4NC1 | pdb_00004nc1

Crystal Structure of TcdA-A2 Bound to A20.1 VHH and A26.8 VHH

External Resource: Annotation

Domain Annotation: SCOP/SCOPe Classification
Domain Annotation: ECOD Classification
Domain Annotation: CATH
IMGT Antibody Annotation
SAbDab Antibody Annotation

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

Chains	Domain Info	Class	Fold	Superfamily	Family	Domain	Species	Provenance Source (Version)
C [auth E]	d4nc1e1	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	V set domains (antibody variable domain-like)	automated matches	(Lama glama ) [TaxId: 9844 ],	SCOPe (2.08)
C [auth E]	d4nc1e2	Artifacts	Tags	Tags	Tags	C-terminal Tags	(Lama glama ) [TaxId: 9844 ],	SCOPe (2.08)
F	d4nc1f1	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	V set domains (antibody variable domain-like)	automated matches	(Lama glama ) [TaxId: 9844 ],	SCOPe (2.08)
F	d4nc1f2	Artifacts	Tags	Tags	Tags	C-terminal Tags	(Lama glama ) [TaxId: 9844 ],	SCOPe (2.08)
B [auth C]	d4nc1c_	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	V set domains (antibody variable domain-like)	automated matches	(Lama glama ) [TaxId: 9844 ],	SCOPe (2.08)
E [auth D]	d4nc1d_	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	V set domains (antibody variable domain-like)	automated matches	(Lama glama ) [TaxId: 9844 ],	SCOPe (2.08)

Domain Annotation: ECOD Classification ECOD Database Homepage

Chains	Family Name	Domain Identifier	Architecture	Possible Homology	Homology	Topology	Family	Provenance Source (Version)
C [auth E]	EF-hand_1,S_100	e4nc1E1	A: a/b three-layered sandwiches	X: dsRBD-like	H: Peptidyl-tRNA hydrolase domain-like	T: Peptidyl-tRNA hydrolase domain-like	F: EF-hand_1,S_100	ECOD (v294.1)
F	EF-hand_1,S_100	e4nc1F1	A: a/b three-layered sandwiches	X: dsRBD-like	H: Peptidyl-tRNA hydrolase domain-like	T: Peptidyl-tRNA hydrolase domain-like	F: EF-hand_1,S_100	ECOD (v294.1)
B [auth C]	EF-hand_1,S_100	e4nc1C1	A: a/b three-layered sandwiches	X: dsRBD-like	H: Peptidyl-tRNA hydrolase domain-like	T: Peptidyl-tRNA hydrolase domain-like	F: EF-hand_1,S_100	ECOD (v294.1)
E [auth D]	EF-hand_1,S_100	e4nc1D1	A: a/b three-layered sandwiches	X: dsRBD-like	H: Peptidyl-tRNA hydrolase domain-like	T: Peptidyl-tRNA hydrolase domain-like	F: EF-hand_1,S_100	ECOD (v294.1)
A	ERG4_ERG24	e4nc1A2	A: a/b three-layered sandwiches	X: Immunoglobulin-like beta-sandwich	H: Immunoglobulin-related	T: N-terminal domain of Delta(14)-sterol reductase, MaSR1	F: ERG4_ERG24	ECOD (v294.1)
D [auth B]		e4nc1B1	A: a/b three-layered sandwiches	X: Rossmann-like	H: Rossmann-related	T: Nucleotide-binding domain	F:	ECOD (v294.1)

Domain Annotation: CATH CATH Database Homepage

Chain	Domain	Class	Architecture	Topology	Homology	Provenance Source (Version)
C [auth E]	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
F	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
B [auth C]	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
E [auth D]	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
D [auth B]	2.10.270.10	Mainly Beta	Ribbon	left handed beta-beta-3-solenoid	Cholin Binding	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
C [auth E], F	A26.8 VHH	VH	Lama glama (llama)	IGHV3S101, IGHJ401	V-DOMAIN VH	IG	(VH)	IMGT (202611-0)
B [auth C], E [auth D]	A20.1 VHH	VH	Lama glama (llama)	IGHV3S301, IGHJ401	V-DOMAIN VH	IG	(VH)	IMGT (202611-0)

SAbDab Antibody Annotation SAbDab Database Homepage

Chain	Chain Class	Chain Subclass	Chain Type	Antigen Name(s)	Provenance Source
C [auth E], F	Heavy Chain	IGHV1	-	cell wall-binding repeat protein	SAbDab (2026-03-27)
B [auth C], E [auth D]	Heavy Chain	IGHV1	-	cell wall-binding repeat protein	SAbDab (2026-03-27)

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.