Annotations: 8U4V

Cryo-EM structure of human claudin-4 complex with Clostridium perfringens enterotoxin C-terminal domain, sFab COP-1, and Nanobody

External Resource: Annotation

Domain Annotation: SCOP2 Classification
Domain Annotation: ECOD Classification
SAbDab Antibody Annotation
Gene Ontology: Gene Product Annotation
InterPro: Protein Family Classification
Pharos: Disease Associations
Membrane Protein Annotation: PDBTM
Membrane Protein Annotation: mpstruc

Domain Annotation: SCOP2 Classification SCOP2 Database Homepage

Chains	Type	Family Name	Domain Identifier	Family Identifier	Provenance Source (Version)
A	SCOP2B Superfamily	Claudin-like	8092547	3002606	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)
E [auth K]		e8u4vK1	A: beta barrels	X: RNase A-like	H: RNase A-like	T: RNase A-like	F:	ECOD (v294.2)
D [auth H]		e8u4vH1	A: beta barrels	X: RNase A-like	H: RNase A-like	T: RNase A-like	F:	ECOD (v294.2)
C [auth L]		e8u4vL1	A: beta barrels	X: RNase A-like	H: RNase A-like	T: RNase A-like	F:	ECOD (v294.2)
B		e8u4vB1	A: beta barrels	X: RNase A-like	H: RNase A-like	T: RNase A-like	F:	ECOD (v294.2)
A		e8u4vA1	A: beta barrels	X: RNase A-like	H: RNase A-like	T: RNase A-like	F:	ECOD (v294.2)

SAbDab Antibody Annotation SAbDab Database Homepage

Chain	Chain Class	Chain Subclass	Chain Type	Antigen Name(s)	Provenance Source
E [auth K]	Heavy Chain	IGHV1	-	-	SAbDab (2026-05-08)
D [auth H]	Heavy Chain	IGHV3	-	claudin-4 \| heat-labile enterotoxin b chain	SAbDab (2026-05-08)
C [auth L]	Light Chain	IGKV1	Kappa	claudin-4 \| heat-labile enterotoxin b chain	SAbDab (2026-05-08)

Gene Ontology: Gene Product Annotation Gene Ontology Database Homepage

Chains	Polymer	Molecular Function	Biological Process	Cellular Component
E [auth K]	Anti-fab nanobody	-	-	-
D [auth H]	COP-1 sFab Heavy Chain	-	-	-
C [auth L]	COP-1 sFab Light Chain	-	-	-
B	Heat-labile enterotoxin B chain	toxin activity	-	cellular anatomical structure extracellular region
A	Claudin-4	monoatomic anion transmembrane transporter activity chloride transmembrane transporter activity passive transmembrane transporter activity monoatomic ion channel activity channel activity monoatomic anion channel activity monoatomic ion transmembrane transporter activity transporter activity transmembrane transporter activity chloride channel activity structural molecule activity identical protein binding protein binding binding monoatomic anion transmembrane transporter activity chloride transmembrane transporter activity passive transmembrane transporter activity monoatomic ion channel activity channel activity monoatomic anion channel activity monoatomic ion transmembrane transporter activity transporter activity transmembrane transporter activity chloride channel activity structural molecule activity identical protein binding protein binding binding molecular transducer activity transmembrane signaling receptor activity signaling receptor activity	rhythmic process circadian rhythm calcium-independent cell-cell adhesion cell adhesion cell-cell adhesion cellular process positive regulation of response to wounding wound healing regulation of biological process response to stimulus biological regulation positive regulation of biological process regulation of response to wounding positive regulation of response to stimulus rhythmic process circadian rhythm calcium-independent cell-cell adhesion cell adhesion cell-cell adhesion cellular process positive regulation of response to wounding wound healing regulation of biological process response to stimulus biological regulation positive regulation of biological process regulation of response to wounding positive regulation of response to stimulus positive regulation of wound healing regulation of response to stimulus response to stress regulation of response to stress regulation of wound healing response to wounding multi-multicellular organism process multicellular organismal process reproductive process female pregnancy multi-organism reproductive process response to ketone response to lipid response to hormone response to steroid hormone response to chemical response to endogenous stimulus response to progesterone response to oxygen-containing compound developmental process establishment of skin barrier epithelium development skin development skin epidermis development epidermis development anatomical structure development animal organ development tissue development anatomical structure morphogenesis regulation of developmental process cell morphogenesis regulation of cell morphogenesis regulation of anatomical structure morphogenesis bicellular tight junction assembly tight junction organization apical junction assembly cellular component organization cellular component biogenesis cell junction organization cellular component assembly cell junction assembly tight junction assembly cellular component organization or biogenesis cell-cell junction assembly cell-cell junction organization renal system process system process renal absorption positive regulation of locomotion regulation of cell motility regulation of cellular process positive regulation of cell migration regulation of locomotion positive regulation of cell motility regulation of cell migration cell migration cell motility locomotion positive regulation of cellular process localization transport paracellular transport establishment of localization	protein-containing complex cellular anatomical structure transmembrane transporter complex membrane chloride channel complex membrane protein complex transporter complex monoatomic ion channel complex cell-cell junction anchoring junction cell junction cell periphery apical part of cell plasma membrane protein-containing complex cellular anatomical structure transmembrane transporter complex membrane chloride channel complex membrane protein complex transporter complex monoatomic ion channel complex cell-cell junction anchoring junction cell junction cell periphery apical part of cell plasma membrane plasma membrane region apical plasma membrane basal part of cell basal plasma membrane apicolateral plasma membrane apical junction complex bicellular tight junction tight junction lateral plasma membrane

InterPro: Protein Family Classification InterPro Database Homepage

Chains	Accession	Name	Type
B	IPR003897	Clostridium enterotoxin	Family
A	IPR006187	Claudin	Family
A	IPR004031	PMP-22/EMP/MP20/Claudin	Family
A	IPR017974	Claudin, conserved site	Conserved Site
A	IPR003550	Claudin-4	Family

Pharos: Disease Associations Pharos Homepage Annotation

Chains	Drug Target	Associated Disease
A	: O14493	polycystic ovary syndrome invasive ductal breast carcinoma breast carcinoma Neoplasm Recurrence, Local breast cancer gastric carcinoma lung adenocarcinoma malignant pancreatic neoplasm ovarian cancer Williams syndrome interstitial cystitis malignant mesothelioma pancreatic intraductal papillary-mucinous carcinoma ductal breast carcinoma in situ osteosarcoma polycystic ovary syndrome invasive ductal breast carcinoma breast carcinoma Neoplasm Recurrence, Local breast cancer gastric carcinoma lung adenocarcinoma malignant pancreatic neoplasm ovarian cancer Williams syndrome interstitial cystitis malignant mesothelioma pancreatic intraductal papillary-mucinous carcinoma ductal breast carcinoma in situ osteosarcoma pancreatic intraductal papillary-mucinous neoplasm

Membrane Protein Annotation: PDBTM PDBTM Database Homepage

Chains	External Link	Comment
A	PDBTM	Annotated as membrane protein by PDBTM

Membrane Protein Annotation: mpstruc mpstruc Database Homepage

Chains	Resource Link	Group	Subgroup	Protein
A	mpstruc	TRANSMEMBRANE PROTEINS: ALPHA-HELICAL	Claudins	Claudin-4 in complex with Clostridium perfringens enterotoxin C-terminal domain and sFab COP-1

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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.