9MFM | pdb_00009mfm

Structure of zebrafish OTOP1 in nanodisc in complex with inhibitor C2.36


Experimental Data Snapshot

  • Method: ELECTRON MICROSCOPY
  • Resolution: 3.42 Å
  • Aggregation State: PARTICLE 
  • Reconstruction Method: SINGLE PARTICLE 

Starting Model: experimental
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wwPDB Validation 3D Report Full Report

Validation slider image for 9MFM

This is version 1.0 of the entry. See complete history

Literature

Structure-guided discovery of Otopetrin 1 inhibitors reveals druggable binding sites at the intrasubunit interface.

Burendei, B.Kaplan, J.P.Orellana, G.M.Liman, E.R.Forli, S.Ward, A.B.

(2025) Nat Commun 16: 9362-9362

  • DOI: https://doi.org/10.1038/s41467-025-64392-0
  • Primary Citation Related Structures: 
    9MFF, 9MFL, 9MFM

  • PubMed Abstract: 

    Proton conductance across cell membranes serves many biological functions, ranging from the regulation of intracellular and extracellular pH to the generation of electrical signals that lead to sour taste perception. Otopetrins (OTOPs) are a conserved, eukaryotic family of proton-selective ion channels, one of which (OTOP1) serves as a gustatory sensor for sour tastes and ammonium chloride. As the functional properties and structures of OTOP channels were only recently described, there are presently few tools available to modulate their activity. Here, we perform subsequent rounds of molecular docking-based virtual screening against the structure of zebrafish OTOP1, followed by functional testing using whole-cell patch-clamp electrophysiology, and identify several small molecule inhibitors that are effective in the low-to-mid µM range. Cryo-electron microscopy structures reveal inhibitor binding sites in the intrasubunit interface that are validated by functional testing of mutant channels. Our findings reveal pockets that can be targeted for small molecule discovery to develop modulators for Otopetrins. Such modulators can serve as useful toolkit molecules for future investigations of structure-function relationships or physiological roles of Otopetrins.


  • Organizational Affiliation
    • Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, USA.

Macromolecule Content 

  • Total Structure Weight: 136.03 kDa 
  • Atom Count: 6,148 
  • Modeled Residue Count: 734 
  • Deposited Residue Count: 1,174 
  • Unique protein chains: 1

Macromolecules

Find similar proteins by:|  3D Structure
Entity ID: 1
MoleculeChains  Sequence LengthOrganismDetailsImage
Proton channel OTOP1
A, B
587Danio rerioMutation(s): 0 
Gene Names: otop1
UniProt
Find proteins for Q7ZWK8 (Danio rerio)
Explore Q7ZWK8 
Go to UniProtKB:  Q7ZWK8
Entity Groups
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ7ZWK8
Sequence Annotations
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Reference Sequence

Small Molecules

Ligands 3 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Y01

Query on Y01



Download:Ideal Coordinates CCD File
C [auth A],
D [auth A],
I [auth B],
J [auth B]
CHOLESTEROL HEMISUCCINATE
C31 H50 O4
WLNARFZDISHUGS-MIXBDBMTSA-N
CLR

Query on CLR



Download:Ideal Coordinates CCD File
E [auth A],
K [auth B]
CHOLESTEROL
C27 H46 O
HVYWMOMLDIMFJA-DPAQBDIFSA-N
A1BKT
(Subject of Investigation/LOI)

Query on A1BKT



Download:Ideal Coordinates CCD File
F [auth A]
G [auth A]
H [auth A]
L [auth B]
M [auth B]
F [auth A],
G [auth A],
H [auth A],
L [auth B],
M [auth B],
N [auth B]
4-[(4R)-5H,11H-[1,2,4]triazolo[3,4-c][1,4]benzoxazepin-3-yl]phenol
C16 H13 N3 O2
YIVKZBDNZIXFKW-UHFFFAOYSA-N

Experimental Data & Validation

Experimental Data

  • Method: ELECTRON MICROSCOPY
  • Resolution: 3.42 Å
  • Aggregation State: PARTICLE 
  • Reconstruction Method: SINGLE PARTICLE 
EM Software:
TaskSoftware PackageVersion
MODEL REFINEMENTPHENIX1.20.1_4487:

Structure Validation

View Full Validation Report



Entry History 

& Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Not fundedUnited States--

Revision History  (Full details and data files)

  • Version 1.0: 2025-11-05
    Type: Initial release