← Back to search

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：P01876 New Search
15PDB entries
18Biological assembly
50chain/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
1IGA MODEL OF HUMAN IGA1 DETERMINED BY SOLUTION SCATTERING CURVE-FITTING AND HOMOLOGY MODELLING Deposited 1998-12-23 Assembly 1 Protein heterocomplex Heteromer；Protein × 4 PDB declaration: tetrameric（4） Consistent with protein count
Chain A 1–353（353 aa） Fragment：CHAINS A AND B, HEAVY, CHAINS C AND D, LIGHT
Chain B 1–353（353 aa） Fragment：CHAINS A AND B, HEAVY, CHAINS C AND D, LIGHT
Not recorded No recorded non-water small molecule SOLUTION SCATTERING mmCIF provides none of the parsed conditions Resolution not provided
1OW0 Crystal structure of human FcaRI bound to IgA1-Fc Deposited 2003-03-27 Assembly 1 Other combination Homooligomer；Protein × 2 PDB declaration: dimeric（2） Consistent with protein count
Chain A 122–335（214 aa） Fragment：Fc region
Chain B 122–335（214 aa） Fragment：Fc region
Not recorded No recorded non-water small molecule X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, HANGING DROP；pH 6.5；296 K；magnesium sulfate heptahydrate, MES, pH 6.5, VAPOR DIFFUSION, HANGING DROP, temperature 296K
Resolution 3.10 Å R-free 0.284
1OW0 Crystal structure of human FcaRI bound to IgA1-Fc Deposited 2003-03-27 Assembly 4 Other combination Heteromer；Protein × 4 PDB declaration: tetrameric（4） Consistent with protein count
Chain A 122–335（214 aa） Fragment：Fc region
Chain B 122–335（214 aa） Fragment：Fc region
Not recorded NAG 2-acetamido-2-deoxy-beta-D-glucopyranose × 2 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, HANGING DROP；pH 6.5；296 K；magnesium sulfate heptahydrate, MES, pH 6.5, VAPOR DIFFUSION, HANGING DROP, temperature 296K
Resolution 3.10 Å R-free 0.284
2QEJ Crystal structure of a Staphylococcus aureus protein (SSL7) in complex with Fc of human IgA1 Deposited 2007-06-26 Assembly 1 Other combination Heteromer；Protein × 4 PDB declaration: pentameric（5） Review required
Chain A 123–336（214 aa） Fragment：FC REGION
Chain B 123–336（214 aa） Fragment：FC REGION
Not recorded GOL GLYCEROL × 5 CA CALCIUM ION × 1 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION；pH 6.5；291 K；12% PEG 8000, 66 mM sodium cacodylate pH 6.5, 130 mM calcium acetate, VAPOR DIFFUSION, temperature 291K
Resolution 3.20 Å R-free 0.312
2QTJ Solution structure of human dimeric immunoglobulin A Deposited 2007-08-02 Assembly 1 Protein heterocomplex Heteromer；Protein × 4 PDB declaration: tetrameric（4） Consistent with protein count
Chain A 1–475（475 aa）
Chain B 1–475（475 aa）
Not recorded No recorded non-water small molecule SOLUTION SCATTERING mmCIF provides none of the parsed conditions Resolution not provided
2QTJ Solution structure of human dimeric immunoglobulin A Deposited 2007-08-02 Assembly 2 Protein heterocomplex Heteromer；Protein × 4 PDB declaration: tetrameric（4） Consistent with protein count
Chain C 1–475（475 aa）
Chain D 1–475（475 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 A 1–353（353 aa）
Chain B 1–353（353 aa）
Chain C 1–353（353 aa）
Chain D 1–353（353 aa）
Not recorded No recorded non-water small molecule SOLUTION SCATTERING mmCIF provides none of the parsed conditions Resolution not provided
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 A 122–353（232 aa）
Chain B 122–353（232 aa）
Chain C 122–353（232 aa）
Chain D 122–353（232 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 A 122–353（232 aa）
Chain B 122–353（232 aa）
Chain C 122–353（232 aa）
Chain D 122–353（232 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 A 123–353（231 aa） Fragment：UNP residues 123-353
Chain B 123–353（231 aa） Fragment：UNP residues 123-353
Chain F 123–353（231 aa） Fragment：UNP residues 123-353
Chain G 123–353（231 aa） Fragment：UNP residues 123-353
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
6XJA Streptococcus Pneumoniae IgA1 Protease with IgA1 substrate Deposited 2020-06-23 Assembly 1 Protein heterocomplex Heteromer；Protein × 5 PDB declaration: pentameric（5） Consistent with protein count
Chain A 122–331（210 aa）
Chain B 122–331（210 aa）
Not recorded No recorded non-water small molecule ELECTRON MICROSCOPY
cryo-EM buffer pH 7；20 mM Hepes, pH 7 150 mM NaCl
cryo-EM vitrification conditions Cryogen ETHANE
Resolution 4.00 Å
7UVL IgA1 Protease with IgA1 substrate Deposited 2022-05-02 Assembly 1 Protein heterocomplex Heteromer；Protein × 5 PDB declaration: pentameric（5） Consistent with protein count
Chain A 123–331（209 aa）
Chain B 123–331（209 aa）
Not recorded No recorded non-water small molecule ELECTRON MICROSCOPY
cryo-EM buffer pH 7.4
cryo-EM vitrification conditions Cryogen ETHANE
Resolution 3.56 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 A 1–353（353 aa）
Chain B 1–353（353 aa）
Chain C 1–353（353 aa）
Chain D 1–353（353 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 A 1–353（353 aa）
Chain B 1–353（353 aa）
Chain C 1–353（353 aa）
Chain D 1–353（353 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
9MBZ Cryo-EM structure of human FcRL4 bound to IgA-Fc/J Deposited 2025-03-17 Assembly 1 Insufficient information Heteromer；Protein × 6 PDB declaration: hexameric（6） Consistent with protein count
Chain A 122–353（232 aa）
Chain B 122–353（232 aa）
Chain C 122–353（232 aa）
Chain D 122–353（232 aa）
Not recorded No recorded non-water small molecule ELECTRON MICROSCOPY mmCIF provides none of the parsed conditions Resolution 3.30 Å
9OFR CRYSTAL STRUCTURE OF THE HUMAN IGA1 FC FRAGMENT-FC-ALPHA RECEPTOR (CD89) COMPLEX Deposited 2025-04-30 Assembly 1 Other combination Heteromer；Protein × 4 PDB declaration: tetrameric（4） Consistent with protein count
Chain A 123–335（213 aa） Fragment：FC fragment, UNP residues 123-335
Chain B 123–335（213 aa） Fragment：FC fragment, UNP residues 123-335
Not recorded NAG 2-acetamido-2-deoxy-beta-D-glucopyranose × 7 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, HANGING DROP；pH 8；294 K；0.15M sodium chloride 0.1M Tris-HCl pH 8.0 8% PEG 6000
Resolution 2.65 Å R-free 0.264
9OFR CRYSTAL STRUCTURE OF THE HUMAN IGA1 FC FRAGMENT-FC-ALPHA RECEPTOR (CD89) COMPLEX Deposited 2025-04-30 Assembly 2 Protein heterocomplex Heteromer；Protein × 4 PDB declaration: tetrameric（4） Consistent with protein count
Chain E 123–335（213 aa） Fragment：FC fragment, UNP residues 123-335
Chain G 123–335（213 aa） Fragment：FC fragment, UNP residues 123-335
Not recorded NAG 2-acetamido-2-deoxy-beta-D-glucopyranose × 7 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, HANGING DROP；pH 8；294 K；0.15M sodium chloride 0.1M Tris-HCl pH 8.0 8% PEG 6000
Resolution 2.65 Å R-free 0.264
9R2E Structure of ARGX-121 Fab fragment in complex with the Fc fragment of IgA1 Deposited 2025-04-30 Assembly 1 Protein heterocomplex Heteromer；Protein × 6 PDB declaration: hexameric（6） Consistent with protein count
Chain P 123–335（213 aa）
Chain Q 123–335（213 aa）
Not recorded EDO 1,2-ETHANEDIOL × 4 PEG DI(HYDROXYETHYL)ETHER × 5 MG MAGNESIUM ION × 3 X-RAY DIFFRACTION
X-ray crystallization conditions VAPOR DIFFUSION, SITTING DROP；277 K；16% (w/v) PEG8000, 20% (v/v) Glycerol, 0.16 M MgAcetate, 0.08 M Na Cacodylate pH 6.50
Resolution 2.54 Å R-free 0.252

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.