Annotations: 5F4E

Domain Annotation: SCOP2 Classification SCOP2 Database Homepage

Chains	Type	Family Name	Domain Identifier	Family Identifier	Provenance Source (Version)
A	SCOP2B Superfamily	IZUMO1 N-terminal domain-like	8092638	3002613	SCOP2B (2022-06-29)
A	SCOP2B Superfamily	Immunoglobulin (Ig) domain-like	8092637	3000071	SCOP2B (2022-06-29)
B	SCOP2B Superfamily	Frizzled domain-like	8090926	3001950	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)
A	I-set_2	e5f4eA2	A: beta sandwiches	X: Immunoglobulin-like beta-sandwich	H: Immunoglobulin-related	T: Immunoglobulin/Fibronectin type III/E set domains/PapD-like	F: I-set_2	ECOD (1.6)
A	IZUMO	e5f4eA1	A: alpha bundles	X: N-cbl like	H: Izumo sperm-egg fusion protein 1 N-terminal domain (From Topology)	T: Izumo sperm-egg fusion protein 1 N-terminal domain	F: IZUMO	ECOD (1.6)
B	Folate_rec	e5f4eB1	A: few secondary structure elements	X: Frizzled cysteine-rich domain-related (From Topology)	H: Frizzled cysteine-rich domain-related (From Topology)	T: Frizzled cysteine-rich domain-related	F: Folate_rec	ECOD (1.6)

Protein Family Annotation Pfam Database Homepage

Chains	Accession	Name	Description	Comments	Source
A	PF16706	Izumo-like Immunoglobulin domain (Izumo-Ig)	Izumo-like Immunoglobulin domain	Izumo-Ig is the immunoglobulin domain on Izumo proteins from higher eukaryotes. Izumo is a typical type I membrane glycoprotein with one immunoglobulin-like domain and a putative N-glycoside link motif - glycosylation site. The full-length protein, e ...	Izumo-Ig is the immunoglobulin domain on Izumo proteins from higher eukaryotes. Izumo is a typical type I membrane glycoprotein with one immunoglobulin-like domain and a putative N-glycoside link motif - glycosylation site. The full-length protein, eg Swiss:Q8IYV9, is a molecule with a single immunoglobulin (Ig) domain. It is thought that Izumo proteins bind to putative Izumo receptors on the oocyte. Izumo is not detectable on the surface of fresh sperm but becomes exposed only after an exocytotic process, the acrosome reaction, has occurred. Studies have shown that knock-out mice (Izumo-/- males) were sterile despite normal mating behaviour and ejaculation, indicating the importance of the protein in fertilisation [1]. There is a conserved GCL sequence motif. Izumo expression has been found to be testis-specific [1,2].	Domain
A	PF15005	Izumo sperm-egg fusion, Ig domain-associated (IZUMO)	Izumo sperm-egg fusion, Ig domain-associated	-	Family
B	PF03024	Folate receptor family (Folate_rec)	Folate receptor family	This family includes the folate receptor which binds to folate and reduced folic acid derivatives and mediates delivery of 5-methyltetrahydrofolate to the interior of cells. These proteins are attached to the membrane by a GPI-anchor. The proteins co ...	This family includes the folate receptor which binds to folate and reduced folic acid derivatives and mediates delivery of 5-methyltetrahydrofolate to the interior of cells. These proteins are attached to the membrane by a GPI-anchor. The proteins contain 16 conserved cysteines that form eight disulphide bridges.	Domain

Gene Ontology: Gene Product Annotation Gene Ontology Database Homepage

Chains	Polymer	Molecular Function	Biological Process	Cellular Component
A	Izumo sperm-egg fusion protein 1	protein binding binding signaling receptor binding identical protein binding protein homodimerization activity protein dimerization activity cell adhesion molecule binding cell adhesion mediator activity cell-cell adhesion mediator activity protein binding involved in heterotypic cell-cell adhesion	membrane organization sexual reproduction membrane fusion reproductive process plasma membrane fusion fertilization multicellular organismal reproductive process cellular process involved in reproduction in multicellular organism cellular component organization fusion of sperm to egg plasma membrane involved in single fertilization plasma membrane organization cellular process cellular component organization or biogenesis endomembrane system organization membrane organization sexual reproduction membrane fusion reproductive process plasma membrane fusion fertilization multicellular organismal reproductive process cellular process involved in reproduction in multicellular organism cellular component organization fusion of sperm to egg plasma membrane involved in single fertilization plasma membrane organization cellular process cellular component organization or biogenesis endomembrane system organization single fertilization sperm-egg recognition cell-cell recognition cell recognition cell adhesion heterotypic cell-cell adhesion cell-cell adhesion	membrane cellular anatomical entity protein complex involved in cell-cell adhesion protein-containing complex protein complex involved in cell adhesion cell periphery plasma membrane membrane-bounded organelle acrosomal vesicle intracellular anatomical structure intracellular vesicle acrosomal membrane intracellular membrane-bounded organelle endomembrane system membrane cellular anatomical entity protein complex involved in cell-cell adhesion protein-containing complex protein complex involved in cell adhesion cell periphery plasma membrane membrane-bounded organelle acrosomal vesicle intracellular anatomical structure intracellular vesicle acrosomal membrane intracellular membrane-bounded organelle endomembrane system intracellular organelle cytoplasmic vesicle membrane bounding membrane of organelle vesicle membrane cytoplasmic vesicle organelle secretory granule secretory vesicle cytoplasm vesicle organelle membrane secretory granule membrane organelle subcompartment endoplasmic reticulum subcompartment nuclear outer membrane-endoplasmic reticulum membrane network endoplasmic reticulum endoplasmic reticulum membrane
B	Sperm-egg fusion protein Juno	molecular transducer activity signaling receptor activity protein binding binding signaling receptor binding	membrane organization sexual reproduction membrane fusion reproductive process plasma membrane fusion fertilization multicellular organismal reproductive process cellular process involved in reproduction in multicellular organism cellular component organization fusion of sperm to egg plasma membrane involved in single fertilization plasma membrane organization cellular process cellular component organization or biogenesis endomembrane system organization membrane organization sexual reproduction membrane fusion reproductive process plasma membrane fusion fertilization multicellular organismal reproductive process cellular process involved in reproduction in multicellular organism cellular component organization fusion of sperm to egg plasma membrane involved in single fertilization plasma membrane organization cellular process cellular component organization or biogenesis endomembrane system organization single fertilization sperm-egg recognition cell-cell recognition cell recognition cell adhesion	membrane plasma membrane cellular anatomical entity plasma membrane bounded cell projection cell periphery cell projection actin-based cell projection plasma membrane region microvillus microvillus membrane cell projection membrane cell surface external side of plasma membrane side of membrane membrane plasma membrane cellular anatomical entity plasma membrane bounded cell projection cell periphery cell projection actin-based cell projection plasma membrane region microvillus microvillus membrane cell projection membrane cell surface external side of plasma membrane side of membrane extracellular region

InterPro: Protein Family Classification InterPro Database Homepage

Chains	Accession	Name	Type
A	IPR029389	Izumo sperm-egg fusion protein	Family
A	IPR036179	Immunoglobulin-like domain superfamily	Homologous Superfamily
A	IPR032699	Izumo protein, immunoglobulin domain	Domain
A	IPR032700	Izumo sperm-egg fusion protein 1	Family
A	IPR013783	Immunoglobulin-like fold	Homologous Superfamily
B	IPR004269	Folate receptor	Family
B	IPR018143	Folate receptor-like	Domain

Pharos: Disease Associations Pharos Homepage Annotation

Chains	Drug Target	Associated Disease
A	Pharos: Q8IYV9	psoriasis attention deficit hyperactivity disorder, inattentive type colorectal cancer gallbladder disease Behcet disease Crohn disease inflammatory bowel disease cholelithiasis dental caries non-alcoholic fatty liver disease
B	Pharos: A6ND01	obstructive sleep apnea syndrome

RCSB PDB Core Operations are funded by the National Science Foundation (DBI-1832184), 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 R01GM133198.