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Open data
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Basic information
| Entry | Database: PDB / ID: 5vkj | |||||||||
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| Title | Crystal structure of human CD22 Ig domains 1-3 | |||||||||
Components | B-cell receptor CD22 | |||||||||
Keywords | IMMUNE SYSTEM / Siglec / Sialic acid / carbohydrate binding protein | |||||||||
| Function / homology | Function and homology informationregulation 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 / regulation of endocytosis ...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 / regulation of endocytosis / B cell activation / 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 / membrane / plasma membrane / cytoplasm Similarity search - Function | |||||||||
| Biological species | Homo sapiens (human) | |||||||||
| Method | X-RAY DIFFRACTION / SYNCHROTRON / MOLECULAR REPLACEMENT / Resolution: 2.12 Å | |||||||||
Authors | Julien, J.P. / Ereno-Orbea, J. / Sicard, T. | |||||||||
| Funding support | Canada, 1items
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Citation | Journal: Nat Commun / Year: 2017Title: 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. | |||||||||
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Structure visualization
| Structure viewer | Molecule: Molmil Jmol/JSmol |
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Downloads & links
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Download
| PDBx/mmCIF format | 5vkj.cif.gz | 84.6 KB | Display | PDBx/mmCIF format |
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| PDB format | pdb5vkj.ent.gz | 60.5 KB | Display | PDB format |
| PDBx/mmJSON format | 5vkj.json.gz | Tree view | PDBx/mmJSON format | |
| Others | Other downloads |
-Validation report
| Arichive directory | https://data.pdbj.org/pub/pdb/validation_reports/vk/5vkj ftp://data.pdbj.org/pub/pdb/validation_reports/vk/5vkj | HTTPS FTP |
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-Related structure data
| Related structure data | ![]() 8704C ![]() 8705C ![]() 5vkkC ![]() 5vkmC ![]() 5vl3C 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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| Unit cell |
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| Components on special symmetry positions |
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| Details | Monomer as determined by gel filtration |
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Components
| #1: Protein | Mass: 36660.293 Da / Num. of mol.: 1 / Fragment: Extracellular domain residues 20-330 / Mutation: N67A,N112A,N135A,N164A,N231A Source method: isolated from a genetically manipulated source Source: (gene. exp.) Homo sapiens (human) / Gene: CD22, SIGLEC2 / Cell line (production host): HEK293 / Production host: Homo sapiens (human) / References: UniProt: P20273 | ||||
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| #2: 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 | ||||
| #3: Chemical | ChemComp-GOL / #4: Water | ChemComp-HOH / | Has protein modification | Y | |
-Experimental details
-Experiment
| Experiment | Method: X-RAY DIFFRACTION / Number of used crystals: 1 |
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Sample preparation
| Crystal | Density Matthews: 2.26 Å3/Da / Density % sol: 45.63 % |
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| Crystal grow | Temperature: 293 K / Method: vapor diffusion Details: 30% PEG 4000, 0.2 M lithium chloride and 0.1 M Tris pH 8.5 |
-Data collection
| Diffraction | Mean temperature: 100 K |
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| Diffraction source | Source: SYNCHROTRON / Site: CLSI / Beamline: 08ID-1 / Wavelength: 0.97949 Å |
| Detector | Type: RAYONIX MX-300 / Detector: CCD / Date: Sep 13, 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: 2.12→46.242 Å / Num. obs: 18725 / % possible obs: 99.8 % / Redundancy: 3.8 % / CC1/2: 0.999 / Rmerge(I) obs: 0.063 / Net I/σ(I): 15.8 |
| Reflection shell | Resolution: 2.12→2.2 Å / Redundancy: 3.8 % / Rmerge(I) obs: 0.4571 / Mean I/σ(I) obs: 2.3 / Num. unique obs: 1848 / CC1/2: 0.801 / Rpim(I) all: 0.229 / % possible all: 99.8 |
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Processing
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| Refinement | Method to determine structure: MOLECULAR REPLACEMENTStarting model: Crystal structure from a different crystal obtained with this construct by MAD phasing with heavy atom Resolution: 2.12→46.242 Å / SU ML: 0.27 / Cross valid method: FREE R-VALUE / σ(F): 1.34 / Phase error: 25.99 / Stereochemistry target values: ML
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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: 2.12→46.242 Å
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| LS refinement shell |
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About Yorodumi




Homo sapiens (human)
X-RAY DIFFRACTION
Canada, 1items
Citation
















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