3c6l

Crystal structure of mouse MHC class II I-Ab/3K peptide complexed with mouse TCR 2W20

Method: X-RAY DIFFRACTION

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1. Protein Identity and Related Structures Protein Identity & Related Structures

H-2 class II histocompatibility antigen, A-B alpha chain

Mus musculus

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein heterocomplex	Heteromer	Protein 8	TCR 2W20 alpha chain × 2 TCR 2W20 beta chain × 2 3K peptide, Linker,and H-2 class II histocompatibility antigen (A beta chain) × 2 （P14483） CALCIUM ION × 3	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	HA2B_MOUSE
Isoform	—
PDB entities	3
Chains and sequence ranges	Author chain C； PDBConstruct 1–182； UniProt 27–208 Author chain G； PDBConstruct 1–182； UniProt 27–208

3K peptide, Linker,and H-2 class II histocompatibility antigen (A beta chain)

Mus musculus

UniProt P14483

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein heterocomplex	Heteromer	Protein 8	TCR 2W20 alpha chain × 2 TCR 2W20 beta chain × 2 H-2 class II histocompatibility antigen, A-B alpha chain × 2 （P14434） CALCIUM ION × 3	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	HB2A_MOUSE
Isoform	—
PDB entities	4
Chains and sequence ranges	Author chain D； PDBConstruct 29–217； UniProt 30–218 Author chain H； PDBConstruct 29–217； UniProt 30–218

The page prioritizes protein identity, the current assembly, associated components, oligomeric state and cross-PDB links. Chain mapping and sequence ranges are retained as data evidence. Internal IDs, import timestamps and assembly operation expressions are maintenance fields and are not shown here.

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2. Structure Basics 2. Structure Basics

Entry ID entry_id	3c6l
Deposition date deposition_date	2008-02-04
Structure title title	Crystal structure of mouse MHC class II I-Ab/3K peptide complexed with mouse TCR 2W20
Keywords keywords	TCR-pMHC complex, Glycoprotein, Immune response, Membrane, MHC II, Transmembrane, SUGAR BINDING PROTEIN-IMMUNE SYSTEM COMPLEX; SUGAR BINDING PROTEIN/IMMUNE SYSTEM
Experimental Method method	X-RAY DIFFRACTION

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3. Official assembly/model SAXS Official SAXS Profiles

This page reads only the latest assembly calculations. Every curve maps to an explicit PDB entry, official biological assembly and coordinate model.

3c6l__assembly_1__model_1

Assembly 1 · Model 1 · CRYSOL 4.1.3-1-20251215 (887e7ef)

Download this curve (.dat)

3c6l__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

3c6l__assembly_1__model_1 | P(r) · Pending

P(r) will be calculated and displayed separately for the same assembly/model.

Rg（Guinier）	59.36 Å
Rg (electron density)	60.83 Å
Total Rg	60.61 Å
Atom count	12716
Residues	1580
Excluded volume	223880 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`3c6l__assembly_1__model_1`	octameric （8）	Success	4.1.3-1-20251215 (887e7ef)	View Download

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4. Crystallography and Experiment 4. Crystallography & Experiment

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5. Entities and Polymers Entities & Polymers (5)

Entity 1 Entity 1 polymer

Description description	TCR 2W20 alpha chain
Molecular weight formula_weight	20957.3 kDa
Source method src_method	man
Copy count entity_count	2

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	A,E
Atom count atom_count	12716

QQVRQSPQSLTVWEGETAILNCSYEDSTFDYFPWYHQFPGESPALLIAIRPVSNKKEDGRFTIFFNKREKKFSLHIADSQPGDSATYFCAASDNRIFFGDGTQLVVKPNIQNPEPAVYQLKDPRSQDSTLCLFTDFDSQINVPKTMESGTFITDKTVLDMKAMDSKSNGAIAWSNQTSFTCQDIF

Source Source

Source organism organism	Mus musculus
Common name common_name	house mouse
NCBI taxonomy ID ncbi_taxonomy_id	10090
Host organism host_organism	Spodoptera frugiperda

Entity 2 Entity 2 polymer

Description description	TCR 2W20 beta chain
Molecular weight formula_weight	26487.3 kDa
Source method src_method	man
Copy count entity_count	2

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	B,F

AVTQSPRNKVAVTGGKVTLSCNQTNNHNNMYWYRQDTGHGLRLIHYSYGAGSTEKGDIPDGYKASRPSQENFSLILELATPSQTSVYFCASGDAWGYEQYFGPGTRLTVLEDLRDVTPPKVSLFEPSKAEIANKQKATLVCLARGFFPDHVELSWWVNGKEVHSGVSTDPQAYKESNYSYCLSSRLRVSATFWHNPRNHFRCQVQFHGLSEEDKWPEGSPKPVTQDISAEAWGRAD

Source Source

Source organism organism	Mus musculus
Common name common_name	house mouse
NCBI taxonomy ID ncbi_taxonomy_id	10090
Host organism host_organism	Spodoptera frugiperda

Entity 3 Entity 3 polymer

Description description	H-2 class II histocompatibility antigen, A-B alpha chain
Molecular weight formula_weight	20598.0 kDa
Source method src_method	man
Copy count entity_count	2

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	C,G

IEADHVGTYGISVYQSPGDIGQYTFEFDGDELFYVDLDKKETVWMLPEFGQLASFDPQGGLQNIAVVKHNLGVLTKRSNSTPATNEAPQATVFPKSPVLLGQPNTLICFVDNIFPPVINITWLRNSKSVADGVYETSFFVNRDYSFHKLSYLTFIPSDDDIYDCKVEHWGLEEPVLKHWEPE

Source Source

Source organism organism	Mus musculus
Common name common_name	house mouse
NCBI taxonomy ID ncbi_taxonomy_id	10090
Host organism host_organism	Spodoptera frugiperda

Entity 4 Entity 4 polymer

Description description	3K peptide, Linker,and H-2 class II histocompatibility antigen (A beta chain)
Molecular weight formula_weight	24938.8 kDa
Source method src_method	man
Copy count entity_count	2

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	D,H

FEAQKAKANKAVDGGGGSLVPRGSGGGGSERHFVYQFMGECYFTNGTQRIRYVTRYIYNREEYVRYDSDVGEHRAVTELGRPDAEYWNSQPEILERTRAELDTVCRHNYEGPETHTSLRRLEQPNVVISLSRTEALNHHNTLVCSVTDFYPAKIKVRWFRNGQEETVGVSSTQLIRNGDWTFQVLVMLEMTPRRGEVYTCHVEHPSLKSPITVEWKA

Source Source

Source organism organism	Mus musculus
Common name common_name	house mouse
NCBI taxonomy ID ncbi_taxonomy_id	10090
Host organism host_organism	Spodoptera frugiperda

Entity 5 Entity 5 non-polymer

Description description	CALCIUM ION
Molecular weight formula_weight	40.1 kDa
Source method src_method	syn
Copy count entity_count	3

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6. Fold Classification (SCOP + CATH) 28 domains

SCOP 2.08 (12 domains)

Domain ID domain_id	d3c6la1
Class class	b — All beta proteins
Fold Fold fold	b.1 — Immunoglobulin-like beta-sandwich
Superfamily Superfamily superfamily	b.1.1 — Immunoglobulin
Family Family family	b.1.1.1 — V set domains (antibody variable domain-like)

Domain ID domain_id	d3c6la2
Class class	b — All beta proteins
Fold Fold fold	b.1 — Immunoglobulin-like beta-sandwich
Superfamily Superfamily superfamily	b.1.1 — Immunoglobulin
Family Family family	b.1.1.2 — C1 set domains (antibody constant domain-like)

Domain ID domain_id	d3c6lc1
Class class	b — All beta proteins
Fold Fold fold	b.1 — Immunoglobulin-like beta-sandwich
Superfamily Superfamily superfamily	b.1.1 — Immunoglobulin
Family Family family	b.1.1.2 — C1 set domains (antibody constant domain-like)

Domain ID domain_id	d3c6lc2
Class class	d — Alpha and beta proteins (a+b)
Fold Fold fold	d.19 — MHC antigen-recognition domain
Superfamily Superfamily superfamily	d.19.1 — MHC antigen-recognition domain
Family Family family	d.19.1.1 — MHC antigen-recognition domain

Domain ID domain_id	d3c6ld1
Class class	b — All beta proteins
Fold Fold fold	b.1 — Immunoglobulin-like beta-sandwich
Superfamily Superfamily superfamily	b.1.1 — Immunoglobulin
Family Family family	b.1.1.2 — C1 set domains (antibody constant domain-like)

Domain ID domain_id	d3c6ld2
Class class	d — Alpha and beta proteins (a+b)
Fold Fold fold	d.19 — MHC antigen-recognition domain
Superfamily Superfamily superfamily	d.19.1 — MHC antigen-recognition domain
Family Family family	d.19.1.1 — MHC antigen-recognition domain

Domain ID domain_id	d3c6le1
Class class	b — All beta proteins
Fold Fold fold	b.1 — Immunoglobulin-like beta-sandwich
Superfamily Superfamily superfamily	b.1.1 — Immunoglobulin
Family Family family	b.1.1.1 — V set domains (antibody variable domain-like)

Domain ID domain_id	d3c6le2
Class class	b — All beta proteins
Fold Fold fold	b.1 — Immunoglobulin-like beta-sandwich
Superfamily Superfamily superfamily	b.1.1 — Immunoglobulin
Family Family family	b.1.1.2 — C1 set domains (antibody constant domain-like)

Domain ID domain_id	d3c6lg1
Class class	b — All beta proteins
Fold Fold fold	b.1 — Immunoglobulin-like beta-sandwich
Superfamily Superfamily superfamily	b.1.1 — Immunoglobulin
Family Family family	b.1.1.2 — C1 set domains (antibody constant domain-like)

Domain ID domain_id	d3c6lg2
Class class	d — Alpha and beta proteins (a+b)
Fold Fold fold	d.19 — MHC antigen-recognition domain
Superfamily Superfamily superfamily	d.19.1 — MHC antigen-recognition domain
Family Family family	d.19.1.1 — MHC antigen-recognition domain

Domain ID domain_id	d3c6lh1
Class class	b — All beta proteins
Fold Fold fold	b.1 — Immunoglobulin-like beta-sandwich
Superfamily Superfamily superfamily	b.1.1 — Immunoglobulin
Family Family family	b.1.1.2 — C1 set domains (antibody constant domain-like)

Domain ID domain_id	d3c6lh2
Class class	d — Alpha and beta proteins (a+b)
Fold Fold fold	d.19 — MHC antigen-recognition domain
Superfamily Superfamily superfamily	d.19.1 — MHC antigen-recognition domain
Family Family family	d.19.1.1 — MHC antigen-recognition domain

CATH v4.4 (16 domains)

Domain ID domain_id	3c6lA01
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	3c6lA02
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	3c6lB01
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	3c6lB02
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	3c6lC01
Class class	3 — Alpha Beta
Architecture architecture	10 — Roll
Topology topology	320 — Class II Histocompatibility Antigen, M Beta Chain; Chain B, domain 1
Homologous superfamily homologous superfamily	10 — Class II Histocompatibility Antigen, M Beta Chain; Chain B, domain 1

Domain ID domain_id	3c6lC02
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	3c6lD01
Class class	3 — Alpha Beta
Architecture architecture	10 — Roll
Topology topology	320 — Class II Histocompatibility Antigen, M Beta Chain; Chain B, domain 1
Homologous superfamily homologous superfamily	10 — Class II Histocompatibility Antigen, M Beta Chain; Chain B, domain 1

Domain ID domain_id	3c6lD02
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	3c6lE01
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	3c6lE02
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	3c6lF01
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	3c6lF02
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	3c6lG01
Class class	3 — Alpha Beta
Architecture architecture	10 — Roll
Topology topology	320 — Class II Histocompatibility Antigen, M Beta Chain; Chain B, domain 1
Homologous superfamily homologous superfamily	10 — Class II Histocompatibility Antigen, M Beta Chain; Chain B, domain 1

Domain ID domain_id	3c6lG02
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	3c6lH01
Class class	3 — Alpha Beta
Architecture architecture	10 — Roll
Topology topology	320 — Class II Histocompatibility Antigen, M Beta Chain; Chain B, domain 1
Homologous superfamily homologous superfamily	10 — Class II Histocompatibility Antigen, M Beta Chain; Chain B, domain 1

Domain ID domain_id	3c6lH02
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

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Unit-cell length a length_a	46.540 Å
Unit-cell length b length_b	113.930 Å
Unit-cell length c length_c	386.260 Å
Unit-cell angle α angle_alpha	90.00 °
Unit-cell angle β angle_beta	90.00 °
Unit-cell angle γ angle_gamma	90.00 °
Molecules per unit cell Z z_pdb	8

Space group space_group	P 21 21 21
Space-group number int_tables_number	19
Crystal system crystal_system	—

Resolution resolution	3.400 Å
Low-resolution limit resolution_low	49.070 Å
R factor r_factor	—
R_work r_work	0.2680
R_free r_free	0.3250

Crystal structure of mouse MHC class II I-Ab/3K peptide complexed with mouse TCR 2W20

1. Protein Identity and Related Structures Protein Identity & Related Structures

H-2 class II histocompatibility antigen, A-B alpha chain

State in the Current Structure

Other States of the Same Protein in the Database

3K peptide, Linker,and H-2 class II histocompatibility antigen (A beta chain)

State in the Current Structure

Other States of the Same Protein in the Database

2. Structure Basics 2. Structure Basics

3. Official assembly/model SAXS Official SAXS Profiles

3c6l__assembly_1__model_1

3c6l__assembly_1__model_1 | I(q)

3c6l__assembly_1__model_1 | P(r) · Pending

4. Crystallography and Experiment 4. Crystallography & Experiment

Unit cell Unit Cell

Symmetry Symmetry

Refinement Refinement

Diffraction experiment Diffraction

5. Entities and Polymers Entities & Polymers (5)

Entity 1 Entity 1 polymer

Polymer Polymer

Source Source

Entity 2 Entity 2 polymer

Polymer Polymer

Source Source

Entity 3 Entity 3 polymer

Polymer Polymer

Source Source

Entity 4 Entity 4 polymer

Polymer Polymer

Source Source

Entity 5 Entity 5 non-polymer

6. Fold Classification (SCOP + CATH) 28 domains

SCOP 2.08 (12 domains)

CATH v4.4 (16 domains)

7. Citations (1)

Crystal structure of mouse MHC class II I-Ab/3K peptide complexed with mouse TCR 2W20

1. Protein Identity and Related Structures Protein Identity & Related Structures

H-2 class II histocompatibility antigen, A-B alpha chain

State in the Current Structure

Other States of the Same Protein in the Database

Monomer

Homodimer

Homotetramer

Other homooligomers

Heteromeric or nucleic-acid complex

3K peptide, Linker,and H-2 class II histocompatibility antigen (A beta chain)

State in the Current Structure

Other States of the Same Protein in the Database

Monomer

Homodimer

Homotetramer

Other homooligomers

Heteromeric or nucleic-acid complex

2. Structure Basics 2. Structure Basics

3. Official assembly/model SAXS Official SAXS Profiles

3c6l__assembly_1__model_1

3c6l__assembly_1__model_1 | I(q)

3c6l__assembly_1__model_1 | P(r) · Pending

4. Crystallography and Experiment 4. Crystallography & Experiment

Unit cell Unit Cell

Symmetry Symmetry

Refinement Refinement

Diffraction experiment Diffraction

5. Entities and Polymers Entities & Polymers (5)

Entity 1 Entity 1 polymer

Polymer Polymer

Source Source

Entity 2 Entity 2 polymer

Polymer Polymer

Source Source

Entity 3 Entity 3 polymer

Polymer Polymer

Source Source

Entity 4 Entity 4 polymer

Polymer Polymer

Source Source

Entity 5 Entity 5 non-polymer

6. Fold Classification (SCOP + CATH) 28 domains

SCOP 2.08 (12 domains)

CATH v4.4 (16 domains)

7. Citations (1)