Annotations: 3QIU

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

Chains	Domain Info	Class	Fold	Superfamily	Family	Domain	Species	Provenance Source (Version)
A	d3qiua2	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	C1 set domains (antibody constant domain-like)	automated matches	mouse (Mus musculus ) [TaxId: 10090 ],	SCOPe (2.08)
A	d3qiua1	Alpha and beta proteins (a+b)	MHC antigen-recognition domain	MHC antigen-recognition domain	automated matches	automated matches	mouse (Mus musculus ) [TaxId: 10090 ],	SCOPe (2.08)
B	d3qiub2	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	C1 set domains (antibody constant domain-like)	Class II MHC beta chain, C-terminal domain	mouse (Mus musculus ) [TaxId: 10090 ],	SCOPe (2.08)
B	d3qiub1	Alpha and beta proteins (a+b)	MHC antigen-recognition domain	MHC antigen-recognition domain	automated matches	automated matches	mouse (Mus musculus ) [TaxId: 10090 ],	SCOPe (2.08)
C	d3qiuc2	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	C1 set domains (antibody constant domain-like)	automated matches	mouse (Mus musculus ) [TaxId: 10090 ],	SCOPe (2.08)
C	d3qiuc1	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	automated matches	automated matches	mouse (Mus musculus ) [TaxId: 10090 ],	SCOPe (2.08)
D	d3qiud2	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	C1 set domains (antibody constant domain-like)	automated matches	mouse (Mus musculus ) [TaxId: 10090 ],	SCOPe (2.08)
D	d3qiud1	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	automated matches	automated matches	mouse (Mus musculus ) [TaxId: 10090 ],	SCOPe (2.08)

Domain Annotation: SCOP2 Classification SCOP2 Database Homepage

Chains	Type	Family Name	Domain Identifier	Family Identifier	Provenance Source (Version)
A	SCOP2B Superfamily	MHC antigen-recognition domain	8033118	3000521	SCOP2B (2022-06-29)
A	SCOP2B Superfamily	Immunoglobulin (Ig) domain-like	8054673	3000071	SCOP2B (2022-06-29)
B	SCOP2B Superfamily	Immunoglobulin (Ig) domain-like	8054713	3000071	SCOP2B (2022-06-29)
B	SCOP2B Superfamily	MHC antigen-recognition domain	8055626	3000521	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)
A	PF07654	e3qiuA1	A: beta sandwiches	X: Immunoglobulin-like beta-sandwich	H: Immunoglobulin-related	T: Immunoglobulin/Fibronectin type III/E set domains/PapD-like	F: PF07654	ECOD (1.6)
A	PF00993	e3qiuA2	A: a+b two layers	X: MHC antigen-recognition domain (From Topology)	H: MHC antigen-recognition domain (From Topology)	T: MHC antigen-recognition domain	F: PF00993	ECOD (1.6)
B	PF07654	e3qiuB1	A: beta sandwiches	X: Immunoglobulin-like beta-sandwich	H: Immunoglobulin-related	T: Immunoglobulin/Fibronectin type III/E set domains/PapD-like	F: PF07654	ECOD (1.6)
B	PF00969	e3qiuB2	A: a+b two layers	X: MHC antigen-recognition domain (From Topology)	H: MHC antigen-recognition domain (From Topology)	T: MHC antigen-recognition domain	F: PF00969	ECOD (1.6)
C	PF07686	e3qiuC3	A: beta sandwiches	X: Immunoglobulin-like beta-sandwich	H: Immunoglobulin-related	T: Immunoglobulin/Fibronectin type III/E set domains/PapD-like	F: PF07686	ECOD (1.6)
C	PF09291	e3qiuC4	A: beta sandwiches	X: Immunoglobulin-like beta-sandwich	H: Immunoglobulin-related	T: Immunoglobulin/Fibronectin type III/E set domains/PapD-like	F: PF09291	ECOD (1.6)
D	PF07654	e3qiuD3	A: beta sandwiches	X: Immunoglobulin-like beta-sandwich	H: Immunoglobulin-related	T: Immunoglobulin/Fibronectin type III/E set domains/PapD-like	F: PF07654	ECOD (1.6)
D	PF07686	e3qiuD4	A: beta sandwiches	X: Immunoglobulin-like beta-sandwich	H: Immunoglobulin-related	T: Immunoglobulin/Fibronectin type III/E set domains/PapD-like	F: PF07686	ECOD (1.6)

Domain Annotation: CATH CATH Database Homepage

Chain	Domain	Class	Architecture	Topology	Homology	Provenance Source (Version)
A	3.10.320.10	Alpha Beta	Roll	Class II Histocompatibility Antigen, M Beta Chain	Chain B, domain 1	CATH (4.3.0)
A	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
B	3.10.320.10	Alpha Beta	Roll	Class II Histocompatibility Antigen, M Beta Chain	Chain B, domain 1	CATH (4.3.0)
B	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)
D	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
A	MH2-EAk_MH2-EB1k	II-ALPHA	Mus musculus (house mouse)	MH2-AAe, H2-EAck, H2-EAk	G-DOMAIN G-ALPHA, C-LIKE-DOMAIN C-LIKE	MH	MH2-ALPHA_BETA	IMGT (202416-0)
B	MH2-EAk_MH2-EB1k	II-BETA	Mus musculus (house mouse)	H2-EB1k	G-DOMAIN G-BETA, C-LIKE-DOMAIN C-LIKE	MH	MH2-ALPHA_BETA	IMGT (202416-0)
C	TR 226	TR-ALPHA	Chimeric (chimeric)	TRAV4D-403, TRAV4N-401, TRAJ1601, TRAC01	V-DOMAIN V-ALPHA, C-DOMAIN C-ALPHA	TR	TR-ALPHA_BETA-2	IMGT (202416-0)
D	TR 226	TR-BETA-2	Chimeric (chimeric)	TRBV2601, TRBJ1-201, TRBC201, TRBC202	V-DOMAIN V-BETA, C-DOMAIN C-BETA-2	TR	TR-ALPHA_BETA-2	IMGT (202416-0)

Protein Family Annotation Pfam Database Homepage

Chains	Accession	Name	Description	Comments	Source
A	PF07654	Immunoglobulin C1-set domain (C1-set)	Immunoglobulin C1-set domain	-	Domain
A	PF00993	Class II histocompatibility antigen, alpha domain (MHC_II_alpha)	Class II histocompatibility antigen, alpha domain	-	Domain
B	PF00969	Class II histocompatibility antigen, beta domain (MHC_II_beta)	Class II histocompatibility antigen, beta domain	-	Domain
B	PF07654	Immunoglobulin C1-set domain (C1-set)	Immunoglobulin C1-set domain	-	Domain
E	PF00034	Cytochrome c (Cytochrom_C)	Cytochrome c	The Pfam entry does not include all Prosite members. The cytochrome 556 and cytochrome c' families are not included. All these are now in a new clan together. The C-terminus of DUF989, Pfam:PF06181, has now been merged into this family.	Domain

Gene Ontology: Gene Product Annotation Gene Ontology Database Homepage

Chains	Polymer	Molecular Function	Biological Process	Cellular Component
A	H-2 CLASS II HISTOCOMPATIBILITY ANTIGEN, E-K alpha chain	binding antigen binding peptide antigen binding peptide binding protein-containing complex binding MHC protein complex binding MHC class II protein complex binding	regulation of biological process response to stimulus immune response biological regulation positive regulation of biological process positive regulation of response to stimulus positive regulation of immune response regulation of response to stimulus immune system process regulation of immune response regulation of immune system process positive regulation of immune system process peptide antigen assembly with MHC class II protein complex protein-containing complex organization regulation of biological process response to stimulus immune response biological regulation positive regulation of biological process positive regulation of response to stimulus positive regulation of immune response regulation of response to stimulus immune system process regulation of immune response regulation of immune system process positive regulation of immune system process peptide antigen assembly with MHC class II protein complex protein-containing complex organization peptide antigen assembly with MHC protein complex MHC class II protein complex assembly cellular component organization cellular component biogenesis antigen processing and presentation antigen processing and presentation of peptide or polysaccharide antigen via MHC class II cellular component assembly protein-containing complex assembly antigen processing and presentation of peptide antigen via MHC class II cellular process MHC protein complex assembly cellular component organization or biogenesis antigen processing and presentation of peptide antigen adaptive immune response antigen processing and presentation of exogenous peptide antigen via MHC class II antigen processing and presentation of exogenous peptide antigen antigen processing and presentation of exogenous antigen multicellular organismal process regulation of cellular process regulation of leukocyte activation regulation of cell activation positive regulation of leukocyte cell-cell adhesion lymphocyte activation leukocyte cell-cell adhesion leukocyte activation positive regulation of cell-cell adhesion positive regulation of lymphocyte activation positive regulation of cell activation cell adhesion cell-cell adhesion T cell activation positive regulation of leukocyte activation regulation of multicellular organismal process regulation of cell-cell adhesion positive regulation of cellular process positive regulation of T cell activation positive regulation of cell adhesion regulation of cell adhesion cell activation regulation of T cell activation regulation of leukocyte cell-cell adhesion positive regulation of multicellular organismal process regulation of lymphocyte activation	vacuolar membrane membrane-bounded organelle intracellular anatomical structure membrane lytic vacuole vacuole cellular anatomical entity intracellular membrane-bounded organelle intracellular organelle lytic vacuole membrane bounding membrane of organelle organelle lysosomal membrane cytoplasm vacuolar membrane membrane-bounded organelle intracellular anatomical structure membrane lytic vacuole vacuole cellular anatomical entity intracellular membrane-bounded organelle intracellular organelle lytic vacuole membrane bounding membrane of organelle organelle lysosomal membrane cytoplasm organelle membrane lysosome MHC protein complex cell periphery MHC class II protein complex protein-containing complex plasma membrane protein complex plasma membrane membrane protein complex endosome membrane endosome intracellular vesicle late endosome membrane endomembrane system cytoplasmic vesicle membrane cytoplasmic vesicle vesicle membrane late endosome vesicle
B	MHC CLASS II H2-IA-BETA CHAIN	binding antigen binding peptide antigen binding peptide binding protein-containing complex binding MHC protein complex binding MHC class II protein complex binding molecular transducer activity transmembrane signaling receptor activity signaling receptor activity MHC class II receptor activity immune receptor activity protein binding signaling receptor binding binding antigen binding peptide antigen binding peptide binding protein-containing complex binding MHC protein complex binding MHC class II protein complex binding molecular transducer activity transmembrane signaling receptor activity signaling receptor activity MHC class II receptor activity immune receptor activity protein binding signaling receptor binding CD4 receptor binding polysaccharide binding carbohydrate binding T cell receptor binding	regulation of biological process response to stimulus immune response biological regulation positive regulation of biological process positive regulation of response to stimulus positive regulation of immune response regulation of response to stimulus immune system process regulation of immune response regulation of immune system process positive regulation of immune system process adaptive immune response antigen processing and presentation of exogenous peptide antigen via MHC class II regulation of biological process response to stimulus immune response biological regulation positive regulation of biological process positive regulation of response to stimulus positive regulation of immune response regulation of response to stimulus immune system process regulation of immune response regulation of immune system process positive regulation of immune system process adaptive immune response antigen processing and presentation of exogenous peptide antigen via MHC class II antigen processing and presentation antigen processing and presentation of peptide or polysaccharide antigen via MHC class II antigen processing and presentation of peptide antigen via MHC class II antigen processing and presentation of exogenous peptide antigen antigen processing and presentation of peptide antigen antigen processing and presentation of exogenous antigen peptide antigen assembly with MHC class II protein complex protein-containing complex organization peptide antigen assembly with MHC protein complex MHC class II protein complex assembly cellular component organization cellular component biogenesis cellular component assembly protein-containing complex assembly cellular process MHC protein complex assembly cellular component organization or biogenesis multicellular organismal process regulation of cellular process regulation of leukocyte activation regulation of cell activation positive regulation of leukocyte cell-cell adhesion lymphocyte activation leukocyte cell-cell adhesion leukocyte activation positive regulation of cell-cell adhesion positive regulation of lymphocyte activation positive regulation of cell activation cell adhesion cell-cell adhesion T cell activation positive regulation of leukocyte activation regulation of multicellular organismal process regulation of cell-cell adhesion positive regulation of cellular process positive regulation of T cell activation positive regulation of cell adhesion regulation of cell adhesion cell activation regulation of T cell activation regulation of leukocyte cell-cell adhesion positive regulation of multicellular organismal process regulation of lymphocyte activation	cell periphery cell surface membrane plasma membrane cellular anatomical entity external side of plasma membrane side of membrane MHC protein complex MHC class II protein complex protein-containing complex plasma membrane protein complex membrane protein complex membrane-bounded organelle endosome membrane cell periphery cell surface membrane plasma membrane cellular anatomical entity external side of plasma membrane side of membrane MHC protein complex MHC class II protein complex protein-containing complex plasma membrane protein complex membrane protein complex membrane-bounded organelle endosome membrane intracellular anatomical structure endosome intracellular vesicle late endosome membrane intracellular membrane-bounded organelle endomembrane system intracellular organelle cytoplasmic vesicle membrane bounding membrane of organelle cytoplasmic vesicle vesicle membrane organelle late endosome cytoplasm vesicle organelle membrane immunological synapse vacuolar membrane lytic vacuole vacuole lytic vacuole membrane lysosomal membrane lysosome
C	TCR 226 alpha chain	-	-	-
D	TCR 226 beta chain	-	-	-
E	MCC peptide	binding organic cyclic compound binding tetrapyrrole binding heme binding electron transfer activity cation binding ion binding metal ion binding small molecule binding	-	membrane respirasome cellular anatomical entity membrane-bounded organelle intracellular anatomical structure mitochondrial intermembrane space mitochondrion membrane-enclosed lumen intracellular membrane-bounded organelle intracellular organelle lumen organelle envelope lumen intracellular organelle organelle envelope organelle lumen membrane respirasome cellular anatomical entity membrane-bounded organelle intracellular anatomical structure mitochondrial intermembrane space mitochondrion membrane-enclosed lumen intracellular membrane-bounded organelle intracellular organelle lumen organelle envelope lumen intracellular organelle organelle envelope organelle lumen organelle mitochondrial envelope cytoplasm

InterPro: Protein Family Classification InterPro Database Homepage

Chains	Accession	Name	Type
A	IPR036179	Immunoglobulin-like domain superfamily	Homologous Superfamily
A	IPR014745	MHC class II, alpha/beta chain, N-terminal	Homologous Superfamily
A	IPR003597	Immunoglobulin C1-set	Domain
A	IPR013783	Immunoglobulin-like fold	Homologous Superfamily
A	IPR011162	MHC classes I/II-like antigen recognition protein	Homologous Superfamily
A	IPR007110	Immunoglobulin-like domain	Domain
A	IPR001003	MHC class II, alpha chain, N-terminal	Domain
A	IPR003006	Immunoglobulin/major histocompatibility complex, conserved site	Conserved Site
B	IPR036179	Immunoglobulin-like domain superfamily	Homologous Superfamily
B	IPR003597	Immunoglobulin C1-set	Domain
B	IPR011162	MHC classes I/II-like antigen recognition protein	Homologous Superfamily
B	IPR003006	Immunoglobulin/major histocompatibility complex, conserved site	Conserved Site
B	IPR000353	MHC class II, beta chain, N-terminal	Domain
B	IPR014745	MHC class II, alpha/beta chain, N-terminal	Homologous Superfamily
B	IPR013783	Immunoglobulin-like fold	Homologous Superfamily
B	IPR007110	Immunoglobulin-like domain	Domain
E	IPR036909	Cytochrome c-like domain superfamily	Homologous Superfamily
E	IPR009056	Cytochrome c-like domain	Domain
E	IPR002327	Cytochrome c, class IA/ IB	Family

RCSB PDB Core Operations are funded by the National Science Foundation (DBI-1832184), 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 R01GM133198.