Annotations: 8ECZ

Domain Annotation: ECOD Classification ECOD Database Homepage

Chains	Family Name	Domain Identifier	Architecture	Possible Homology	Homology	Topology	Family	Provenance Source (Version)
C [auth A]	Polyketide_cyc2	e8eczA2	A: a/b three-layered sandwiches	X: RNase A-like	H: RNase A-like	T: RNase A-like	F: Polyketide_cyc2	ECOD (v294.1)
A [auth L]	Bcl-2	e8eczL1	A: a/b three-layered sandwiches	X: RNase A-like	H: RNase A-like	T: RNase A-like	F: Bcl-2	ECOD (v294.1)
D [auth B]	Polyketide_cyc2	e8eczB1	A: a/b three-layered sandwiches	X: RNase A-like	H: RNase A-like	T: RNase A-like	F: Polyketide_cyc2	ECOD (v294.1)
B [auth H]	Bcl-2	e8eczH1	A: a/b three-layered sandwiches	X: RNase A-like	H: RNase A-like	T: RNase A-like	F: Bcl-2	ECOD (v294.1)

SAbDab Antibody Annotation SAbDab Database Homepage

Chain	Chain Class	Chain Subclass	Chain Type	Antigen Name(s)	Provenance Source
A [auth L], C [auth A]	Light Chain	IGLV1	Lambda	-	SAbDab (2026-03-27)
B [auth H], D [auth B]	Heavy Chain	IGHV1	-	-	SAbDab (2026-03-27)

Protein Family Annotation Pfam Database Homepage

Chains	Accession	Name	Description	Comments	Source
A [auth L], C [auth A]	PF07654	Immunoglobulin C1-set domain (C1-set)	Immunoglobulin C1-set domain		Domain

Gene Ontology: Gene Product Annotation Gene Ontology Database Homepage

Chains	Polymer	Molecular Function	Biological Process	Cellular Component
A [auth L], C [auth A]	4C1 Fab light chain	binding antigen binding	adaptive immune response based on somatic recombination of immune receptors built from immunoglobulin superfamily domains lymphocyte mediated immunity response to stimulus immune response immune system process B cell mediated immunity leukocyte mediated immunity immunoglobulin mediated immune response adaptive immune response immune effector process	cellular anatomical structure extracellular region extracellular space blood microparticle extracellular exosome membrane-bounded organelle extracellular vesicle extracellular organelle organelle vesicle extracellular membrane-bounded organelle cell periphery plasma membrane membrane cellular anatomical structure extracellular region extracellular space blood microparticle extracellular exosome membrane-bounded organelle extracellular vesicle extracellular organelle organelle vesicle extracellular membrane-bounded organelle cell periphery plasma membrane membrane IgG immunoglobulin complex protein-containing complex immunoglobulin complex
B [auth H], D [auth B]	4C1 Fab heavy chain	-	response to stimulus immune response immune system process adaptive immune response	cell periphery cellular anatomical structure plasma membrane membrane protein-containing complex immunoglobulin complex extracellular region

InterPro: Protein Family Classification InterPro Database Homepage

Chains	Accession	Name	Type
A [auth L], C [auth A]	IPR036179	Immunoglobulin-like domain superfamily	Homologous Superfamily
A [auth L], C [auth A]	IPR050160	Major Histocompatibility Complex/Immunoglobulin	Family
A [auth L], C [auth A]	IPR003597	Immunoglobulin C1-set	Domain
A [auth L], C [auth A]	IPR013783	Immunoglobulin-like fold	Homologous Superfamily
A [auth L], C [auth A]	IPR007110	Immunoglobulin-like domain	Domain
A [auth L], C [auth A]	IPR003006	Immunoglobulin/major histocompatibility complex, conserved site	Conserved Site
B [auth H], D [auth B]	IPR003597	Immunoglobulin C1-set	Domain
B [auth H], D [auth B]	IPR013783	Immunoglobulin-like fold	Homologous Superfamily
B [auth H], D [auth B]	IPR036179	Immunoglobulin-like domain superfamily	Homologous Superfamily
B [auth H], D [auth B]	IPR013106	Immunoglobulin V-set domain	Domain
B [auth H], D [auth B]	IPR003599	Immunoglobulin domain subtype	Domain
B [auth H], D [auth B]	IPR007110	Immunoglobulin-like domain	Domain
B [auth H], D [auth B]	IPR050380	Immune Recognition and Response Modulators	Family
B [auth H], D [auth B]	IPR003006	Immunoglobulin/major histocompatibility complex, conserved site	Conserved Site

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.