3F62

Crystal Structure of Human IL-18 in complex with Ectromelia virus IL-18 Binding Protein


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2 Å
  • R-Value Free: 0.235 
  • R-Value Work: 0.189 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Structural basis for antagonism of human interleukin 18 by poxvirus interleukin 18-binding protein.

Krumm, B.Meng, X.Li, Y.Xiang, Y.Deng, J.

(2008) Proc.Natl.Acad.Sci.USA 105: 20711-20715

  • DOI: 10.1073/pnas.0809086106

  • PubMed Abstract: 
  • Human interleukin-18 (hIL-18) is a cytokine that plays an important role in inflammation and host defense against microbes. Its activity is regulated in vivo by a naturally occurring antagonist, the human IL-18-binding protein (IL-18BP). Functional h ...

    Human interleukin-18 (hIL-18) is a cytokine that plays an important role in inflammation and host defense against microbes. Its activity is regulated in vivo by a naturally occurring antagonist, the human IL-18-binding protein (IL-18BP). Functional homologs of human IL-18BP are encoded by all orthopoxviruses, including variola virus, the causative agent of smallpox. They contribute to virulence by suppressing IL-18-mediated immune responses. Here, we describe the 2.0-A resolution crystal structure of an orthopoxvirus IL-18BP, ectromelia virus IL-18BP (ectvIL-18BP), in complex with hIL-18. The hIL-18 structure in the complex shows significant conformational change at the binding interface compared with the structure of ligand-free hIL-18, indicating that the binding is mediated by an induced-fit mechanism. EctvIL-18BP adopts a canonical Ig fold and interacts via one edge of its beta-sandwich with 3 cavities on the hIL-18 surface through extensive hydrophobic and hydrogen bonding interactions. Most of the ectvIL-18BP residues that participate in these interactions are conserved in both human and viral homologs, explaining their functional equivalence despite limited sequence homology. EctvIL-18BP blocks a putative receptor-binding site on IL-18, thus preventing IL-18 from engaging its receptor. Our structure provides insights into how IL-18BPs modulate hIL-18 activity. The revealed binding interface provides the basis for rational design of inhibitors against orthopoxvirus IL-18BP (for treating orthopoxvirus infection) or hIL-18 (for treating certain inflammatory and autoimmune diseases).


    Organizational Affiliation

    Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK 74078, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Interleukin 18 binding protein
A
109Ectromelia virusMutation(s): 0 
Gene Names: p16 (EVH019, EVM013)
Find proteins for Q85319 (Ectromelia virus)
Go to UniProtKB:  Q85319
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
Interleukin-18
B
158Homo sapiensMutation(s): 4 
Gene Names: IL18 (IGIF, IL1F4)
Find proteins for Q14116 (Homo sapiens)
Go to Gene View: IL18
Go to UniProtKB:  Q14116
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2 Å
  • R-Value Free: 0.235 
  • R-Value Work: 0.189 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 36.356α = 90.00
b = 69.210β = 90.00
c = 104.832γ = 90.00
Software Package:
Software NamePurpose
PDB_EXTRACTdata extraction
HKL-3000data reduction
HKL-3000data scaling
HKL-3000data collection
SHELXSphasing
REFMACrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2009-01-06
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Advisory, Version format compliance