Annotations: 3IU3

Crystal structure of the Fab fragment of therapeutic antibody Basiliximab in complex with IL-2Ra (CD25) ectodomain

External Resource: Annotation

Domain Annotation: ECOD Classification
Domain Annotation: CATH
IMGT Antibody Annotation
SAbDab Antibody Annotation
Thera-SAbDab Antibody Annotation
Protein Family Annotation
Gene Ontology: Gene Product Annotation
InterPro: Protein Family Classification
Pharos: Disease Associations

Domain Annotation: ECOD Classification ECOD Database Homepage

Chains	Family Name	Domain Identifier	Architecture	Possible Homology	Homology	Topology	Family	Provenance Source (Version)
I [auth K]	adh_short	e3iu3K1	A: alpha arrays	X: Alpha-beta plaits	H: Phage tail protein-like	T: Transmembrane protein 14A	F: adh_short	ECOD (v295.2)
H [auth J]	adh_short	e3iu3J1	A: alpha arrays	X: Alpha-beta plaits	H: Phage tail protein-like	T: Transmembrane protein 14A	F: adh_short	ECOD (v295.2)
G [auth I]		e3iu3I3	A: alpha arrays	X: DEATH domain	H: PH domain-like	T: PH domain-like	F:	ECOD (v295.2)
F [auth L]	adh_short	e3iu3L1	A: alpha arrays	X: Alpha-beta plaits	H: Phage tail protein-like	T: Transmembrane protein 14A	F: adh_short	ECOD (v295.2)
D	adh_short	e3iu3D1	A: alpha arrays	X: Alpha-beta plaits	H: Phage tail protein-like	T: Transmembrane protein 14A	F: adh_short	ECOD (v295.2)
B	adh_short	e3iu3B1	A: alpha arrays	X: Alpha-beta plaits	H: Phage tail protein-like	T: Transmembrane protein 14A	F: adh_short	ECOD (v295.2)
E [auth H]	adh_short	e3iu3H1	A: alpha arrays	X: Alpha-beta plaits	H: Phage tail protein-like	T: Transmembrane protein 14A	F: adh_short	ECOD (v295.2)
C	adh_short	e3iu3C1	A: alpha arrays	X: Alpha-beta plaits	H: Phage tail protein-like	T: Transmembrane protein 14A	F: adh_short	ECOD (v295.2)
A	SUFU	e3iu3A1	A: alpha arrays	X: EGF-like	H: EGF-related	T: EGF/Laminin	F: SUFU	ECOD (v295.2)

Domain Annotation: CATH CATH Database Homepage

Chain	Domain	Class	Architecture	Topology	Homology	Provenance Source (Version)
I [auth K]	2.10.70.10	Mainly Beta	Ribbon	Complement Module	domain 1	CATH (4.3.0)
I [auth K]	2.20.28.230	Mainly Beta	Single Sheet	Rubrerythrin, domain 2		CATH (4.3.0)
H [auth J]	2.10.70.10	Mainly Beta	Ribbon	Complement Module	domain 1	CATH (4.3.0)
H [auth J]	2.20.28.230	Mainly Beta	Single Sheet	Rubrerythrin, domain 2		CATH (4.3.0)
G [auth I]	2.10.70.10	Mainly Beta	Ribbon	Complement Module	domain 1	CATH (4.3.0)
G [auth I]	2.20.28.230	Mainly Beta	Single Sheet	Rubrerythrin, domain 2		CATH (4.3.0)
F [auth L]	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)
B	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
E [auth H]	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)
A	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, F [auth L]	basiliximab	L-KAPPA	Chimeric (chimeric)	IGKV4-7001, IGKJ101, IGKJ102, IGKJ201, IGKC*01	V-DOMAIN V-KAPPA, C-DOMAIN C-KAPPA	IG	FAB-GAMMA-1_KAPPA	IMGT (202640-0)
A, C, E [auth H]	basiliximab	VH-CH1	Chimeric (chimeric)	IGHV1-501, IGHJ201, IGHG1*03	V-DOMAIN VH, C-DOMAIN CH1	IG	FAB-GAMMA-1_KAPPA	IMGT (202640-0)

SAbDab Antibody Annotation SAbDab Database Homepage

Chain	Chain Class	Chain Subclass	Chain Type	Antigen Name(s)	Provenance Source
B, D, F [auth L]	Light Chain	IGKV4	Kappa	interleukin-2 receptor alpha chain	SAbDab (2026-10-16)
A, C, E [auth H]	Heavy Chain	IGHV1	-	interleukin-2 receptor alpha chain	SAbDab (2026-10-16)

Thera-SAbDab Antibody Annotation Thera-SAbDab Database Homepage

Chain	Name	Target	Provenance Source
B, D, F [auth L]	Basiliximab	IL2RA/CD25	Therapeutic SAbDab (2026-10-16)
A, C, E [auth H]	Basiliximab	IL2RA/CD25	Therapeutic SAbDab (2026-10-16)

Protein Family Annotation Pfam Database Homepage

Chains	Accession	Name	Description	Comments	Source
G [auth I], H [auth J], I [auth K]	PF00084	Sushi repeat (SCR repeat) (Sushi)	Sushi repeat (SCR repeat)		Domain
B, D, F [auth L]	PF07654	Immunoglobulin C1-set domain (C1-set)	Immunoglobulin C1-set domain		Domain

Gene Ontology: Gene Product Annotation Gene Ontology Database Homepage

Chains	Polymer	Molecular Function	Biological Process	Cellular Component
G [auth I], H [auth J], I [auth K]	Interleukin-2 receptor alpha chain	protein binding binding growth factor binding cytokine binding interleukin-2 binding molecular transducer activity interleukin-2 receptor activity transmembrane signaling receptor activity signaling receptor activity cytokine receptor activity immune receptor activity	cellular response to stimulus cell surface receptor signaling pathway via STAT regulation of biological process regulation of cellular process cell surface receptor signaling pathway response to stimulus signaling biological regulation cell communication cellular process signal transduction cell surface receptor signaling pathway via JAK-STAT multicellular organismal process positive regulation of cell population proliferation cellular response to stimulus cell surface receptor signaling pathway via STAT regulation of biological process regulation of cellular process cell surface receptor signaling pathway response to stimulus signaling biological regulation cell communication cellular process signal transduction cell surface receptor signaling pathway via JAK-STAT multicellular organismal process positive regulation of cell population proliferation regulation of leukocyte activation regulation of cell activation positive regulation of cell activation T cell activation lymphocyte proliferation positive regulation of leukocyte activation regulation of immune system process positive regulation of immune system process regulation of leukocyte proliferation cell population proliferation positive regulation of T cell activation positive regulation of lymphocyte proliferation positive regulation of T cell proliferation positive regulation of activated T cell proliferation regulation of cell population proliferation mononuclear cell proliferation regulation of leukocyte cell-cell adhesion positive regulation of leukocyte proliferation positive regulation of multicellular organismal process regulation of activated T cell proliferation positive regulation of biological process positive regulation of leukocyte cell-cell adhesion lymphocyte activation leukocyte proliferation leukocyte cell-cell adhesion leukocyte activation activated T cell proliferation positive regulation of cell-cell adhesion positive regulation of lymphocyte activation cell adhesion cell-cell adhesion positive regulation of mononuclear cell proliferation regulation of multicellular organismal process regulation of cell-cell adhesion positive regulation of cellular process T cell proliferation regulation of lymphocyte proliferation positive regulation of cell adhesion regulation of cell adhesion cell activation regulation of T cell activation regulation of T cell proliferation immune system process regulation of mononuclear cell proliferation regulation of lymphocyte activation regulation of leukocyte differentiation regulation of developmental process cellular developmental process cell development regulation of cell differentiation regulation of cell development positive regulation of developmental process multicellular organism development positive regulation of hemopoiesis positive regulation of cell differentiation cell differentiation anatomical structure development developmental process regulation of multicellular organismal development hemopoiesis positive regulation of cell development regulation of hemopoiesis positive regulation of leukocyte differentiation leukocyte differentiation defense response immune response response to stress inflammatory response inflammatory response to antigenic stimulus interleukin-2-mediated signaling pathway cellular response to interleukin-2 response to cytokine cytokine-mediated signaling pathway response to peptide response to interleukin-2 response to chemical cellular response to cytokine stimulus apoptotic process cell death programmed cell death immune system development T cell tolerance induction regulation of tolerance induction regulation of T cell tolerance induction animal gross anatomical part developmental process tolerance induction system development mononuclear cell differentiation lymphocyte differentiation positive regulation of T cell differentiation T cell differentiation regulation of T cell differentiation regulation of lymphocyte differentiation positive regulation of lymphocyte differentiation	cell periphery cellular anatomical structure cell surface membrane plasma membrane external side of plasma membrane side of membrane protein-containing complex plasma membrane protein complex plasma membrane signaling receptor complex membrane protein complex signaling receptor complex interleukin-2 receptor complex
B, D, F [auth L]	Light chain of Fab fragment of Basiliximab	-	-	-
A, C, E [auth H]	Heavy chain of Fab fragment of Basiliximab	-	-	-

InterPro: Protein Family Classification InterPro Database Homepage

Chains	Accession	Name	Type
G [auth I], H [auth J], I [auth K]	IPR015486	Interleukin-2 receptor alpha	Family
G [auth I], H [auth J], I [auth K]	IPR000436	Sushi/SCR/CCP domain	Domain
G [auth I], H [auth J], I [auth K]	IPR035976	Sushi/SCR/CCP superfamily	Homologous Superfamily

Pharos: Disease Associations Pharos Homepage Annotation

Chains	Drug Target	Associated Disease
G [auth I], H [auth J], I [auth K]	: P01589	rheumatoid arthritis immunodeficiency due to CD25 deficiency Crohn disease alopecia areata HIV infectious disease juvenile idiopathic arthritis type 1 diabetes mellitus glomerulonephritis type 1 diabetes mellitus 10 multiple sclerosis oligoarticular juvenile idiopathic arthritis malignant mesothelioma chronic beryllium disease schizophrenia allergic contact dermatitis rheumatoid arthritis immunodeficiency due to CD25 deficiency Crohn disease alopecia areata HIV infectious disease juvenile idiopathic arthritis type 1 diabetes mellitus glomerulonephritis type 1 diabetes mellitus 10 multiple sclerosis oligoarticular juvenile idiopathic arthritis malignant mesothelioma chronic beryllium disease schizophrenia allergic contact dermatitis Diabetes Mellitus, Insulin-Dependent Graves disease sclerosing cholangitis acquired metabolic disease allergic rhinitis major depressive disorder atopic eczema psoriasis relapsing-remitting multiple sclerosis glioblastoma rheumatoid factor-negative juvenile idiopathic arthritis Hashimoto thyroiditis hypothyroidism vitiligo inflammatory bowel disease acute myeloid leukemia large cell medulloblastoma atypical teratoid rhabdoid tumor neuroblastoma Crohn's colitis ovarian cancer diabetes mellitus ileocolitis interstitial cystitis lung adenocarcinoma asthma marginal zone lymphoma autoimmune disease non-small cell lung carcinoma common variable immunodeficiency primary cutaneous T-cell lymphoma