9MYL | pdb_00009myl

Fertilization IZUMO1 Protein Ectodomain in Complex with Anti-sperm Antibody OBF13

External Resource: Annotation

Domain Annotation: SCOP2 Classification
SAbDab Antibody Annotation
Protein Family Annotation
Gene Ontology: Gene Product Annotation
InterPro: Protein Family Classification

Domain Annotation: SCOP2 Classification SCOP2 Database Homepage

Chains	Type	Family Name	Domain Identifier	Family Identifier	Provenance Source (Version)
B [auth D]	SCOP2B Superfamily	IZUMO1 N-terminal domain-like	8092640	3002613	SCOP2B (2022-06-29)
A [auth C]	SCOP2B Superfamily	Immunoglobulin (Ig) domain-like	8092639	3000071	SCOP2B (2022-06-29)
A [auth C]	SCOP2B Superfamily	IZUMO1 N-terminal domain-like	8092640	3002613	SCOP2B (2022-06-29)

SAbDab Antibody Annotation SAbDab Database Homepage

Chain	Chain Class	Chain Subclass	Chain Type	Antigen Name(s)	Provenance Source
D [auth L], F [auth B]	Light Chain	IGKV6	Kappa	izumo sperm-egg fusion protein 1	SAbDab (2025-12-19)
C [auth H], E [auth A]	Heavy Chain	IGHV14	-	izumo sperm-egg fusion protein 1	SAbDab (2025-12-19)

Protein Family Annotation Pfam Database Homepage

Chains	Accession	Name	Description	Comments	Source
A [auth C], B [auth D]	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 [auth C], B [auth D]	PF15005	Izumo sperm-egg fusion, Ig domain-associated (IZUMO)	Izumo sperm-egg fusion, Ig domain-associated	-	Family

Gene Ontology: Gene Product Annotation Gene Ontology Database Homepage

Chains	Polymer	Molecular Function	Biological Process	Cellular Component
D [auth L], F [auth B]	Anti-sperm antibody OBF13 light chain	-	-	-
C [auth H], E [auth A]	Anti-sperm antibody OBF13 heavy chain	-	-	-
A [auth C], B [auth D]	Izumo sperm-egg fusion protein 1	protein binding binding signaling receptor binding identical protein binding protein homodimerization activity protein dimerization activity molecular function activator activity molecular function regulator activity signaling receptor regulator activity receptor ligand activity signaling receptor activator activity cell adhesion molecule binding cell adhesion mediator activity cell-cell adhesion mediator activity protein binding binding signaling receptor binding identical protein binding protein homodimerization activity protein dimerization activity molecular function activator activity molecular function regulator activity signaling receptor regulator activity receptor ligand activity signaling receptor activator 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 developmental process syncytium formation by plasma membrane fusion anatomical structure morphogenesis anatomical structure formation involved in morphogenesis anatomical structure development cell-cell fusion syncytium formation cell adhesion	cellular anatomical structure membrane 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 cellular anatomical structure membrane 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

InterPro: Protein Family Classification InterPro Database Homepage

Chains	Accession	Name	Type
A [auth C], B [auth D]	IPR029389	Izumo sperm-egg fusion protein	Family
A [auth C], B [auth D]	IPR036179	Immunoglobulin-like domain superfamily	Homologous Superfamily
A [auth C], B [auth D]	IPR032699	Izumo protein, immunoglobulin domain	Domain
A [auth C], B [auth D]	IPR032700	Izumo sperm-egg fusion protein 1	Family

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.