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Protein Structures and Oligomeric States

Enter a protein name, UniProt accession or PDB ID. Name searches ask you to confirm the protein identity before related structures are queried.

Current Protein Identity：P01833 New Search
16PDB entries
25Biological assembly
32chain/assembly records
Main Difference Dimensions in This Set
Different construct Different mutation/modification Different assembly state Different ligand/ion Different experimental method Different experimental conditions Different structure-quality metrics

Difference tags compare only the current result set; every original PDB and assembly record remains separate.

Related-Structure Differences

Each row represents one biological assembly in one PDB entry; multiple monomers of the same protein are listed separately.

PDB Entry Assembly / Oligomeric State Construct Mutations and Modifications Ligands, Ions and Non-polymers Experimental Method Experimental Conditions Structure Quality
1XED Crystal Structure of a Ligand-Binding Domain of the Human Polymeric Ig Receptor, pIgR Deposited 2004-09-10 Assembly 1 Protein monomer Monomer；Protein × 1 PDB declaration: monomeric（1） Consistent with protein count
Chain A 19–127（109 aa） Fragment：N-Terminal Domain I
Not recorded MG MAGNESIUM ION × 1 X-RAY DIFFRACTION
X-ray crystallization conditions pH 6.5；293 K；PEG 8000, Magnesium acetate, cacodylate, pH 6.5, VAPOR DIFFUSION, HANGING DROP, temperature 293K, pH 6.50
Resolution 1.90 Å R-free 0.244
1XED Crystal Structure of a Ligand-Binding Domain of the Human Polymeric Ig Receptor, pIgR Deposited 2004-09-10 Assembly 2 Protein monomer Monomer；Protein × 1 PDB declaration: monomeric（1） Consistent with protein count
Chain B 19–127（109 aa） Fragment：N-Terminal Domain I
Not recorded MG MAGNESIUM ION × 1 X-RAY DIFFRACTION
X-ray crystallization conditions pH 6.5；293 K；PEG 8000, Magnesium acetate, cacodylate, pH 6.5, VAPOR DIFFUSION, HANGING DROP, temperature 293K, pH 6.50
Resolution 1.90 Å R-free 0.244
1XED Crystal Structure of a Ligand-Binding Domain of the Human Polymeric Ig Receptor, pIgR Deposited 2004-09-10 Assembly 3 Protein monomer Monomer；Protein × 1 PDB declaration: monomeric（1） Consistent with protein count
Chain C 19–127（109 aa） Fragment：N-Terminal Domain I
Not recorded No recorded non-water small molecule X-RAY DIFFRACTION
X-ray crystallization conditions pH 6.5；293 K；PEG 8000, Magnesium acetate, cacodylate, pH 6.5, VAPOR DIFFUSION, HANGING DROP, temperature 293K, pH 6.50
Resolution 1.90 Å R-free 0.244
1XED Crystal Structure of a Ligand-Binding Domain of the Human Polymeric Ig Receptor, pIgR Deposited 2004-09-10 Assembly 4 Protein monomer Monomer；Protein × 1 PDB declaration: monomeric（1） Consistent with protein count
Chain D 19–127（109 aa） Fragment：N-Terminal Domain I
Not recorded No recorded non-water small molecule X-RAY DIFFRACTION
X-ray crystallization conditions pH 6.5；293 K；PEG 8000, Magnesium acetate, cacodylate, pH 6.5, VAPOR DIFFUSION, HANGING DROP, temperature 293K, pH 6.50
Resolution 1.90 Å R-free 0.244
1XED Crystal Structure of a Ligand-Binding Domain of the Human Polymeric Ig Receptor, pIgR Deposited 2004-09-10 Assembly 5 Protein monomer Monomer；Protein × 1 PDB declaration: monomeric（1） Consistent with protein count
Chain E 19–127（109 aa） Fragment：N-Terminal Domain I
Not recorded No recorded non-water small molecule X-RAY DIFFRACTION
X-ray crystallization conditions pH 6.5；293 K；PEG 8000, Magnesium acetate, cacodylate, pH 6.5, VAPOR DIFFUSION, HANGING DROP, temperature 293K, pH 6.50
Resolution 1.90 Å R-free 0.244
1XED Crystal Structure of a Ligand-Binding Domain of the Human Polymeric Ig Receptor, pIgR Deposited 2004-09-10 Assembly 6 Protein monomer Monomer；Protein × 1 PDB declaration: monomeric（1） Consistent with protein count
Chain F 19–127（109 aa） Fragment：N-Terminal Domain I
Not recorded No recorded non-water small molecule X-RAY DIFFRACTION
X-ray crystallization conditions pH 6.5；293 K；PEG 8000, Magnesium acetate, cacodylate, pH 6.5, VAPOR DIFFUSION, HANGING DROP, temperature 293K, pH 6.50
Resolution 1.90 Å R-free 0.244
1XED Crystal Structure of a Ligand-Binding Domain of the Human Polymeric Ig Receptor, pIgR Deposited 2004-09-10 Assembly 7 Protein homooligomer Homooligomer；Protein × 4 PDB declaration: tetrameric（4） Consistent with protein count
Chain A 19–127（109 aa） Fragment：N-Terminal Domain I
Chain B 19–127（109 aa） Fragment：N-Terminal Domain I
Chain C 19–127（109 aa） Fragment：N-Terminal Domain I
Chain D 19–127（109 aa） Fragment：N-Terminal Domain I
Not recorded MG MAGNESIUM ION × 2 X-RAY DIFFRACTION
X-ray crystallization conditions pH 6.5；293 K；PEG 8000, Magnesium acetate, cacodylate, pH 6.5, VAPOR DIFFUSION, HANGING DROP, temperature 293K, pH 6.50
Resolution 1.90 Å R-free 0.244
1XED Crystal Structure of a Ligand-Binding Domain of the Human Polymeric Ig Receptor, pIgR Deposited 2004-09-10 Assembly 8 Protein homooligomer Homooligomer；Protein × 2 PDB declaration: dimeric（2） Consistent with protein count
Chain B 19–127（109 aa） Fragment：N-Terminal Domain I
Chain D 19–127（109 aa） Fragment：N-Terminal Domain I
Not recorded MG MAGNESIUM ION × 1 X-RAY DIFFRACTION
X-ray crystallization conditions pH 6.5；293 K；PEG 8000, Magnesium acetate, cacodylate, pH 6.5, VAPOR DIFFUSION, HANGING DROP, temperature 293K, pH 6.50
Resolution 1.90 Å R-free 0.244
1XED Crystal Structure of a Ligand-Binding Domain of the Human Polymeric Ig Receptor, pIgR Deposited 2004-09-10 Assembly 9 Protein homooligomer Homooligomer；Protein × 2 PDB declaration: dimeric（2） Consistent with protein count
Chain A 19–127（109 aa） Fragment：N-Terminal Domain I
Chain C 19–127（109 aa） Fragment：N-Terminal Domain I
Not recorded MG MAGNESIUM ION × 1 X-RAY DIFFRACTION
X-ray crystallization conditions pH 6.5；293 K；PEG 8000, Magnesium acetate, cacodylate, pH 6.5, VAPOR DIFFUSION, HANGING DROP, temperature 293K, pH 6.50
Resolution 1.90 Å R-free 0.244
2OCW Solution structure of human secretory component Deposited 2006-12-21 Assembly 1 Protein monomer Monomer；Protein × 1 PDB declaration: monomeric（1） Consistent with protein count
Chain A 19–603（585 aa）
Not recorded No recorded non-water small molecule SOLUTION SCATTERING mmCIF provides none of the parsed conditions Resolution not provided
3CHN Solution structure of human secretory IgA1 Deposited 2008-03-10 Assembly 1 Protein heterocomplex Heteromer；Protein × 10 PDB declaration: decameric（10） Consistent with protein count
Chain J 353–458（106 aa） Fragment：Ig-like V-type domain 4
Chain S 19–603（585 aa）
Not recorded No recorded non-water small molecule SOLUTION SCATTERING mmCIF provides none of the parsed conditions Resolution not provided
3CM9 Solution Structure of Human SIgA2 Deposited 2008-03-21 Assembly 1 Protein heterocomplex Heteromer；Protein × 10 PDB declaration: decameric（10） Consistent with protein count
Chain J 353–458（106 aa） Fragment：Ig-like V-type domain 4
Chain S 19–603（585 aa）
Not recorded No recorded non-water small molecule SOLUTION SCATTERING mmCIF provides none of the parsed conditions Resolution not provided
5D4K Crystal structure of the human polymeric Ig receptor (pIgR) ectodomain Deposited 2015-08-07 Assembly 1 Other combination Monomer；Protein × 1 PDB declaration: monomeric（1） Consistent with protein count
Chain A 19–565（547 aa） Fragment：ectodomain (UNP residues 19-565)
Not recorded NAG 2-acetamido-2-deoxy-beta-D-glucopyranose × 3 SO4 SULFATE ION × 2 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, SITTING DROP；pH 5.5；295 K；0.2 M ammonium sulfate, 0.1M BisTris pH 5.5, 31% Polyethylene glycol 3350
Resolution 2.60 Å R-free 0.254
5D4K Crystal structure of the human polymeric Ig receptor (pIgR) ectodomain Deposited 2015-08-07 Assembly 2 Other combination Monomer；Protein × 1 PDB declaration: monomeric（1） Consistent with protein count
Chain B 19–565（547 aa） Fragment：ectodomain (UNP residues 19-565)
Not recorded NAG 2-acetamido-2-deoxy-beta-D-glucopyranose × 3 SO4 SULFATE ION × 2 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, SITTING DROP；pH 5.5；295 K；0.2 M ammonium sulfate, 0.1M BisTris pH 5.5, 31% Polyethylene glycol 3350
Resolution 2.60 Å R-free 0.254
6KXS Cryo-EM structure of human IgM-Fc in complex with the J chain and the ectodomain of pIgR Deposited 2019-09-12 Assembly 1 Other combination Heteromer；Protein × 12 PDB declaration: dodecameric（12） Consistent with protein count
Chain P 19–565（547 aa）
Not recorded NAG 2-acetamido-2-deoxy-beta-D-glucopyranose × 10 ELECTRON MICROSCOPY
cryo-EM buffer pH 7.4
cryo-EM vitrification conditions Cryogen ETHANE
Resolution 3.40 Å
6LX3 Cryo-EM structure of human secretory immunoglobulin A Deposited 2020-02-10 Assembly 1 Insufficient information Heteromer；Protein × 6 PDB declaration: hexameric（6） Consistent with protein count
Chain P 1–565（565 aa）
Not recorded No recorded non-water small molecule ELECTRON MICROSCOPY
cryo-EM buffer pH 7.4
cryo-EM vitrification conditions Cryogen ETHANE
Resolution 3.15 Å
6LXW Cryo-EM structure of human secretory immunoglobulin A in complex with the N-terminal domain of SpsA Deposited 2020-02-12 Assembly 1 Insufficient information Heteromer；Protein × 7 PDB declaration: heptameric（7） Consistent with protein count
Chain P 1–565（565 aa）
Not recorded No recorded non-water small molecule ELECTRON MICROSCOPY
cryo-EM buffer pH 7.4
cryo-EM vitrification conditions Cryogen ETHANE
Resolution 3.27 Å
6UE7 Structure of dimeric sIgA complex Deposited 2019-09-20 Assembly 1 Other combination Heteromer；Protein × 6 PDB declaration: hexameric（6） Consistent with protein count
Chain C 19–603（585 aa） Fragment：UNP residues 19-603
Not recorded NAG 2-acetamido-2-deoxy-beta-D-glucopyranose × 7 ELECTRON MICROSCOPY
cryo-EM buffer pH 7.2
cryo-EM vitrification conditions Cryogen ETHANE
Resolution 2.90 Å
6UE8 Structure of tetrameric sIgA complex (Class 1) Deposited 2019-09-20 Assembly 1 Other combination Heteromer；Protein × 10 PDB declaration: decameric（10） Consistent with protein count
Chain C 19–603（585 aa） Fragment：UNP residues 19-603
Not recorded NAG 2-acetamido-2-deoxy-beta-D-glucopyranose × 5 ELECTRON MICROSCOPY
cryo-EM buffer pH 7.2
cryo-EM vitrification conditions Cryogen ETHANE
Resolution 3.00 Å
6UE9 Structure of tetrameric sIgA complex (Class 2) Deposited 2019-09-20 Assembly 1 Other combination Heteromer；Protein × 10 PDB declaration: decameric（10） Consistent with protein count
Chain C 19–603（585 aa） Fragment：UNP residues 19-603
Not recorded NAG 2-acetamido-2-deoxy-beta-D-glucopyranose × 7 ELECTRON MICROSCOPY
cryo-EM buffer pH 7.2
cryo-EM vitrification conditions Cryogen ETHANE
Resolution 2.90 Å
6UEA Structure of pentameric sIgA complex Deposited 2019-09-20 Assembly 1 Other combination Heteromer；Protein × 12 PDB declaration: dodecameric（12） Consistent with protein count
Chain C 19–603（585 aa） Fragment：UNP residues 19-603
Not recorded NAG 2-acetamido-2-deoxy-beta-D-glucopyranose × 2 ELECTRON MICROSCOPY
cryo-EM buffer pH 7.2
cryo-EM vitrification conditions Cryogen ETHANE
Resolution 3.00 Å
7K0C Structure of Secretory IgM Core Deposited 2020-09-04 Assembly 1 Other combination Heteromer；Protein × 12 PDB declaration: dodecameric（12） Consistent with protein count
Chain C 19–603（585 aa）
Not recorded No recorded non-water small molecule ELECTRON MICROSCOPY
cryo-EM buffer pH 7.2
cryo-EM vitrification conditions Cryogen ETHANE；Blot for 3.5 seconds before plunging with blot force 7.
Resolution 3.30 Å
7YSG Cryo-EM structure of human FcmR bound to sIgM Deposited 2022-08-12 Assembly 1 Other combination Heteromer；Protein × 16 PDB declaration: hexadecameric（16） Consistent with protein count
Chain P 19–559（541 aa）
Not recorded NAG 2-acetamido-2-deoxy-beta-D-glucopyranose × 10 ELECTRON MICROSCOPY
cryo-EM buffer pH 7.4
cryo-EM vitrification conditions Cryogen ETHANE
Resolution 3.18 Å
8SKU Structure of human SIgA1 in complex with human CD89 (FcaR1) Deposited 2023-04-20 Assembly 1 Other combination Heteromer；Protein × 8 PDB declaration: octameric（8） Consistent with protein count
Chain E 19–565（547 aa）
Not recorded NAG 2-acetamido-2-deoxy-beta-D-glucopyranose × 4 ELECTRON MICROSCOPY
cryo-EM buffer pH 7
cryo-EM vitrification conditions Cryogen ETHANE
Resolution 3.20 Å
8SKV Structure of human SIgA1 in complex with Streptococcus pyogenes protein M4 (Arp4) Deposited 2023-04-20 Assembly 1 Other combination Heteromer；Protein × 8 PDB declaration: octameric（8） Consistent with protein count
Chain E 19–565（547 aa）
Not recorded NAG 2-acetamido-2-deoxy-beta-D-glucopyranose × 7 ELECTRON MICROSCOPY
cryo-EM buffer pH 7
cryo-EM vitrification conditions Cryogen ETHANE
Resolution 3.10 Å

This page presents structural evidence recorded in PDB/mmCIF.“No recorded non-water small molecule” does not prove that the experimental sample was ligand-free; experimental conditions belong to the PDB experiment, while ligands and copy counts are shown for each biological assembly.