4NP4 | pdb_00004np4

Clostridium difficile toxin B CROP domain in complex with FAB domains of neutralizing antibody bezlotoxumab

External Resource: Annotation

Domain Annotation: SCOP/SCOPe Classification
Domain Annotation: ECOD Classification
Domain Annotation: CATH
IMGT Antibody Annotation
SAbDab Antibody Annotation
Thera-SAbDab Antibody Annotation
Gene Ontology: Gene Product Annotation
InterPro: Protein Family Classification

Domain Annotation: SCOP/SCOPe Classification SCOP-e Database Homepage

Chains	Domain Info	Class	Fold	Superfamily	Family	Domain	Species	Provenance Source (Version)
E [auth M]	d4np4m1	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	V set domains (antibody variable domain-like)	automated matches	(Homo sapiens ) [TaxId: 9606 ],	SCOPe (2.08)
E [auth M]	d4np4m2	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	C1 set domains (antibody constant domain-like)	automated matches	(Homo sapiens ) [TaxId: 9606 ],	SCOPe (2.08)
D [auth L]	d4np4l1	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	V set domains (antibody variable domain-like)	automated matches	(Homo sapiens ) [TaxId: 9606 ],	SCOPe (2.08)
D [auth L]	d4np4l2	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	C1 set domains (antibody constant domain-like)	automated matches	(Homo sapiens ) [TaxId: 9606 ],	SCOPe (2.08)
C [auth I]	d4np4i_	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	automated matches	automated matches	(Homo sapiens ) [TaxId: 9606 ],	SCOPe (2.08)
B [auth H]	d4np4h_	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	automated matches	automated matches	(Homo sapiens ) [TaxId: 9606 ],	SCOPe (2.08)

Domain Annotation: ECOD Classification ECOD Database Homepage

Chains	Family Name	Domain Identifier	Architecture	Possible Homology	Homology	Topology	Family	Provenance Source (Version)
E [auth M]		e4np4M1	A: HTH	X: Toll/Interleukin receptor TIR domain	H: Toll/Interleukin receptor TIR domain	T: PemK_toxin	F:	ECOD (20:10:01)
D [auth L]		e4np4L1	A: HTH	X: Toll/Interleukin receptor TIR domain	H: Toll/Interleukin receptor TIR domain	T: PemK_toxin	F:	ECOD (20:10:01)
C [auth I]		e4np4I1	A: HTH	X: Toll/Interleukin receptor TIR domain	H: Toll/Interleukin receptor TIR domain	T: PemK_toxin	F:	ECOD (20:10:01)
B [auth H]		e4np4H1	A: HTH	X: Toll/Interleukin receptor TIR domain	H: Toll/Interleukin receptor TIR domain	T: PemK_toxin	F:	ECOD (20:10:01)
A		e4np4A1	A: HTH	X: Toll/Interleukin receptor TIR domain	H: Toll/Interleukin receptor TIR domain	T: PemK_toxin	F:	ECOD (20:10:01)

Domain Annotation: CATH CATH Database Homepage

Chain	Domain	Class	Architecture	Topology	Homology	Provenance Source (Version)
E [auth M]	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
D [auth L]	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
C [auth I]	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
B [auth H]	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)

IMGT Antibody Annotation IMGT Database Homepage

Chain	Protein Name	Description	Organism Name	Gene Allele Name(s)	Domain Name(s)	Receptor Type	Receptor Description	Provenance Source
D [auth L], E [auth M]	INN name	L-KAPPA	Homo sapiens (human)	IGKV3-2001, IGKJ101, IGKC*01	V-DOMAIN V-KAPPA, C-DOMAIN C-KAPPA	IG	FAB-GAMMA-1_KAPPA	IMGT (202609-0)
B [auth H], C [auth I]	INN name	VH-CH1	Homo sapiens (human)	IGHV5-5101, IGHV5-5103, IGHJ302, IGHG103	V-DOMAIN VH, C-DOMAIN CH1	IG	FAB-GAMMA-1_KAPPA	IMGT (202609-0)

SAbDab Antibody Annotation SAbDab Database Homepage

Chain	Chain Class	Chain Subclass	Chain Type	Antigen Name(s)	Provenance Source
D [auth L], E [auth M]	Light Chain	IGKV3	Kappa	toxin b	SAbDab (2026-03-13)
B [auth H], C [auth I]	Heavy Chain	IGHV5	-	toxin b	SAbDab (2026-03-13)

Thera-SAbDab Antibody Annotation Thera-SAbDab Database Homepage

Chain	Name	Target	Provenance Source
D [auth L], E [auth M]	Bezlotoxumab	Clostridium difficile Toxin A	Therapeutic SAbDab (2026-03-13)
B [auth H], C [auth I]	Bezlotoxumab	Clostridium difficile Toxin A	Therapeutic SAbDab (2026-03-13)

Gene Ontology: Gene Product Annotation Gene Ontology Database Homepage

Chains	Polymer	Molecular Function	Biological Process	Cellular Component
D [auth L], E [auth M]	bezlotoxumab light chain	-	-	-
B [auth H], C [auth I]	bezlotoxumab heavy chain	-	-	-
A	Toxin B	binding lipid binding toxin activity glycosyltransferase activity transferase activity glucosyltransferase activity hexosyltransferase activity catalytic activity cysteine-type peptidase activity peptidase activity catalytic activity, acting on a protein hydrolase activity cation binding ion binding binding lipid binding toxin activity glycosyltransferase activity transferase activity glucosyltransferase activity hexosyltransferase activity catalytic activity cysteine-type peptidase activity peptidase activity catalytic activity, acting on a protein hydrolase activity cation binding ion binding metal ion binding small molecule binding	symbiont-mediated perturbation of host actin cytoskeleton symbiont-mediated disruption of host anatomical structure biological process involved in interspecies interaction between organisms symbiont-mediated perturbation of host actin cytoskeleton via filamentous actin depolymerization symbiont-mediated perturbation of host cytoskeleton disruption of anatomical structure in another organism symbiont-mediated disruption of host cellular anatomical structure proteolysis metabolic process cellular process primary metabolic process protein metabolic process macromolecule metabolic process	cellular anatomical structure extracellular region host intracellular membrane-bounded organelle host cellular component host intracellular part host cell membrane other organism part host cell cytoplasm part host intracellular organelle host cell endosome membrane host cell cytoplasm host cell part host cell endosome host intracellular region cellular anatomical structure extracellular region host intracellular membrane-bounded organelle host cellular component host intracellular part host cell membrane other organism part host cell cytoplasm part host intracellular organelle host cell endosome membrane host cell cytoplasm host cell part host cell endosome host intracellular region host cell plasma membrane host cell cytosol

InterPro: Protein Family Classification InterPro Database Homepage

Chains	Accession	Name	Type
A	IPR038383	CGT/MARTX, cysteine protease (CPD) domain superfamily	Homologous Superfamily
A	IPR024772	TcdA/TcdB toxin, N-terminal helical domain	Domain
A	IPR020974	CGT/MARTX, cysteine protease (CPD) domain	Domain
A	IPR024769	TcdA/TcdB toxin, pore forming domain	Domain
A	IPR029044	Nucleotide-diphospho-sugar transferases	Homologous Superfamily
A	IPR024770	TcdA/TcdB toxin, catalytic glycosyltransferase domain	Domain
A	IPR018337	Cell wall/choline-binding repeat	Repeat

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.