Biological Assembly 1  

 3D View: Structure | 1D-3D View | Electron Density | Validation Report | Ligand Interaction | Predict Membrane 

Global Symmetry: Cyclic - C3  (3D View)
Global Stoichiometry: Homo 6-mer - A6 

Biological assembly 1 assigned by authors and generated by PISA (software)

Macromolecule Content

• Total Structure Weight: 49.01 kDa 
• Atom Count: 2350 
• Modelled Residue Count: 325 
• Deposited Residue Count: 428 
• Unique protein chains: 1

4HKR

Calcium release-activated calcium (CRAC) channel ORAI

• PDB DOI: 10.2210/pdb4HKR/pdb

• Classification: TRANSPORT PROTEIN
• Organism(s): Drosophila melanogaster
• Expression System: Komagataella pastoris
• Mutation(s): Yes 
• Membrane Protein: Yes  OPMPDBTMMemProtMDmpstruc


• Deposited: 2012-10-15 Released: 2012-11-28 
• Deposition Author(s): Long, S.B., Hou, X.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 3.35 Å
• R-Value Free: 0.279 
• R-Value Work: 0.278 
• R-Value Observed: 0.278 

Literature

Crystal structure of the calcium release-activated calcium channel Orai.

Hou, X., Pedi, L., Diver, M.M., Long, S.B.

(2012) Science 338: 1308-1313

• PubMed: 23180775 
• DOI: 10.1126/science.1228757
• Primary Citation of Related Structures:  
  4HKR, 4HKS


• PubMed Abstract: 
  

The plasma membrane protein Orai forms the pore of the calcium release-activated calcium (CRAC) channel and generates sustained cytosolic calcium signals when triggered by depletion of calcium from the endoplasmic reticulum. The crystal structure of Orai from Drosophila melanogaster, determined at 3.35 angstrom resolution, reveals that the calcium channel is composed of a hexameric assembly of Orai subunits arranged around a central ion pore. The pore traverses the membrane and extends into the cytosol. A ring of glutamate residues on its extracellular side forms the selectivity filter. A basic region near the intracellular side can bind anions that may stabilize the closed state. The architecture of the channel differs markedly from other ion channels and gives insight into the principles of selective calcium permeation and gating.

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Organizational Affiliation: 

Structural Biology Program, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Calcium release-activated calcium channel protein 1	A, B	214	Drosophila melanogaster	Mutation(s): 4  Gene Names: olf186-F, CRACM1, olf186, CG11430, Orai Membrane Entity: Yes
UniProt
Find proteins for Q9U6B8 (Drosophila melanogaster) Explore Q9U6B8  Go to UniProtKB:  Q9U6B8

Small Molecules

Ligands 3 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
BA	C [auth A]	BARIUM ION Ba XDFCIPNJCBUZJN-UHFFFAOYSA-N
ZN	D [auth A]	ZINC ION Zn PTFCDOFLOPIGGS-UHFFFAOYSA-N
FE	E [auth A], F [auth A]	FE (III) ION Fe VTLYFUHAOXGGBS-UHFFFAOYSA-N

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 3.35 Å
• R-Value Free: 0.279 
• R-Value Work: 0.278 
• R-Value Observed: 0.278 
• Space Group: P 2₁ 3

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 117.91	α = 90
b = 117.91	β = 90
c = 117.91	γ = 90

Software Package:

Software Name	Purpose
CBASS	data collection
SHARP	phasing
PHASER	phasing
PHENIX	refinement
HKL-2000	data reduction
HKL-2000	data scaling
CNS	refinement

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2012-10-15 
• Released Date: 2012-11-28 
Deposition Author(s): Long, S.B., Hou, X.

Revision History  

• Version 1.0: 2012-11-28
  Type: Initial release
  
• Version 1.1: 2012-12-12
  Changes: Database references
• Version 1.2: 2012-12-26
  Changes: Database references