Annotations: 3BSZ

Crystal structure of the transthyretin-retinol binding protein-Fab complex

External Resource: Annotation

Domain Annotation: ECOD Classification
Domain Annotation: CATH
IMGT Antibody Annotation
SAbDab Antibody Annotation
Protein Family Annotation
Gene Ontology: Gene Product Annotation
InterPro: Protein Family Classification
Pharos: Disease Associations

Domain Annotation: ECOD Classification ECOD Database Homepage

Chains	Family Name	Domain Identifier	Architecture	Possible Homology	Homology	Topology	Family	Provenance Source (Version)
J [auth N]	zf-CCCH_4	e3bszN1	A: alpha arrays	X: HTH	H: HTH	T: tetra-helical, lambda repressor-like	F: zf-CCCH_4	ECOD (v295.2)
H	CRISPR_Cas2	e3bszH1	A: alpha arrays	X: OB-fold	H: Nucleic acid-binding protein	T: Nucleic acid-binding protein	F: CRISPR_Cas2	ECOD (v295.2)
I [auth M]	zf-CCCH_4	e3bszM1	A: alpha arrays	X: HTH	H: HTH	T: tetra-helical, lambda repressor-like	F: zf-CCCH_4	ECOD (v295.2)
G [auth L]	zf-CCCH_4	e3bszL1	A: alpha arrays	X: HTH	H: HTH	T: tetra-helical, lambda repressor-like	F: zf-CCCH_4	ECOD (v295.2)
F	zf-CCCH_4	e3bszF1	A: alpha arrays	X: HTH	H: HTH	T: tetra-helical, lambda repressor-like	F: zf-CCCH_4	ECOD (v295.2)
E	zf-CCCH_4	e3bszE1	A: alpha arrays	X: HTH	H: HTH	T: tetra-helical, lambda repressor-like	F: zf-CCCH_4	ECOD (v295.2)
A	zf-CCCH_4	e3bszA1	A: alpha arrays	X: HTH	H: HTH	T: tetra-helical, lambda repressor-like	F: zf-CCCH_4	ECOD (v295.2)
B	zf-CCCH_4	e3bszB1	A: alpha arrays	X: HTH	H: HTH	T: tetra-helical, lambda repressor-like	F: zf-CCCH_4	ECOD (v295.2)
D	zf-CCCH_4	e3bszD1	A: alpha arrays	X: HTH	H: HTH	T: tetra-helical, lambda repressor-like	F: zf-CCCH_4	ECOD (v295.2)
C	zf-CCCH_4	e3bszC1	A: alpha arrays	X: HTH	H: HTH	T: tetra-helical, lambda repressor-like	F: zf-CCCH_4	ECOD (v295.2)

Domain Annotation: CATH CATH Database Homepage

Chain	Domain	Class	Architecture	Topology	Homology	Provenance Source (Version)
J [auth N]	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
H	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
I [auth M]	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
G [auth L]	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
F	2.40.128.20	Mainly Beta	Beta Barrel	Lipocalin	Calycin beta-barrel core domain	CATH (4.3.0)
E	2.40.128.20	Mainly Beta	Beta Barrel	Lipocalin	Calycin beta-barrel core domain	CATH (4.3.0)
A	2.60.40.180	Mainly Beta	Sandwich	Immunoglobulin-like	Transthyretin/hydroxyisourate hydrolase domain	CATH (4.3.0)
B	2.60.40.180	Mainly Beta	Sandwich	Immunoglobulin-like	Transthyretin/hydroxyisourate hydrolase domain	CATH (4.3.0)
D	2.60.40.180	Mainly Beta	Sandwich	Immunoglobulin-like	Transthyretin/hydroxyisourate hydrolase domain	CATH (4.3.0)
C	2.60.40.180	Mainly Beta	Sandwich	Immunoglobulin-like	Transthyretin/hydroxyisourate hydrolase domain	CATH (4.3.0)

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
H, J [auth N]	Anti-RBP Fab	VH-CH1	Mus musculus (house mouse)	IGHV1-501, IGHJ101, IGHJ102, IGHJ103, IGHG1*01	V-DOMAIN VH, C-DOMAIN CH1	IG	FAB-GAMMA-1_KAPPA	IMGT (202640-0)
G [auth L], I [auth M]	Anti-RBP Fab	L-KAPPA	Mus musculus (house mouse)	IGKV3-501, IGKJ102, IGKJ201, IGKC01, IGKC*02	V-DOMAIN V-KAPPA, C-DOMAIN C-KAPPA	IG	FAB-GAMMA-1_KAPPA	IMGT (202640-0)

SAbDab Antibody Annotation SAbDab Database Homepage

Chain	Chain Class	Chain Subclass	Chain Type	Antigen Name(s)	Provenance Source
H, J [auth N]	Heavy Chain	IGHV1	-	plasma retinol-binding protein	SAbDab (2026-10-16)
G [auth L], I [auth M]	Light Chain	IGKV3	Kappa	plasma retinol-binding protein	SAbDab (2026-10-16)

Protein Family Annotation Pfam Database Homepage

Chains	Accession	Name	Description	Comments	Source
G [auth L], I [auth M]	PF07686	Immunoglobulin V-set domain (V-set)	Immunoglobulin V-set domain	This domain is found in antibodies as well as neural protein P0 and CTL4 amongst others.	Domain
G [auth L], I [auth M]	PF07654	Immunoglobulin C1-set domain (C1-set)	Immunoglobulin C1-set domain		Domain
E, F	PF00061	Lipocalin / cytosolic fatty-acid binding protein family (Lipocalin)	Lipocalin / cytosolic fatty-acid binding protein family	Lipocalins are transporters for small hydrophobic molecules, such as lipids, steroid hormones, bilins, and retinoids. The family also encompasses the enzyme prostaglandin D synthase (EC:5.3.99.2). Alignment subsumes both the lipocalin and fatty acid ...	Lipocalins are transporters for small hydrophobic molecules, such as lipids, steroid hormones, bilins, and retinoids. The family also encompasses the enzyme prostaglandin D synthase (EC:5.3.99.2). Alignment subsumes both the lipocalin and fatty acid binding protein signatures from PROSITE. This is supported on structural and functional grounds. The structure is an eight-stranded beta barrel.	Domain
A, B, C, D	PF00576	HIUase/Transthyretin family (Transthyretin)	HIUase/Transthyretin family	This family includes transthyretin that is a thyroid hormone-binding protein that transports thyroxine from the bloodstream to the brain. However, most of the sequences listed in this family do not bind thyroid hormones. They are actually enzymes of ...	This family includes transthyretin that is a thyroid hormone-binding protein that transports thyroxine from the bloodstream to the brain. However, most of the sequences listed in this family do not bind thyroid hormones. They are actually enzymes of the purine catabolism that catalyse the conversion of 5-hydroxyisourate (HIU) to OHCU [2,3]. HIU hydrolysis is the original function of the family and is conserved from bacteria to mammals; transthyretins arose by gene duplications in the vertebrate lineage [4]. HIUases are distinguished in the alignment from the conserved C-terminal YRGS sequence.	Domain

Gene Ontology: Gene Product Annotation Gene Ontology Database Homepage

Chains	Polymer	Molecular Function	Biological Process	Cellular Component
H, J [auth N]	Fab fragment light chain	-	-	-
G [auth L], I [auth M]	Fab fragment heavy chain	-	-	-
E, F	Plasma retinol-binding protein	vitamin binding binding alcohol binding isoprenoid binding retinoid binding lipid binding retinol binding small molecule binding molecular carrier activity protein-containing complex binding alcohol transmembrane transporter activity retinol transmembrane transporter activity lipid transmembrane transporter activity vitamin transmembrane transporter activity vitamin binding binding alcohol binding isoprenoid binding retinoid binding lipid binding retinol binding small molecule binding molecular carrier activity protein-containing complex binding alcohol transmembrane transporter activity retinol transmembrane transporter activity lipid transmembrane transporter activity vitamin transmembrane transporter activity transporter activity transmembrane transporter activity all-trans-retinol binding	response to stimulus response to activity response to muscle activity response to chemical response to xenobiotic stimulus multicellular organismal process maintenance of gastrointestinal epithelium system process digestion multicellular organismal-level homeostasis epithelial structure maintenance homeostatic process digestive system process anatomical structure homeostasis response to stimulus response to activity response to muscle activity response to chemical response to xenobiotic stimulus multicellular organismal process maintenance of gastrointestinal epithelium system process digestion multicellular organismal-level homeostasis epithelial structure maintenance homeostatic process digestive system process anatomical structure homeostasis tissue homeostasis developmental process heart development multicellular organism development anatomical structure development animal organ development animal gross anatomical part developmental process circulatory system development system development camera-type eye morphogenesis sensory organ development eye development embryonic morphogenesis visual system development retina development in camera-type eye embryo development retina morphogenesis in camera-type eye anatomical structure morphogenesis eye morphogenesis embryonic retina morphogenesis in camera-type eye sensory organ morphogenesis camera-type eye development animal organ morphogenesis sensory system development urinary bladder development renal system development genitalia development reproductive system development reproductive process female genitalia development sex differentiation female sex differentiation developmental process involved in reproduction vagina development reproductive structure development embryonic organ morphogenesis embryonic organ development tube development respiratory tube development lung development respiratory system development genitalia morphogenesis female genitalia morphogenesis regulation of growth regulation of cellular process regulation of cardiac muscle tissue growth developmental growth negative regulation of biological process negative regulation of growth regulation of organ growth regulation of heart growth regulation of cardiac muscle cell proliferation muscle cell proliferation cardiac muscle tissue growth muscle tissue development striated muscle cell proliferation regulation of biological process heart growth cell population proliferation tissue development negative regulation of developmental growth regulation of cell population proliferation negative regulation of multicellular organismal process negative regulation of cardiac muscle cell proliferation regulation of developmental process cardiac muscle cell proliferation negative regulation of cardiac muscle tissue growth organ growth striated muscle tissue development negative regulation of organ growth negative regulation of cellular process regulation of multicellular organismal process negative regulation of cell population proliferation regulation of multicellular organismal development regulation of developmental growth negative regulation of heart growth cardiac muscle tissue development negative regulation of developmental process biological regulation growth cellular process response to retinoic acid response to lipid response to oxygen-containing compound cardiac chamber morphogenesis heart trabecula formation heart morphogenesis anatomical structure formation involved in morphogenesis cardiac chamber development heart trabecula morphogenesis trabecula formation trabecula morphogenesis response to alcohol response to ethanol uterus development regulation of immune effector process immunoglobulin production positive regulation of biological process positive regulation of macromolecule biosynthetic process positive regulation of metabolic process positive regulation of biosynthetic process positive regulation of immune effector process regulation of immune system process positive regulation of macromolecule metabolic process positive regulation of immune system process positive regulation of cellular process positive regulation of immunoglobulin production regulation of biosynthetic process production of molecular mediator of immune response regulation of macromolecule metabolic process gene expression macromolecule biosynthetic process immune effector process regulation of gene expression biosynthetic process regulation of immunoglobulin production positive regulation of gene expression immune system process positive regulation of production of molecular mediator of immune response regulation of macromolecule biosynthetic process metabolic process regulation of production of molecular mediator of immune response macromolecule metabolic process regulation of metabolic process chordate embryonic development embryo development ending in birth or egg hatching skeletal system development embryonic skeletal system development monosaccharide metabolic process carbohydrate metabolic process small molecule biosynthetic process carbohydrate biosynthetic process hexose metabolic process primary metabolic process monosaccharide biosynthetic process gluconeogenesis hexose biosynthetic process small molecule metabolic process glucose metabolic process localization transport macromolecule localization lipid localization lipid transport organic hydroxy compound transport establishment of localization terpenoid transport isoprenoid transport retinol transport positive regulation of cell communication regulation of localization establishment of protein localization nitrogen compound transport positive regulation of establishment of protein localization cell communication positive regulation of insulin secretion intracellular protein localization regulation of biological quality regulation of peptide hormone secretion regulation of hormone levels positive regulation of peptide hormone secretion establishment of protein localization to extracellular region protein secretion regulation of protein secretion regulation of secretion positive regulation of protein localization regulation of hormone secretion regulation of protein localization regulation of peptide secretion signaling positive regulation of secretion by cell hormone secretion protein localization to extracellular region positive regulation of protein transport peptide secretion regulation of secretion by cell secretion by cell positive regulation of hormone secretion positive regulation of secretion signal release positive regulation of peptide secretion regulation of signaling regulation of transport secretion regulation of peptide transport regulation of establishment of protein localization export from cell cell-cell signaling regulation of protein transport positive regulation of protein secretion peptide transport positive regulation of transport protein transport regulation of insulin secretion peptide hormone secretion hormone transport regulation of cell communication insulin secretion positive regulation of signaling chemical homeostasis glucose homeostasis carbohydrate homeostasis diterpenoid metabolic process retinoid metabolic process terpenoid metabolic process isoprenoid metabolic process lipid metabolic process alcohol metabolic process hormone metabolic process olefinic compound metabolic process retinol metabolic process primary alcohol metabolic process	extracellular exosome membrane-bounded organelle extracellular vesicle cellular anatomical structure extracellular organelle extracellular region organelle vesicle extracellular membrane-bounded organelle protein-containing complex
A, B, C, D	Transthyretin	protein-containing complex binding binding molecular sequestering activity hormone binding identical protein binding protein binding	nucleobase-containing compound metabolic process purine nucleobase metabolic process nucleobase-containing small molecule metabolic process nucleobase metabolic process small molecule metabolic process metabolic process cellular process primary metabolic process purine-containing compound metabolic process diterpenoid metabolic process retinoid metabolic process terpenoid metabolic process isoprenoid metabolic process lipid metabolic process	cellular anatomical structure extracellular region extracellular exosome membrane-bounded organelle extracellular vesicle extracellular organelle organelle vesicle extracellular membrane-bounded organelle intracellular anatomical structure lytic vacuole intracellular vesicle membrane-enclosed lumen cytoplasmic vesicle lumen cellular anatomical structure extracellular region extracellular exosome membrane-bounded organelle extracellular vesicle extracellular organelle organelle vesicle extracellular membrane-bounded organelle intracellular anatomical structure lytic vacuole intracellular vesicle membrane-enclosed lumen cytoplasmic vesicle lumen vacuolar lumen endomembrane system intracellular organelle lumen intracellular organelle cytoplasmic vesicle lysosome vesicle lumen azurophil granule vacuole intracellular membrane-bounded organelle secretory granule lumen azurophil granule lumen organelle lumen secretory granule primary lysosome secretory vesicle cytoplasm protein-containing complex

InterPro: Protein Family Classification InterPro Database Homepage

Chains	Accession	Name	Type
E, F	IPR000566	Lipocalin/cytosolic fatty-acid binding domain	Domain
E, F	IPR022272	Lipocalin family conserved site	Conserved Site
E, F	IPR022271	Lipocalin, ApoD type	Family
E, F	IPR002449	Retinol binding protein/Purpurin	Family
E, F	IPR012674	Calycin superfamily	Homologous Superfamily
A, B, C, D	IPR036817	Transthyretin/hydroxyisourate hydrolase domain superfamily	Homologous Superfamily
A, B, C, D	IPR023418	Transthyretin, thyroxine binding site	Binding Site
A, B, C, D	IPR023419	Transthyretin, conserved site	Conserved Site
A, B, C, D	IPR023416	Transthyretin/hydroxyisourate hydrolase domain	Domain
A, B, C, D	IPR000895	Transthyretin/hydroxyisourate hydrolase	Family

Pharos: Disease Associations Pharos Homepage Annotation

Chains	Drug Target	Associated Disease
E, F	: P02753	microphthalmia, isolated, with coloboma 10 progressive retinal dystrophy due to retinol transport defect keratomalacia vitamin A deficiency polycystic ovary syndrome Necrosis sarcomatoid carcinoma microphthalmia congestive heart failure kidney disease alcoholic liver diseases carcinoma gastric cancer oligodendroglioma hereditary diffuse gastric adenocarcinoma microphthalmia, isolated, with coloboma 10 progressive retinal dystrophy due to retinol transport defect keratomalacia vitamin A deficiency polycystic ovary syndrome Necrosis sarcomatoid carcinoma microphthalmia congestive heart failure kidney disease alcoholic liver diseases carcinoma gastric cancer oligodendroglioma hereditary diffuse gastric adenocarcinoma pilocytic astrocytoma invasive ductal breast carcinoma psoriasis adrenal cortex adenoma lung carcinoma malignant mesothelioma atopic eczema mammary neoplasms, animal undifferentiated carcinoma breast carcinoma ductal breast carcinoma in situ gastric neoplasm non-small cell lung carcinoma heart failure ovarian cancer inborn carbohydrate metabolic disorder pituitary cancer primitive neuroectodermal tumor lung adenocarcinoma adrenal cortex carcinoma malignant ependymoma type 2 diabetes mellitus atypical teratoid rhabdoid tumor breast fibroadenoma coloboma cystic fibrosis Emery-Dreifuss muscular dystrophy myopathy glioblastoma obesity disorder Pick disease interstitial cystitis adenoma lung cancer sarcoidosis malignant glioma Sjogren syndrome astrocytic tumor ulcerative colitis breast cancer medulloblastoma microphthalmia with coloboma 1
A, B, C, D	: P02766	amyloidosis familial amyloid neuropathy carpal tunnel syndrome hyperthyroxinemia, dystransthyretinemic lattice corneal dystrophy peripheral neuropathy Transthyretin related familial amyloid cardiomyopathy carpal tunnel syndrome 1 diabetes mellitus pancreatic intraductal papillary-mucinous carcinoma peripheral nervous system disease drug-induced liver injury Riley-Day syndrome acquired metabolic disease hydrocephalus amyloidosis familial amyloid neuropathy carpal tunnel syndrome hyperthyroxinemia, dystransthyretinemic lattice corneal dystrophy peripheral neuropathy Transthyretin related familial amyloid cardiomyopathy carpal tunnel syndrome 1 diabetes mellitus pancreatic intraductal papillary-mucinous carcinoma peripheral nervous system disease drug-induced liver injury Riley-Day syndrome acquired metabolic disease hydrocephalus intellectual disability Charcot-Marie-Tooth disease medulloblastoma dilated cardiomyopathy osteosarcoma pancreatic intraductal papillary-mucinous neoplasm with low grade dysplasia psoriasis schizophrenia acute kidney failure kidney disease lung benign neoplasm lymphatic system disease depressive disorder periodic fever syndrome polyneuropathy rheumatoid arthritis Sjogren syndrome heart disease hereditary amyloidosis hypertrophic cardiomyopathy lung carcinoma