2VXT

Crystal structure of human IL-18 complexed to murine reference antibody 125-2H Fab


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.49 Å
  • R-Value Free: 0.196 
  • R-Value Work: 0.162 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Unusual Water-Mediated Antigenic Recognition of the Proinflammatory Cytokine Interleukin-18.

Argiriadi, M.A.Xiang, T.Wu, C.Ghayur, T.Borhani, D.W.

(2009) J.Biol.Chem. 284: 24478

  • DOI: 10.1074/jbc.M109.023887
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • The unique cytokine interleukin-18 (IL-18) acts synergistically with IL-12 to regulate T-helper 1 and 2 lymphocytes and, as such, seems to underlie the pathogenesis of various autoimmune and allergic diseases. Several anti-IL-18 agents are in clinica ...

    The unique cytokine interleukin-18 (IL-18) acts synergistically with IL-12 to regulate T-helper 1 and 2 lymphocytes and, as such, seems to underlie the pathogenesis of various autoimmune and allergic diseases. Several anti-IL-18 agents are in clinical development, including the recombinant human antibody ABT-325, which is entering trials for autoimmune diseases. Given competing cytokine/receptor and cytokine/receptor decoy interactions, understanding the structural basis for recognition is critical for effective development of anti-cytokine therapies. Here we report three crystal structures: the murine antibody 125-2H Fab fragment bound to human IL-18, at 1.5 A resolution; the 125-2H Fab (2.3 A); and the ABT-325 Fab (1.5 A). These structures, along with human/mouse IL-18 chimera binding data, allow us to make three key observations relevant to the biology and antigenic recognition of IL-18 and related cytokines. First, several IL-18 residues shift dramatically (> 10 A) upon binding 125-2H, compared with unbound IL-18 (Kato, Z., Jee, J., Shikano, H., Mishima, M., Ohki, I., Ohnishi, H., Li, A., Hashimoto, K., Matsukuma, E., Omoya, K., Yamamoto, Y., Yoneda, T., Hara, T., Kondo, N., and Shirakawa, M. (2003) Nat. Struct. Biol. 10, 966-971). IL-18 thus exhibits plasticity that may be common to its interactions with other receptors. Related cytokines may exhibit similar plasticity. Second, ABT-325 and 125-2H differ significantly in combining site character and architecture, thus explaining their ability to bind IL-18 simultaneously at distinct epitopes. These data allow us to define the likely ABT-325 epitope and thereby explain the distinct neutralizing mechanisms of both antibodies. Third, given the high 125-2H potency, 10 well ordered water molecules are trapped upon complex formation in a cavity between two IL-18 loops and all six 125-2H complementarity-determining regions. Thus, counterintuitively, tight and specific antibody binding may in some cases be water-mediated.


    Organizational Affiliation

    Department of Biochemistry, Abbott Laboratories, Worcester, Massachusetts 01605, USA. maria.argiriadi@abbott.com




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
MURINE IGG 125-2H
H
216N/AMutation(s): 0 
Protein Feature View is not available: No corresponding UniProt sequence found.
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
INTERLEUKIN-18
I
157Homo sapiensMutation(s): 4 
Gene Names: IL18 (IGIF, IL1F4)
Find proteins for Q14116 (Homo sapiens)
Go to Gene View: IL18
Go to UniProtKB:  Q14116
Entity ID: 3
MoleculeChainsSequence LengthOrganismDetails
MURINE IGG 125-2H
L
214N/AMutation(s): 0 
Protein Feature View is not available: No corresponding UniProt sequence found.
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
CL
Query on CL

Download SDF File 
Download CCD File 
H, I
CHLORIDE ION
Cl
VEXZGXHMUGYJMC-UHFFFAOYSA-M
 Ligand Interaction
MG
Query on MG

Download SDF File 
Download CCD File 
I
MAGNESIUM ION
Mg
JLVVSXFLKOJNIY-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.49 Å
  • R-Value Free: 0.196 
  • R-Value Work: 0.162 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 44.345α = 90.00
b = 62.435β = 100.39
c = 104.734γ = 90.00
Software Package:
Software NamePurpose
HKL-2000data reduction
SCALEPACKdata scaling
AMoREphasing
REFMACrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2009-06-23
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Advisory, Version format compliance