2ESG | pdb_00002esg

Solution structure of the complex between immunoglobulin IgA1 and human serum albumin

External Resource: Annotation

Domain Annotation: SCOP/SCOPe Classification
Domain Annotation: SCOP2 Classification
Domain Annotation: ECOD Classification
IMGT Antibody Annotation
SAbDab Antibody Annotation
Protein Family Annotation
Gene Ontology: Gene Product Annotation
InterPro: Protein Family Classification
Pharos: Disease Associations

Domain Annotation: SCOP/SCOPe Classification SCOP-e Database Homepage

Chains	Domain Info	Class	Fold	Superfamily	Family	Domain	Species	Provenance Source (Version)
E [auth C]	d2esgc1	All alpha proteins	Serum albumin-like	Serum albumin-like	Serum albumin-like	Serum albumin	human (Homo sapiens ) [TaxId: 9606 ],	SCOPe (2.08)

Domain Annotation: SCOP2 Classification SCOP2 Database Homepage

Chains	Type	Family Name	Domain Identifier	Family Identifier	Provenance Source (Version)
E [auth C]	SCOP2B Superfamily	Serum albumin-like	8033044	3001552	SCOP2B (2022-06-29)
E [auth C]	SCOP2B Superfamily	Serum albumin-like	8033047	3001552	SCOP2B (2022-06-29)
E [auth C]	SCOP2B Superfamily	Serum albumin-like	8033045	3001552	SCOP2B (2022-06-29)

Domain Annotation: ECOD Classification ECOD Database Homepage

Chains	Family Name	Domain Identifier	Architecture	Possible Homology	Homology	Topology	Family	Provenance Source (Version)
E [auth C]	Ion_trans_2	e2esgC1	A: alpha bundles	X: EGF-like	H: Rpp14/Pop5-like	T: Rpp14/Pop5-like	F: Ion_trans_2	ECOD (develop294)
E [auth C]	MATH_2	e2esgC3	A: alpha bundles	X: HTH	H: Nudix	T: winged helix domain	F: MATH_2	ECOD (develop294)
C [auth A]	MATH_2	e2esgA1	A: alpha bundles	X: HTH	H: Nudix	T: winged helix domain	F: MATH_2	ECOD (develop294)
D [auth B]	MATH_2	e2esgB1	A: alpha bundles	X: HTH	H: Nudix	T: winged helix domain	F: MATH_2	ECOD (develop294)
A [auth L]	MATH_2	e2esgL1	A: alpha bundles	X: HTH	H: Nudix	T: winged helix domain	F: MATH_2	ECOD (develop294)
B [auth M]	MATH_2	e2esgM1	A: alpha bundles	X: HTH	H: Nudix	T: winged helix domain	F: MATH_2	ECOD (develop294)

IMGT Antibody Annotation IMGT Database Homepage

Chain	Protein Name	Description	Organism Name	Gene Allele Name(s)	Domain Name(s)	Receptor Type	Receptor Description	Provenance Source
C [auth A], D [auth B]	IgA1	H-ALPHA-1	Homo sapiens (human)	IGHV1-301, IGHJ401, IGHJ402, IGHJ403, IGHA1*01	V-DOMAIN VH, C-DOMAIN CH1, C-DOMAIN CH2, C-DOMAIN CH3	IG	IG-ALPHA-1_KAPPA	IMGT (202610-0)
A [auth L], B [auth M]	IgA1	L-KAPPA	Homo sapiens (human)	IGKV1-1302, IGKV1D-1302, IGKJ401, IGKJ402, IGKC*01	V-DOMAIN V-KAPPA, C-DOMAIN C-KAPPA	IG	IG-ALPHA-1_KAPPA	IMGT (202610-0)

SAbDab Antibody Annotation SAbDab Database Homepage

Chain	Chain Class	Chain Subclass	Chain Type	Antigen Name(s)	Provenance Source
C [auth A], D [auth B]	Heavy Chain	IGHV1	-	-	SAbDab (2026-03-20)
A [auth L], B [auth M]	Light Chain	IGKV1	Kappa	-	SAbDab (2026-03-20)

Protein Family Annotation Pfam Database Homepage

Chains	Accession	Name	Description	Comments	Source
E [auth C]	PF00273	Serum albumin family (Serum_albumin)	Serum albumin family		Domain
C [auth A], D [auth B]	PF07654	Immunoglobulin C1-set domain (C1-set)	Immunoglobulin C1-set domain		Domain
C [auth A], D [auth B]	PF00047	Immunoglobulin domain (ig)	Immunoglobulin domain	Members of the immunoglobulin superfamily are found in hundreds of proteins of different functions. Examples include antibodies, the giant muscle kinase titin and receptor tyrosine kinases. Immunoglobulin-like domains may be involved in protein-prote ...	Members of the immunoglobulin superfamily are found in hundreds of proteins of different functions. Examples include antibodies, the giant muscle kinase titin and receptor tyrosine kinases. Immunoglobulin-like domains may be involved in protein-protein and protein-ligand interactions.	Domain

Gene Ontology: Gene Product Annotation Gene Ontology Database Homepage

Chains	Polymer	Molecular Function	Biological Process	Cellular Component
E [auth C]	Serum albumin	antioxidant activity vitamin binding vitamin B6 binding pyridoxal phosphate binding ion binding binding anion binding heterocyclic compound binding small molecule binding fatty acid binding organic acid binding lipid binding carboxylic acid binding monocarboxylic acid binding antioxidant activity vitamin binding vitamin B6 binding pyridoxal phosphate binding ion binding binding anion binding heterocyclic compound binding small molecule binding fatty acid binding organic acid binding lipid binding carboxylic acid binding monocarboxylic acid binding protein binding exogenous protein binding cation binding transition metal ion binding copper ion binding metal ion binding toxic substance binding macrolide binding enterobactin binding protein-folding chaperone binding DNA binding nucleic acid binding molecular carrier activity identical protein binding	regulation of biological process regulation of cellular process regulation of mitochondrial depolarization negative regulation of membrane depolarization biological regulation negative regulation of biological process mitochondrial depolarization regulation of membrane depolarization regulation of mitochondrial membrane potential membrane depolarization cellular process regulation of biological quality negative regulation of mitochondrial depolarization regulation of membrane potential regulation of biological process regulation of cellular process regulation of mitochondrial depolarization negative regulation of membrane depolarization biological regulation negative regulation of biological process mitochondrial depolarization regulation of membrane depolarization regulation of mitochondrial membrane potential membrane depolarization cellular process regulation of biological quality negative regulation of mitochondrial depolarization regulation of membrane potential cellular response to stimulus cellular response to nutrient levels response to nutrient levels response to stimulus cellular response to stress response to stress response to starvation cellular response to calcium ion starvation cellular response to starvation organic acid transport localization bilirubin transport organic anion transport nitrogen compound transport carboxylic acid transport transport dicarboxylic acid transport establishment of localization	extracellular exosome membrane-bounded organelle extracellular vesicle cellular anatomical structure extracellular organelle extracellular region organelle extracellular space vesicle extracellular membrane-bounded organelle protein-containing complex blood microparticle intracellular organelle intracellular anatomical structure extracellular exosome membrane-bounded organelle extracellular vesicle cellular anatomical structure extracellular organelle extracellular region organelle extracellular space vesicle extracellular membrane-bounded organelle protein-containing complex blood microparticle intracellular organelle intracellular anatomical structure Golgi apparatus cytoplasm intracellular membrane-bounded organelle endomembrane system membrane-enclosed lumen intracellular organelle lumen endoplasmic reticulum lumen organelle lumen endoplasmic reticulum vesicle lumen intracellular vesicle cytoplasmic vesicle lumen secretory granule lumen cytoplasmic vesicle secretory granule secretory vesicle platelet alpha granule platelet alpha granule lumen nucleus
C [auth A], D [auth B]	Immunoglobulin A1 heavy chain	binding antigen binding	cellular response to stimulus immune response-regulating cell surface receptor signaling pathway regulation of cellular process response to stimulus signaling positive regulation of biological process cell communication positive regulation of response to stimulus immune response-activating signaling pathway immune response-regulating signaling pathway positive regulation of immune response regulation of immune system process signal transduction positive regulation of immune system process cellular response to stimulus immune response-regulating cell surface receptor signaling pathway regulation of cellular process response to stimulus signaling positive regulation of biological process cell communication positive regulation of response to stimulus immune response-activating signaling pathway immune response-regulating signaling pathway positive regulation of immune response regulation of immune system process signal transduction positive regulation of immune system process regulation of biological process cell surface receptor signaling pathway immune response-activating cell surface receptor signaling pathway immune response B cell receptor signaling pathway biological regulation regulation of response to stimulus immune system process regulation of immune response cellular process antigen receptor-mediated signaling pathway activation of immune response adaptive immune response adaptive immune response based on somatic recombination of immune receptors built from immunoglobulin superfamily domains lymphocyte mediated immunity humoral immune response complement activation humoral immune response mediated by circulating immunoglobulin leukocyte mediated immunity complement activation, classical pathway immunoglobulin mediated immune response immune effector process B cell mediated immunity biological process involved in interspecies interaction between organisms response to other organism defense response antibacterial humoral response defense response to symbiont response to external stimulus antimicrobial humoral response response to biotic stimulus defense response to bacterium defense response to other organism response to stress response to bacterium response to external biotic stimulus multicellular organismal process renal system process system process glomerular filtration renal filtration positive regulation of respiratory burst positive regulation of metabolic process respiratory burst metabolic process regulation of respiratory burst regulation of metabolic process positive regulation of cellular process	protein-containing complex IgA immunoglobulin complex immunoglobulin complex IgA immunoglobulin complex, circulating cellular anatomical structure secretory IgA immunoglobulin complex extracellular region extracellular space polymeric IgA immunoglobulin complex immunoglobulin complex, circulating extracellular exosome membrane-bounded organelle extracellular vesicle extracellular organelle protein-containing complex IgA immunoglobulin complex immunoglobulin complex IgA immunoglobulin complex, circulating cellular anatomical structure secretory IgA immunoglobulin complex extracellular region extracellular space polymeric IgA immunoglobulin complex immunoglobulin complex, circulating extracellular exosome membrane-bounded organelle extracellular vesicle extracellular organelle organelle vesicle extracellular membrane-bounded organelle cell periphery plasma membrane membrane dimeric IgA immunoglobulin complex secretory dimeric IgA immunoglobulin complex IgG immunoglobulin complex blood microparticle monomeric IgA immunoglobulin complex
A [auth L], B [auth M]	Immunoglobulin A1 light chain	-	-	-

InterPro: Protein Family Classification InterPro Database Homepage

Chains	Accession	Name	Type
E [auth C]	IPR020857	Serum albumin, conserved site	Conserved Site
E [auth C]	IPR000264	ALB/AFP/VDB	Family
E [auth C]	IPR014760	Serum albumin, N-terminal	Domain
E [auth C]	IPR020858	Serum albumin-like	Homologous Superfamily
E [auth C]	IPR021177	Serum albumin/Alpha-fetoprotein/Afamin	Family
C [auth A], D [auth B]	IPR036179	Immunoglobulin-like domain superfamily	Homologous Superfamily
C [auth A], D [auth B]	IPR003597	Immunoglobulin C1-set	Domain
C [auth A], D [auth B]	IPR003006	Immunoglobulin/major histocompatibility complex, conserved site	Conserved Site
C [auth A], D [auth B]	IPR013151	Immunoglobulin-like beta-sandwich domain	Domain
C [auth A], D [auth B]	IPR050380	Immune Recognition and Response Modulators	Family
C [auth A], D [auth B]	IPR013783	Immunoglobulin-like fold	Homologous Superfamily
C [auth A], D [auth B]	IPR007110	Immunoglobulin-like domain	Domain

Pharos: Disease Associations Pharos Homepage Annotation

Chains	Drug Target	Associated Disease
E [auth C]	Pharos: P02768	thrombocytopenia pancreatitis Stevens-Johnson syndrome allergic disease hyperthyroxinemia, familial dysalbuminemic angioedema myopathy heart disease hemolytic-uremic syndrome uveitis membranous glomerulonephritis adult acute respiratory distress syndrome nephrotic syndrome glomerulonephritis kidney disease thrombocytopenia pancreatitis Stevens-Johnson syndrome allergic disease hyperthyroxinemia, familial dysalbuminemic angioedema myopathy heart disease hemolytic-uremic syndrome uveitis membranous glomerulonephritis adult acute respiratory distress syndrome nephrotic syndrome glomerulonephritis kidney disease HIV infectious disease echinococcosis hypertensive disorder interstitial nephritis Pain diabetic peripheral angiopathy melancholia urticaria congenital analbuminemia nephrosis serum sickness keloid hepatitis brain disease membranoproliferative glomerulonephritis cardiovascular disease cerebrovascular disorder endogenous depression anuria nephritis congestive heart failure aseptic meningitis azoospermia brain ischemia acute liver failure epilepsy poisoning chronic kidney disease cirrhosis of liver proteinuria influenza coronary artery disease neurodegenerative disease asthma respiratory failure dense deposit disease non-alcoholic fatty liver disease autoimmune disease bone marrow disease hepatitis C virus infection toxic epidermal necrolysis lymphatic system disease breast disease type IV hypersensitivity disease pancreatic intraductal papillary-mucinous neoplasm cancer perennial allergic rhinitis Ehlers-Danlos syndrome, arthrochalasis type peritonitis primary biliary cholangitis chronic obstructive pulmonary disease arthritic joint disease protein-energy malnutrition inborn carbohydrate metabolic disorder gastric neoplasm psoriasis inherited lipid metabolism disorder COVID-19 neurotic disorder atherosclerosis respiratory system disease obesity disorder diabetic kidney disease brain injury liver disease diabetic retinopathy breast cancer tuberculosis pancreatic ductal adenocarcinoma hereditary diffuse gastric adenocarcinoma pancreatic intraductal papillary-mucinous neoplasm with low grade dysplasia peripheral neuropathy hyperglycemia muscle tissue disease pneumonia cholestasis esophageal varices primary membranoproliferative glomerulonephritis hypotensive disorder protein-losing enteropathy inflammatory bowel disease dementia heart failure skin disease depressive disorder hepatic encephalopathy stomach disease leukopenia hepatitis B virus infection thrombotic disease lung adenocarcinoma diarrheal disease pancreas disease breast carcinoma type 2 diabetes mellitus malignant pancreatic neoplasm acute kidney failure pancreatic intraductal papillary-mucinous carcinoma hereditary hyperbilirubinemia C1 inhibitor deficiency urinary tract infection drug-induced liver injury varicose disease metabolic acidosis peripheral vascular disease hyperparathyroidism muscular disease anemia hypoglycemia extrahepatic cholestasis prostate carcinoma idiopathic membranous glomerulonephritis nephrosclerosis gastric cancer
C [auth A], D [auth B]	Pharos: P01876	breast cancer psoriasis

RCSB PDB Core Operations are funded by the U.S. National Science Foundation (DBI-2321666), the US Department of Energy (DE-SC0019749), and the National Cancer Institute, National Institute of Allergy and Infectious Diseases, and National Institute of General Medical Sciences of the National Institutes of Health under grant R01GM157729. RCSB PDB uses resources of the National Energy Research Scientific Computing Center (NERSC), a Department of Energy User Facility.