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Open data
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Basic information
Entry | Database: PDB / ID: 5vl3 | ||||||||||||
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Title | CD22 d1-d3 in complex with therapeutic Fab Epratuzumab | ||||||||||||
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![]() | IMMUNE SYSTEM / therapeutic antibody / Siglec / B cell / Fab | ||||||||||||
Function / homology | ![]() regulation of B cell proliferation / IgM binding / negative regulation of immunoglobulin production / negative regulation of B cell receptor signaling pathway / sialic acid binding / CD22 mediated BCR regulation / negative regulation of calcium-mediated signaling / CD4 receptor binding / neuronal cell body membrane / B cell activation ...regulation of B cell proliferation / IgM binding / negative regulation of immunoglobulin production / negative regulation of B cell receptor signaling pathway / sialic acid binding / CD22 mediated BCR regulation / negative regulation of calcium-mediated signaling / CD4 receptor binding / neuronal cell body membrane / B cell activation / regulation of endocytosis / regulation of immune response / Antigen activates B Cell Receptor (BCR) leading to generation of second messengers / recycling endosome / Immunoregulatory interactions between a Lymphoid and a non-Lymphoid cell / carbohydrate binding / protein phosphatase binding / early endosome / cell adhesion / signaling receptor binding / external side of plasma membrane / cell surface / extracellular exosome / extracellular region / metal ion binding / membrane / plasma membrane / cytoplasm Similarity search - Function | ||||||||||||
Biological species | ![]() ![]() ![]() | ||||||||||||
Method | ![]() ![]() ![]() | ||||||||||||
![]() | Sicard, T. / Ereno-Orbea, J. / Julien, J.P. | ||||||||||||
Funding support | ![]()
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![]() | ![]() Title: Molecular basis of human CD22 function and therapeutic targeting. Authors: June Ereño-Orbea / Taylor Sicard / Hong Cui / Mohammad T Mazhab-Jafari / Samir Benlekbir / Alba Guarné / John L Rubinstein / Jean-Philippe Julien / ![]() 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 ...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. | ||||||||||||
History |
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Structure visualization
Structure viewer | Molecule: ![]() ![]() |
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Downloads & links
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Download
PDBx/mmCIF format | ![]() | 1.1 MB | Display | ![]() |
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PDB format | ![]() | 949.6 KB | Display | ![]() |
PDBx/mmJSON format | ![]() | Tree view | ![]() | |
Others | ![]() |
-Validation report
Summary document | ![]() | 1.1 MB | Display | ![]() |
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Full document | ![]() | 1.1 MB | Display | |
Data in XML | ![]() | 110.5 KB | Display | |
Data in CIF | ![]() | 139.7 KB | Display | |
Arichive directory | ![]() ![]() | HTTPS FTP |
-Related structure data
Related structure data | ![]() 8704C ![]() 8705C ![]() 5vkjC ![]() 5vkkC ![]() 5vkmC C: citing same article ( |
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Similar structure data | |
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Links
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Assembly
Deposited unit | ![]()
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2 | ![]()
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3 | ![]()
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4 | ![]()
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Unit cell |
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Components
-Antibody , 2 types, 8 molecules ACEHBDFL
#2: Antibody | Mass: 24028.684 Da / Num. of mol.: 4 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() ![]() Production host: ![]() #3: Antibody | Mass: 24340.979 Da / Num. of mol.: 4 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() ![]() Production host: ![]() |
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-Protein / Non-polymers , 2 types, 5 molecules QRST

#1: Protein | Mass: 36802.406 Da / Num. of mol.: 4 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() #8: Chemical | ChemComp-GOL / | |
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-Sugars , 4 types, 8 molecules
#4: Polysaccharide | 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose Source method: isolated from a genetically manipulated source #5: Polysaccharide | alpha-D-mannopyranose-(1-3)-[alpha-D-mannopyranose-(1-6)]beta-D-mannopyranose-(1-4)-2-acetamido-2- ...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-glucopyranose | Source method: isolated from a genetically manipulated source #6: Polysaccharide | Source method: isolated from a genetically manipulated source #7: Polysaccharide | beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta- ...beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose | Source method: isolated from a genetically manipulated source |
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-Details
Has protein modification | Y |
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-Experimental details
-Experiment
Experiment | Method: ![]() |
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Sample preparation
Crystal | Density Matthews: 2.99 Å3/Da / Density % sol: 58.84 % |
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Crystal grow | Temperature: 293 K / Method: vapor diffusion / Details: 20 mM Tris pH 8.0 and 150 mM NaCl, 5mg/mL |
-Data collection
Diffraction | Mean temperature: 100 K |
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Diffraction source | Source: ![]() ![]() ![]() |
Detector | Type: RAYONIX MX-300 / Detector: CCD / Date: Dec 1, 2016 |
Radiation | Protocol: SINGLE WAVELENGTH / Monochromatic (M) / Laue (L): M / Scattering type: x-ray |
Radiation wavelength | Wavelength: 0.97949 Å / Relative weight: 1 |
Reflection | Resolution: 3.1→39.345 Å / Num. obs: 65863 / % possible obs: 94.2 % / Redundancy: 1.9 % / Biso Wilson estimate: 65.68 Å2 / CC1/2: 0.987 / Rmerge(I) obs: 0.09 / Rpim(I) all: 0.09 / Net I/σ(I): 8.2 |
Reflection shell | Resolution: 3.1→3.2 Å / Redundancy: 1.9 % / Rmerge(I) obs: 0.39 / Mean I/σ(I) obs: 1.9 / CC1/2: 0.74 / Rpim(I) all: 0.39 / % possible all: 96.7 |
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Processing
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Refinement | Method to determine structure: ![]()
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Solvent computation | Shrinkage radii: 0.9 Å / VDW probe radii: 1.11 Å / Solvent model: FLAT BULK SOLVENT MODEL | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Refinement step | Cycle: LAST / Resolution: 3.1→39.345 Å
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Refine LS restraints |
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LS refinement shell |
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