5HK2

Human sigma-1 receptor bound to 4-IBP


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.20 Å
  • R-Value Free: 0.261 
  • R-Value Work: 0.218 
  • R-Value Observed: 0.223 

Starting Model: experimental
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Ligand Structure Quality Assessment 


This is version 1.4 of the entry. See complete history


Literature

Crystal structure of the human sigma 1 receptor.

Schmidt, H.R.Zheng, S.Gurpinar, E.Koehl, A.Manglik, A.Kruse, A.C.

(2016) Nature 532: 527-530

  • DOI: https://doi.org/10.1038/nature17391
  • Primary Citation of Related Structures:  
    5HK1, 5HK2

  • PubMed Abstract: 

    The human σ1 receptor is an enigmatic endoplasmic-reticulum-resident transmembrane protein implicated in a variety of disorders including depression, drug addiction, and neuropathic pain. Recently, an additional connection to amyotrophic lateral sclerosis has emerged from studies of human genetics and mouse models. Unlike many transmembrane receptors that belong to large, extensively studied families such as G-protein-coupled receptors or ligand-gated ion channels, the σ1 receptor is an evolutionary isolate with no discernible similarity to any other human protein. Despite its increasingly clear importance in human physiology and disease, the molecular architecture of the σ1 receptor and its regulation by drug-like compounds remain poorly defined. Here we report crystal structures of the human σ1 receptor in complex with two chemically divergent ligands, PD144418 and 4-IBP. The structures reveal a trimeric architecture with a single transmembrane domain in each protomer. The carboxy-terminal domain of the receptor shows an extensive flat, hydrophobic membrane-proximal surface, suggesting an intimate association with the cytosolic surface of the endoplasmic reticulum membrane in cells. This domain includes a cupin-like β-barrel with the ligand-binding site buried at its centre. This large, hydrophobic ligand-binding cavity shows remarkable plasticity in ligand recognition, binding the two ligands in similar positions despite dissimilar chemical structures. Taken together, these results reveal the overall architecture, oligomerization state, and molecular basis for ligand recognition by this important but poorly understood protein.


  • Organizational Affiliation

    Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Sigma non-opioid intracellular receptor 1
A, B, C
227Homo sapiensMutation(s): 0 
Gene Names: SIGMAR1OPRS1SRBPAAG8
Membrane Entity: Yes 
UniProt & NIH Common Fund Data Resources
Find proteins for Q99720 (Homo sapiens)
Explore Q99720 
Go to UniProtKB:  Q99720
PHAROS:  Q99720
GTEx:  ENSG00000147955 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ99720
Sequence Annotations
Expand
  • Reference Sequence
Small Molecules
Ligands 3 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
61V
Query on 61V

Download Ideal Coordinates CCD File 
D [auth A],
H [auth B],
R [auth C]
N-(1-benzylpiperidin-4-yl)-4-iodobenzamide
C19 H21 I N2 O
HELCSESNNDZLFM-UHFFFAOYSA-N
OLC
Query on OLC

Download Ideal Coordinates CCD File 
M [auth B]
N [auth B]
O [auth B]
P [auth B]
Q [auth B]
M [auth B],
N [auth B],
O [auth B],
P [auth B],
Q [auth B],
X [auth C],
Y [auth C]
(2R)-2,3-dihydroxypropyl (9Z)-octadec-9-enoate
C21 H40 O4
RZRNAYUHWVFMIP-GDCKJWNLSA-N
SO4
Query on SO4

Download Ideal Coordinates CCD File 
E [auth A]
F [auth A]
G [auth A]
I [auth B]
J [auth B]
E [auth A],
F [auth A],
G [auth A],
I [auth B],
J [auth B],
K [auth B],
L [auth B],
S [auth C],
T [auth C],
U [auth C],
V [auth C],
W [auth C]
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
Binding Affinity Annotations 
IDSourceBinding Affinity
61V BindingDB:  5HK2 Ki: min: 1.7, max: 1.7 (nM) from 2 assay(s)
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.20 Å
  • R-Value Free: 0.261 
  • R-Value Work: 0.218 
  • R-Value Observed: 0.223 
  • Space Group: P 21 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 85.7α = 90
b = 126.8β = 90
c = 110.8γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
XSCALEdata scaling
Cootmodel building
SHARPphasing
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2016-04-06
    Type: Initial release
  • Version 1.1: 2016-04-20
    Changes: Database references
  • Version 1.2: 2016-05-11
    Changes: Database references
  • Version 1.3: 2017-11-22
    Changes: Database references, Derived calculations, Refinement description
  • Version 1.4: 2023-09-27
    Changes: Data collection, Database references, Refinement description