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Open data
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Basic information
| Entry | Database: PDB / ID: 7k0c | |||||||||||||||||||||||||||||||||
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| Title | Structure of Secretory IgM Core | |||||||||||||||||||||||||||||||||
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Keywords | IMMUNE SYSTEM / Immunoglobulin M | |||||||||||||||||||||||||||||||||
| Function / homology | Function and homology informationhexameric IgM immunoglobulin complex / polymeric immunoglobulin receptor activity / immunoglobulin transcytosis in epithelial cells mediated by polymeric immunoglobulin receptor / polymeric immunoglobulin binding / IgM B cell receptor complex / dimeric IgA immunoglobulin complex / secretory dimeric IgA immunoglobulin complex / pentameric IgM immunoglobulin complex / monomeric IgA immunoglobulin complex / secretory IgA immunoglobulin complex ...hexameric IgM immunoglobulin complex / polymeric immunoglobulin receptor activity / immunoglobulin transcytosis in epithelial cells mediated by polymeric immunoglobulin receptor / polymeric immunoglobulin binding / IgM B cell receptor complex / dimeric IgA immunoglobulin complex / secretory dimeric IgA immunoglobulin complex / pentameric IgM immunoglobulin complex / monomeric IgA immunoglobulin complex / secretory IgA immunoglobulin complex / Fc receptor signaling pathway / IgA binding / pre-B cell allelic exclusion / IgM immunoglobulin complex / glomerular filtration / detection of chemical stimulus involved in sensory perception of bitter taste / CD22 mediated BCR regulation / immunoglobulin receptor binding / azurophil granule membrane / receptor clustering / positive regulation of respiratory burst / humoral immune response / Scavenging of heme from plasma / antigen binding / Antigen activates B Cell Receptor (BCR) leading to generation of second messengers / Cell surface interactions at the vascular wall / B cell receptor signaling pathway / epidermal growth factor receptor signaling pathway / antibacterial humoral response / transmembrane signaling receptor activity / protein-containing complex assembly / protein-macromolecule adaptor activity / defense response to Gram-negative bacterium / blood microparticle / Potential therapeutics for SARS / adaptive immune response / receptor complex / immune response / innate immune response / Neutrophil degranulation / cell surface / signal transduction / protein homodimerization activity / extracellular space / extracellular exosome / extracellular region / plasma membrane Similarity search - Function | |||||||||||||||||||||||||||||||||
| Biological species | Homo sapiens (human) | |||||||||||||||||||||||||||||||||
| Method | ELECTRON MICROSCOPY / single particle reconstruction / cryo EM / Resolution: 3.3 Å | |||||||||||||||||||||||||||||||||
Authors | Kumar, N. / Arthur, C.P. / Ciferri, C. / Matsumoto, M.L. | |||||||||||||||||||||||||||||||||
Citation | Journal: Structure / Year: 2021Title: Structure of the human secretory immunoglobulin M core. Authors: Nikit Kumar / Christopher P Arthur / Claudio Ciferri / Marissa L Matsumoto / ![]() Abstract: Immunoglobulins (Ig) A and M are the only human antibodies that form oligomers and undergo transcytosis to mucosal secretions via the polymeric Ig receptor (pIgR). When complexed with the J-chain (JC) ...Immunoglobulins (Ig) A and M are the only human antibodies that form oligomers and undergo transcytosis to mucosal secretions via the polymeric Ig receptor (pIgR). When complexed with the J-chain (JC) and the secretory component (SC) of pIgR, secretory IgA and IgM (sIgA and sIgM) play critical roles in host-pathogen defense. Recently, we determined the structure of sIgA-Fc which elucidated the mechanism of polymeric IgA assembly and revealed an extensive binding interface between IgA-Fc, JC, and SC. Despite low sequence identity shared with IgA-Fc, IgM-Fc also undergoes JC-mediated assembly and binds pIgR. Here, we report the structure of sIgM-Fc and carryout a systematic comparison to sIgA-Fc. Our structural analysis reveals a remarkably conserved mechanism of JC-templated oligomerization and SC recognition of both IgM and IgA through a highly conserved network of interactions. These studies reveal the structurally conserved features of sIgM and sIgA required for function in mucosal immunity. | |||||||||||||||||||||||||||||||||
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Structure visualization
| Movie |
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| Structure viewer | Molecule: Molmil Jmol/JSmol |
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Downloads & links
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Download
| PDBx/mmCIF format | 7k0c.cif.gz | 517.2 KB | Display | PDBx/mmCIF format |
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| PDB format | pdb7k0c.ent.gz | 416.2 KB | Display | PDB format |
| PDBx/mmJSON format | 7k0c.json.gz | Tree view | PDBx/mmJSON format | |
| Others | Other downloads |
-Validation report
| Summary document | 7k0c_validation.pdf.gz | 1.1 MB | Display | wwPDB validaton report |
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| Full document | 7k0c_full_validation.pdf.gz | 1.2 MB | Display | |
| Data in XML | 7k0c_validation.xml.gz | 94 KB | Display | |
| Data in CIF | 7k0c_validation.cif.gz | 142.4 KB | Display | |
| Arichive directory | https://data.pdbj.org/pub/pdb/validation_reports/k0/7k0c ftp://data.pdbj.org/pub/pdb/validation_reports/k0/7k0c | HTTPS FTP |
-Related structure data
| Related structure data | ![]() 22591MC M: map data used to model this data 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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| 1 |
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Components
| #1: Protein | Mass: 65154.094 Da / Num. of mol.: 1 Source method: isolated from a genetically manipulated source Source: (gene. exp.) Homo sapiens (human) / Gene: PIGR / Production host: ![]() | ||||||||
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| #2: Protein | Mass: 40677.605 Da / Num. of mol.: 10 Source method: isolated from a genetically manipulated source Source: (gene. exp.) Homo sapiens (human) / Gene: IGHM / Production host: ![]() #3: Protein | | Mass: 15611.458 Da / Num. of mol.: 1 Source method: isolated from a genetically manipulated source Source: (gene. exp.) Homo sapiens (human) / Gene: JCHAIN, IGCJ, IGJ / Production host: ![]() #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 Has ligand of interest | N | Has protein modification | Y | |
-Experimental details
-Experiment
| Experiment | Method: ELECTRON MICROSCOPY |
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| EM experiment | Aggregation state: PARTICLE / 3D reconstruction method: single particle reconstruction |
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Sample preparation
| Component | Name: Structure of the Human Secretory Immunoglobulin M Core Type: COMPLEX / Entity ID: #1-#3 / Source: RECOMBINANT | |||||||||||||||
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| Molecular weight | Value: 480 kDa/nm / Experimental value: NO | |||||||||||||||
| Source (natural) | Organism: Homo sapiens (human) | |||||||||||||||
| Source (recombinant) | Organism: ![]() | |||||||||||||||
| Buffer solution | pH: 7.2 | |||||||||||||||
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| Specimen | Conc.: 0.2 mg/ml / Embedding applied: NO / Shadowing applied: NO / Staining applied: NO / Vitrification applied: YES / Details: Sample was monodisperse. | |||||||||||||||
| Specimen support | Grid material: GOLD / Grid mesh size: 300 divisions/in. / Grid type: UltrAuFoil R0.6/1 | |||||||||||||||
| Vitrification | Instrument: FEI VITROBOT MARK IV / Cryogen name: ETHANE / Humidity: 100 % / Chamber temperature: 277 K Details: Blot for 3.5 seconds before plunging with blot force 7. |
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Electron microscopy imaging
| Experimental equipment | ![]() Model: Titan Krios / Image courtesy: FEI Company |
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| Microscopy | Model: FEI TITAN KRIOS |
| Electron gun | Electron source: FIELD EMISSION GUN / Accelerating voltage: 300 kV / Illumination mode: FLOOD BEAM |
| Electron lens | Mode: BRIGHT FIELD / Nominal magnification: 165000 X / Cs: 2.7 mm |
| Specimen holder | Cryogen: NITROGEN / Specimen holder model: FEI TITAN KRIOS AUTOGRID HOLDER |
| Image recording | Average exposure time: 0.2 sec. / Electron dose: 1.02 e/Å2 / Detector mode: COUNTING / Film or detector model: GATAN K2 SUMMIT (4k x 4k) |
| Image scans | Movie frames/image: 50 |
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Processing
| Software | Name: PHENIX / Version: 1.18.1_3865: / Classification: refinement | ||||||||||||||||||||||||
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| CTF correction | Type: PHASE FLIPPING AND AMPLITUDE CORRECTION | ||||||||||||||||||||||||
| Symmetry | Point symmetry: C1 (asymmetric) | ||||||||||||||||||||||||
| 3D reconstruction | Resolution: 3.3 Å / Resolution method: FSC 0.143 CUT-OFF / Num. of particles: 244123 / Symmetry type: POINT | ||||||||||||||||||||||||
| Refine LS restraints |
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About Yorodumi




Homo sapiens (human)
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UCSF Chimera






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