3DUH

Structure of Interleukin-23


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.3 Å
  • R-Value Free: 0.268 
  • R-Value Work: 0.228 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

The structure of interleukin-23 reveals the molecular basis of p40 subunit sharing with interleukin-12.

Lupardus, P.J.Garcia, K.C.

(2008) J.Mol.Biol. 382: 931-941

  • DOI: 10.1016/j.jmb.2008.07.051

  • PubMed Abstract: 
  • Interleukin (IL)-23 is a recently identified member of the IL-12 family of heterodimeric cytokines that modulate subpopulations of T helper cells, and both IL-12 and IL-23 are attractive targets for therapy of autoimmune diseases. IL-23 is a binary c ...

    Interleukin (IL)-23 is a recently identified member of the IL-12 family of heterodimeric cytokines that modulate subpopulations of T helper cells, and both IL-12 and IL-23 are attractive targets for therapy of autoimmune diseases. IL-23 is a binary complex of a four-helix bundle cytokine (p19) and a soluble class I cytokine receptor p40. IL-12 and IL-23 share p40 as an alpha-receptor subunit, yet show only 15% sequence homology between their four-helix cytokines p19 and p35, respectively, and signal through different combinations of shared receptors. In order to elucidate the structural basis of p40 sharing, we have determined a 2.3-A crystal structure of IL-23 for comparison to the previously determined structure of IL-12. The docking mode of p19 to p40 is altered compared to p35, deviating by a 'tilt' and 'roll' that results in an altered footprint of p40 on the A and D helices of the respective cytokines. Binding of p19 to p40 is mediated primarily by an arginine residue on helix D of p19 that forms an extensive charge and hydrogen-bonding network with residues at the base of a pocket on p40. This 'arginine pocket' is lined with an inner shell of hydrophobic interactions that are ringed by an outer shell of polar interactions. Comparative analysis indicates that the IL-23 and IL-12 complexes 'mimic' the network of interactions constituting the central arginine pocket despite p19 and p35 having limited sequence homology. The majority of the structural epitopes in the two complexes are composed of unique p19 and p35 pairwise contacts with common residues on p40. Thus, while the critical hotspot is maintained in the two complexes, the majority of the interfaces are structurally distinct and, therefore, provide a basis for the therapeutic targeting of IL-12 versus IL-23 heterodimer formation despite their use of a common receptor subunit.


    Organizational Affiliation

    Howard Hughes Medical Institute, Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Interleukin-12 subunit beta
A, B
314Homo sapiensMutation(s): 0 
Gene Names: IL12B (NKSF2)
Find proteins for P29460 (Homo sapiens)
Go to Gene View: IL12B
Go to UniProtKB:  P29460
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
Interleukin-23 subunit alpha
C, D
177Homo sapiensMutation(s): 0 
Gene Names: IL23A (SGRF)
Find proteins for Q9NPF7 (Homo sapiens)
Go to Gene View: IL23A
Go to UniProtKB:  Q9NPF7
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
NAG
Query on NAG

Download SDF File 
Download CCD File 
A, B
N-ACETYL-D-GLUCOSAMINE
C8 H15 N O6
OVRNDRQMDRJTHS-FMDGEEDCSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.3 Å
  • R-Value Free: 0.268 
  • R-Value Work: 0.228 
  • Space Group: C 1 2 1
Unit Cell:
Length (Å)Angle (°)
a = 116.089α = 90.00
b = 59.974β = 90.46
c = 160.365γ = 90.00
Software Package:
Software NamePurpose
HKL-2000data collection
SCALAdata scaling
REFMACrefinement
PHASERphasing
MOSFLMdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2008-08-19
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Non-polymer description, Version format compliance