6X4G

Crystal structure of ICOS in complex with ICOS-L and an anti ICOS-L VNAR domain


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.50 Å
  • R-Value Free: 0.267 
  • R-Value Work: 0.224 
  • R-Value Observed: 0.226 

Starting Models: experimental
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This is version 1.2 of the entry. See complete history


Literature

Structural characterization of the ICOS/ICOS-L immune complex reveals high molecular mimicry by therapeutic antibodies.

Rujas, E.Cui, H.Sicard, T.Semesi, A.Julien, J.P.

(2020) Nat Commun 11: 5066-5066

  • DOI: https://doi.org/10.1038/s41467-020-18828-4
  • Primary Citation of Related Structures:  
    6X4G, 6X4T, 7JOO

  • PubMed Abstract: 

    The inducible co-stimulator (ICOS) is a member of the CD28/B7 superfamily, and delivers a positive co-stimulatory signal to activated T cells upon binding to its ligand (ICOS-L). Dysregulation of this pathway has been implicated in autoimmune diseases and cancer, and is currently under clinical investigation as an immune checkpoint blockade. Here, we describe the molecular interactions of the ICOS/ICOS-L immune complex at 3.3 Å resolution. A central FDPPPF motif and residues within the CC' loop of ICOS are responsible for the specificity of the interaction with ICOS-L, with a distinct receptor binding orientation in comparison to other family members. Furthermore, our structure and binding data reveal that the ICOS N110 N-linked glycan participates in ICOS-L binding. In addition, we report crystal structures of ICOS and ICOS-L in complex with monoclonal antibodies under clinical evaluation in immunotherapy. Strikingly, antibody paratopes closely mimic receptor-ligand binding core interactions, in addition to contacting peripheral residues to confer high binding affinities. Our results uncover key molecular interactions of an immune complex central to human adaptive immunity and have direct implications for the ongoing development of therapeutic interventions targeting immune checkpoint receptors.


  • Organizational Affiliation

    Program in Molecular Medicine, The Hospital for Sick Children Research Institute, Toronto, ON, M5G 0A4, Canada.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Inducible T-cell costimulator119Homo sapiensMutation(s): 0 
Gene Names: ICOSAILIM
UniProt & NIH Common Fund Data Resources
Find proteins for Q9Y6W8 (Homo sapiens)
Go to UniProtKB:  Q9Y6W8
PHAROS:  Q9Y6W8
GTEx:  ENSG00000163600 
Glycosylation
Glycosylation Sites: 2Go to GlyGen: Q9Y6W8-1
Sequence Annotations
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  • Reference Sequence
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 2
MoleculeChains Sequence LengthOrganismDetailsImage
ICOS ligandB [auth C]240Homo sapiensMutation(s): 0 
Gene Names: ICOSLGB7H2B7RP1ICOSLKIAA0653
UniProt & NIH Common Fund Data Resources
Find proteins for O75144 (Homo sapiens)
Go to UniProtKB:  O75144
PHAROS:  O75144
GTEx:  ENSG00000160223 
Glycosylation
Glycosylation Sites: 6Go to GlyGen: O75144-1
Sequence Annotations
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  • Reference Sequence
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 3
MoleculeChains Sequence LengthOrganismDetailsImage
anti ICOS-L VHH domain VNARC [auth N]130Orectolobus maculatusMutation(s): 0 
Sequence Annotations
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  • Reference Sequence
Oligosaccharides

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Entity ID: 4
MoleculeChains Length2D Diagram Glycosylation3D Interactions
alpha-D-mannopyranose-(1-3)-[alpha-D-mannopyranose-(1-6)]beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranoseD [auth B],
E [auth D]
5N-Glycosylation
Glycosylation Resources
GlyTouCan:  G22768VO
GlyCosmos:  G22768VO
GlyGen:  G22768VO
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.50 Å
  • R-Value Free: 0.267 
  • R-Value Work: 0.224 
  • R-Value Observed: 0.226 
  • Space Group: P 41 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 104.015α = 90
b = 104.015β = 90
c = 123.108γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
XDSdata reduction
XSCALEdata scaling
PHASERphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Canadian Institutes of Health Research (CIHR)CanadaPJT-1488

Revision History  (Full details and data files)

  • Version 1.0: 2020-10-14
    Type: Initial release
  • Version 1.1: 2020-10-21
    Changes: Database references
  • Version 1.2: 2023-10-18
    Changes: Data collection, Database references, Refinement description