3qib

Crystal structure of the 2B4 TCR in complex with MCC/I-Ek

Method: X-RAY DIFFRACTION

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

H-2 class II histocompatibility antigen, E-K 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 5	MHC class II E-beta-k × 1 （Q31163） T-cell receptor alpha chain C region × 1 2B4 beta chain × 1 MCC peptide × 1 （P00039） 2-acetamido-2-deoxy-beta-D-glucopyranose × 2 alpha-L-fucopyranose × 2 DI(HYDROXYETHYL)ETHER × 7 beta-D-mannopyranose × 1 water × 5	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	HA22_MOUSE
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 1–191； UniProt 26–216

MHC class II E-beta-k

Mus musculus

UniProt Q31163

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein heterocomplex	Heteromer	Protein 5	H-2 class II histocompatibility antigen, E-K alpha chain × 1 （P04224） T-cell receptor alpha chain C region × 1 2B4 beta chain × 1 MCC peptide × 1 （P00039） 2-acetamido-2-deoxy-beta-D-glucopyranose × 2 alpha-L-fucopyranose × 2 DI(HYDROXYETHYL)ETHER × 7 beta-D-mannopyranose × 1 water × 5	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	Q31163_MOUSE
Isoform	—
PDB entities	2
Chains and sequence ranges	Author chain B； PDBConstruct 7–202； UniProt 29–224

MCC peptide

Manduca sexta

UniProt P00039

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein heterocomplex	Heteromer	Protein 5	H-2 class II histocompatibility antigen, E-K alpha chain × 1 （P04224） MHC class II E-beta-k × 1 （Q31163） T-cell receptor alpha chain C region × 1 2B4 beta chain × 1 2-acetamido-2-deoxy-beta-D-glucopyranose × 2 alpha-L-fucopyranose × 2 DI(HYDROXYETHYL)ETHER × 7 beta-D-mannopyranose × 1 water × 5	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	CYC_MANSE
Isoform	—
PDB entities	5
Chains and sequence ranges	Author chain P； PDBConstruct 1–12； UniProt 97–108

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	3qib
Deposition date deposition_date	2011-01-26
Structure title title	Crystal structure of the 2B4 TCR in complex with MCC/I-Ek
Keywords keywords	Ig domain, IMMUNE SYSTEM; 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.

3qib__assembly_1__model_1

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

Download this curve (.dat)

3qib__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

3qib__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	35.56 Å
Rg (electron density)	35.78 Å
Total Rg	35.95 Å
Atom count	6359
Residues	794
Excluded volume	112180 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`3qib__assembly_1__model_1`	pentameric （5）	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 (10)

Entity 1 Entity 1 polymer

Description description	H-2 class II histocompatibility antigen, E-K alpha chain
Molecular weight formula_weight	22491.2 kDa
Source method src_method	man
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	A
Atom count atom_count	6465

IKEEHTIIQAEFYLLPDKRGEFMFDFDGDEIFHVDIEKSETIWRLEEFAKFASFEAQGALANIAVDKANLDVMKERSNNTPDANVAPEVTVLSRSPVNLGEPNILICFIDKFSPPVVNVTWLRNGRPVTEGVSETVFLPRDDHLFRKFHYLTFLPSTDDFYDCEVDHWGLEEPLRKHWEFEEKTLLPETKESR

Source Source

Source organism organism	Mus musculus
Common name common_name	mouse
NCBI taxonomy ID ncbi_taxonomy_id	10090
Host organism host_organism	Trichoplusia ni

Entity 2 Entity 2 polymer

Description description	MHC class II E-beta-k
Molecular weight formula_weight	23344.9 kDa
Source method src_method	man
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	B

GSGGGGSRPWFLEYCKSECHFYNGTQRVRLLVRYFYNLEENLRFDSDVGEFRAVTELGRPDAENWNSQPEFLEQKRAEVDTVCRHNYEIFDNFLVPRRVEPTVTVYPTKTQPLEHHNLLVCSVSDFYPGNIEVRWFRNGKEEKTGIVSTGLVRNGDWTFQTLVMLETVPQSGEVYTCQVEHPSLTDPVTVEWKAQSTSAQNK

Source Source

Source organism organism	Mus musculus
Common name common_name	mouse
NCBI taxonomy ID ncbi_taxonomy_id	10090
Host organism host_organism	Trichoplusia ni

Entity 3 Entity 3 polymer

Description description	T-cell receptor alpha chain C region
Molecular weight formula_weight	22807.1 kDa
Source method src_method	man
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	C

MRGDQVEQSPSALSLHEGTGSALRCNFTTTMRAVQWFQQNSRGSLINLFYLASGTKENGRLKSTFNSKESYSTLHIRDAQLEDSGTYFCAALRATGGNNKLTFGQGTVLSVIPDIQNPDPAVYQLRDSKSSDKSVCLFTDFDSQTNVSQSKDSDVYITDKCVLDMRSMDFKSNSAVAWSNKSDFACANAFNNSIIPEDTFFPSPESS

Source Source

Source organism organism	Homo sapiens
Common name common_name	human
NCBI taxonomy ID ncbi_taxonomy_id	9606
Host organism host_organism	Escherichia coli

Entity 4 Entity 4 polymer

Description description	2B4 beta chain
Molecular weight formula_weight	30288.9 kDa
Source method src_method	man
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	D

MANERADLIAYLKQATKGGGGSGGGGGMKVIQTPRYLVKGQGQKAKMRCIPEKGHPVVFWYQQNKNNEFKFLINFQNQEVLQQIDMTEKRFSAECPSNSPCSLEIQSSEAGDSALYLCASSLNWSQDTQYFGPGTRLLVLEDLKNVFPPEVAVFEPSEAEISHTQKATLVCLATGFYPDHVELSWWVNGKEVHSGVCTDPQPLKEQPALNDSRYALSSRLRVSATFWQNPRNHFRCQVQFYGLSENDEWTQDRAKPVTQIVSAEAWGRAD

Source Source

Source organism organism	Mus musculus
NCBI taxonomy ID ncbi_taxonomy_id	10090
Host organism host_organism	Escherichia coli

Entity 5 Entity 5 polymer

Description description	MCC peptide
Molecular weight formula_weight	1393.6 kDa
Source method src_method	man
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	P

ADLIAYLKQATKG

Source Source

Source organism organism	Manduca sexta
NCBI taxonomy ID ncbi_taxonomy_id	7130
Host organism host_organism	Escherichia coli

Entity 6 Entity 6 non-polymer

Description description	2-acetamido-2-deoxy-beta-D-glucopyranose
Molecular weight formula_weight	221.2 kDa
Source method src_method	man
Copy count entity_count	2

Entity 7 Entity 7 non-polymer

Description description	alpha-L-fucopyranose
Molecular weight formula_weight	164.2 kDa
Source method src_method	man
Copy count entity_count	2

Entity 8 Entity 8 non-polymer

Description description	DI(HYDROXYETHYL)ETHER
Molecular weight formula_weight	106.1 kDa
Source method src_method	syn
Copy count entity_count	7

Entity 9 Entity 9 non-polymer

Description description	beta-D-mannopyranose
Molecular weight formula_weight	180.2 kDa
Source method src_method	man
Copy count entity_count	1

Entity 10 Entity 10 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	106

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6. Fold Classification (SCOP + CATH) 16 domains

SCOP 2.08 (8 domains)

Domain ID domain_id	d3qiba1
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.19.1.0 — automated matches

Domain ID domain_id	d3qiba2
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	d3qibb1
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	d3qibb2
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	d3qibc1
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.1.1.0 — automated matches

Domain ID domain_id	d3qibc2
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	d3qibd1
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.1.1.0 — automated matches

Domain ID domain_id	d3qibd2
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)

CATH v4.4 (8 domains)

Domain ID domain_id	3qibA01
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	3qibA02
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	3qibB01
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	3qibB02
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	3qibC01
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	3qibC02
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	3qibD01
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	3qibD02
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	146.749 Å
Unit-cell length b length_b	167.178 Å
Unit-cell length c length_c	259.489 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	16

Space group space_group	F 2 2 2
Space-group number int_tables_number	22
Crystal system crystal_system	—

Resolution resolution	2.700 Å
Low-resolution limit resolution_low	34.970 Å
R factor r_factor	0.2220
R_work r_work	0.2210
R_free r_free	0.2460

Crystal structure of the 2B4 TCR in complex with MCC/I-Ek

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

H-2 class II histocompatibility antigen, E-K 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

MHC class II E-beta-k

State in the Current Structure

Other States of the Same Protein in the Database

Monomer

Homodimer

Homotetramer

Other homooligomers

Heteromeric or nucleic-acid complex

MCC peptide

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

3qib__assembly_1__model_1

3qib__assembly_1__model_1 | I(q)

3qib__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 (10)

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 polymer

Polymer Polymer

Source Source

Entity 6 Entity 6 non-polymer

Entity 7 Entity 7 non-polymer

Entity 8 Entity 8 non-polymer

Entity 9 Entity 9 non-polymer

Entity 10 Entity 10 water

6. Fold Classification (SCOP + CATH) 16 domains

SCOP 2.08 (8 domains)

CATH v4.4 (8 domains)

7. Citations (1)