Annotations: 5T1M

Cetuximab Fab in complex with CQYDLSTRRLKC

External Resource: Annotation

Domain Annotation: ECOD Classification
Domain Annotation: CATH
IMGT Antibody Annotation
SAbDab Antibody Annotation
Thera-SAbDab Antibody Annotation
Protein Modification Annotation

Domain Annotation: ECOD Classification ECOD Database Homepage

Chains	Family Name	Domain Identifier	Architecture	Possible Homology	Homology	Topology	Family	Provenance Source (Version)
B	Fer4+Fer4_7	e5t1mB1	A: beta barrels	X: Sulfite reductase hemoprotein (SiRHP), domains 2 and 4	H: Sulfite reductase hemoprotein (SiRHP), domains 2 and 4	T: Sulfite reductase hemoprotein (SiRHP), domains 2 and 4	F: Fer4+Fer4_7	ECOD (v294.2)
D	Fer4+Fer4_7	e5t1mD1	A: beta barrels	X: Sulfite reductase hemoprotein (SiRHP), domains 2 and 4	H: Sulfite reductase hemoprotein (SiRHP), domains 2 and 4	T: Sulfite reductase hemoprotein (SiRHP), domains 2 and 4	F: Fer4+Fer4_7	ECOD (v294.2)
A	Fer4+Fer4_7	e5t1mA1	A: beta barrels	X: Sulfite reductase hemoprotein (SiRHP), domains 2 and 4	H: Sulfite reductase hemoprotein (SiRHP), domains 2 and 4	T: Sulfite reductase hemoprotein (SiRHP), domains 2 and 4	F: Fer4+Fer4_7	ECOD (v294.2)
C	Fer4+Fer4_7	e5t1mC1	A: beta barrels	X: Sulfite reductase hemoprotein (SiRHP), domains 2 and 4	H: Sulfite reductase hemoprotein (SiRHP), domains 2 and 4	T: Sulfite reductase hemoprotein (SiRHP), domains 2 and 4	F: Fer4+Fer4_7	ECOD (v294.2)

Domain Annotation: CATH CATH Database Homepage

Chain	Domain	Class	Architecture	Topology	Homology	Provenance Source (Version)
B	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
D	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
A	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
C	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
B, D	Cetuximab Fab	VH-CH1	Chimeric (chimeric)	IGHV2-203, IGHJ301, IGHG1*03	V-DOMAIN VH, C-DOMAIN CH1	IG	FAB-GAMMA-1_KAPPA	IMGT (202617-0)
A, C	Cetuximab Fab	L-KAPPA	Chimeric (chimeric)	IGKV5-4801, IGKJ501, IGKJ2-301, IGKJ2-101, IGKJ2-201, IGKC01	V-DOMAIN V-KAPPA, C-DOMAIN C-KAPPA	IG	FAB-GAMMA-1_KAPPA	IMGT (202617-0)

SAbDab Antibody Annotation SAbDab Database Homepage

Chain	Chain Class	Chain Subclass	Chain Type	Antigen Name(s)	Provenance Source
B, D	Heavy Chain	IGHV2	-	-	SAbDab (2026-05-08)
A, C	Light Chain	IGKV5	Kappa	-	SAbDab (2026-05-08)

Thera-SAbDab Antibody Annotation Thera-SAbDab Database Homepage

Chain	Name	Target	Provenance Source
B, D	Tomuzotuximab	EGFR/ERBB1/HER1, ERBB3/HER3	Therapeutic SAbDab (2026-05-08)
A, C	Cetuximab	EGFR/ERBB1/HER1, ERBB3/HER3	Therapeutic SAbDab (2026-05-08)

Protein Modification Annotation

Modified Residue(s)
Chain	Residue(s)	Description
B, D	PCA	Parent Component: GLN : AA0031 : 2-pyrrolidone-5-carboxylic acid (Gln) MOD:00040 , 2-pyrrolidone-5-carboxylic acid (Glu) MOD:00420

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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.