1. Cryo-EM Structures of the 5-HT_2AR with Various Psychedelic Ligands.**
All of the structures collected and analyzed in this work separated into the main ligand classes: tryptamines, ergolines, and phenethylamines. The local map, global map, ligand densities from the local map, and the resolution are given for each structure. All the maps shown were created from the half-maps utilizing deepEMhancer and the highRes model. However, the ligand densities are from the automatically sharpened output of the Local Refinement job in cryosparc. To maintain consistency, the receptor coordinates for both the global and local depositions remain identical and are modeled on the local refined map. All images were prepared using ChimeraX. The cartoon models shown in the bottom left represent all the receptors aligned to the 5-HT structure exhibiting the structural homogeneity between the ligands tested.

**Fig. 2. Receptor Ligand Interactions in the Orthosteric Pocket for Tryptamine and Phenethylamines.**
A–C Modeled interactions are shown by the dotted yellow line and based on the modeled distances from the cryo-EM structures. Each residue for the receptor is labeled by the Ballesteros–Weinstein (BW) numbering scheme. Each panel exhibits the structures: (A) 5-HT, (B) Psilocin, and (C) DMT. D, E Overlay of either 5-HT and Psilocin (D) or 5-HT and DMT (E). F, G Showcase the electrostatic interactions of either LSD (F) or BOL (G) shown in the dotted yellow line. H BOL and selected residues at the bottom of the orthosteric pocket shown as vdW spheres. I Overlay of 5-HT_2AR with either LSD or BOL from this work, 5-HT_2BR with LSD (PDB: 7SRQ), and D₂R LSD (PDB: 9BS9 (unpublished)).

**Fig. 3. Molecular Interactions and Mechanisms of Phenethylamines.**
A, B Showcases the binding mode and modeled electrostatic interactions of mescaline (A) and the novel arrestin-biased compound RS130-180 (B). C Top panel shows the vdW sphere of mescaline and L229^45.52/F234^5.38. The bottom two panels indicate the TRUPATH assays and site-directed mutagenesis for each residue. Each point represents the mean ± SEM and N = 3 biological replicates. It is of note that the negative curve-fit shown in this panel is for visualization purposes of the inverse agonism only – no fit parameters were obtained from this fit. D Chemical representation of RS130-180. The top right panel represents the overlay of the 5-HT structure (blue), RS130-180 (pink), and an inactive state structure (gray, PDB ID: 6A93) as shown via cartoon representation. The dose-response curve for Gq (TRUPATH) and arrestin for RS130-180 showcases the arrestin bias of the compound. Each point represents the mean ± SEM and N = 3 biological replicates and is taken from the raw data in Supplementary Fig. 13 and Supplementary Table 8. The bottom portion is close-up panels showcasing the structural mechanism that RS130-180 utilizes to achieve its arrestin bias.

**Fig. 4. Aggregate Molecular Interactions.**
Selected important residues within the orthosteric pocket colored by their various selective properties across all the ligands examined in this study as well as two other active state structures. Each conglomerate of interactions is colored differently to indicate common/different interactions between chemotypes or individual compounds. Abbreviations are as follows: serotonin (5-HT), tryptamines (Trp), ergolines (Erg), 2-bromo-LSD (BOL), mescaline (MSC), 25CN-NBOH (NBOH), and N,N-dimethyltryptamine (DMT).

**Fig. 5. Differences in Signaling Reveal Distinct Conformational States of Psychedelics.**
A Bias plots (Gq activation vs β-arr2 activation) from the time course seen in Supplementary Fig. 13 and Supplementary Table 8. B Cartoon of Nb6 dissociation and the time course of 5-HT. Data represent N = 3 biological replicates and mean ± SEM. Created in BioRender. Gumpper, R. (2025) https://BioRender.com/u71s141 (C) The calculated activation of each signaling assay matched for time (55 mins for Nb6 and 60 min for Gq/β-arr2) and concentration. For the NB6 assays, this data represents N = 3 biological replicates. For Gq/β-arr2, the calculated activation is based on the fit parameters at 60 minutes and matched for concentration. These fit parameters can be found in Supplementary Fig. 13 and Supplementary Table 8, where the number of biological replicates is also recorded. D Workflow of the output from cryoSPARC 3DFlex to generate models for downstream analysis and dimensionality reduction. E Aggregate data of the flexibility analysis using the Flex-refine protocol in cryoSPARC reveals conformational selectivity of the ligands. This is a UMAP of the models derived from the maps output by 3DFlex. Each color represents a different ligand, and abbreviations are as follows: mescaline (MSC), N,N-dimethyltryptamine (DMT), serotonin (5HT), 2-bromo-LSD (BOL).

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References

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The structural diversity of psychedelic drug actions revealed

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The structural diversity of psychedelic drug actions revealed

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