Annotations: 8ECZ

Chain	Chain Class	Chain Subclass	Chain Type	Antigen Name(s)	Provenance Source
B [auth H], D [auth B]	Heavy Chain	IGHV1	-	-	SAbDab (2026-02-06)
A [auth L], C [auth A]	Light Chain	IGLV1	Lambda	-	SAbDab (2026-02-06)

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

Chains	Polymer	Molecular Function	Biological Process	Cellular Component
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
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

Chains	Accession	Name	Type
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
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