5VKM

Crystal structure of human CD22 Ig domains 1-3 in complex with alpha 2-6 sialyllactose


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.2 Å
  • R-Value Free: 0.254 
  • R-Value Work: 0.210 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Molecular basis of human CD22 function and therapeutic targeting.

Ereno-Orbea, J.Sicard, T.Cui, H.Mazhab-Jafari, M.T.Benlekbir, S.Guarne, A.Rubinstein, J.L.Julien, J.P.

(2017) Nat Commun 8: 764-764

  • DOI: 10.1038/s41467-017-00836-6
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • CD22 maintains a baseline level of B-cell inhibition to keep humoral immunity in check. As a B-cell-restricted antigen, CD22 is targeted in therapies against dysregulated B cells that cause autoimmune diseases and blood cancers. Here we report the cr ...

    CD22 maintains a baseline level of B-cell inhibition to keep humoral immunity in check. As a B-cell-restricted antigen, CD22 is targeted in therapies against dysregulated B cells that cause autoimmune diseases and blood cancers. Here we report the crystal structure of human CD22 at 2.1 Å resolution, which reveals that specificity for α2-6 sialic acid ligands is dictated by a pre-formed β-hairpin as a unique mode of recognition across sialic acid-binding immunoglobulin-type lectins. The CD22 ectodomain adopts an extended conformation that facilitates concomitant CD22 nanocluster formation on B cells and binding to trans ligands to avert autoimmunity in mammals. We structurally delineate the CD22 site targeted by the therapeutic antibody epratuzumab at 3.1 Å resolution and determine a critical role for CD22 N-linked glycosylation in antibody engagement. Our studies provide molecular insights into mechanisms governing B-cell inhibition and valuable clues for the design of immune modulators in B-cell dysfunction.The B-cell-specific co-receptor CD22 is a therapeutic target for depleting dysregulated B cells. Here the authors structurally characterize the ectodomain of CD22 and present its crystal structure with the bound therapeutic antibody epratuzumab, which gives insights into the mechanism of inhibition of B-cell activation.


    Organizational Affiliation

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




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
B-cell receptor CD22
A
324Homo sapiensMutation(s): 5 
Gene Names: CD22 (SIGLEC2)
Find proteins for P20273 (Homo sapiens)
Go to Gene View: CD22
Go to UniProtKB:  P20273
Small Molecules
Ligands 6 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
GOL
Query on GOL

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Download CCD File 
A
GLYCEROL
GLYCERIN; PROPANE-1,2,3-TRIOL
C3 H8 O3
PEDCQBHIVMGVHV-UHFFFAOYSA-N
 Ligand Interaction
MAN
Query on MAN

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Download CCD File 
A
ALPHA-D-MANNOSE
C6 H12 O6
WQZGKKKJIJFFOK-PQMKYFCFSA-N
 Ligand Interaction
GAL
Query on GAL

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Download CCD File 
A
BETA-D-GALACTOSE
C6 H12 O6
WQZGKKKJIJFFOK-FPRJBGLDSA-N
 Ligand Interaction
BMA
Query on BMA

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Download CCD File 
A
BETA-D-MANNOSE
C6 H12 O6
WQZGKKKJIJFFOK-RWOPYEJCSA-N
 Ligand Interaction
NAG
Query on NAG

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Download CCD File 
A
N-ACETYL-D-GLUCOSAMINE
C8 H15 N O6
OVRNDRQMDRJTHS-FMDGEEDCSA-N
 Ligand Interaction
SIA
Query on SIA

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Download CCD File 
A
O-SIALIC ACID
C11 H19 N O9
SQVRNKJHWKZAKO-YRMXFSIDSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.2 Å
  • R-Value Free: 0.254 
  • R-Value Work: 0.210 
  • Space Group: C 1 2 1
Unit Cell:
Length (Å)Angle (°)
a = 124.283α = 90.00
b = 57.912β = 106.99
c = 48.081γ = 90.00
Software Package:
Software NamePurpose
PDB_EXTRACTdata extraction
XSCALEdata scaling
PHENIXrefinement
PHASERphasing
XDSdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
CIHR, BantingCanada--

Revision History 

  • Version 1.0: 2017-10-04
    Type: Initial release
  • Version 1.1: 2017-10-25
    Type: Database references