1ieb

HISTOCOMPATIBILITY ANTIGEN

Method: X-RAY DIFFRACTION

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

MHC CLASS II I-EK

Mus musculus

UniProt P01904

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein heterocomplex	Heteromer	Protein 2	MHC CLASS II I-EK × 1 （Q31164） 2-acetamido-2-deoxy-beta-D-glucopyranose × 3 water × 2	Consistent with protein count
2	Protein heterocomplex	Heteromer	Protein 2	MHC CLASS II I-EK × 1 （Q31164） 2-acetamido-2-deoxy-beta-D-glucopyranose × 3 SULFATE ION × 1 water × 2	Consistent with protein count
3	Protein heterocomplex	Heteromer	Protein 4	MHC CLASS II I-EK × 2 （Q31164） 2-acetamido-2-deoxy-beta-D-glucopyranose × 6 SULFATE ION × 1 water × 4	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	HA21_MOUSE
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 1–192； UniProt 26–217 Author chain C； PDBConstruct 1–192； UniProt 26–217

MHC CLASS II I-EK

Mus musculus

UniProt Q31164

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein heterocomplex	Heteromer	Protein 2	MHC CLASS II I-EK × 1 （P01904） 2-acetamido-2-deoxy-beta-D-glucopyranose × 3 water × 2	Consistent with protein count
2	Protein heterocomplex	Heteromer	Protein 2	MHC CLASS II I-EK × 1 （P01904） 2-acetamido-2-deoxy-beta-D-glucopyranose × 3 SULFATE ION × 1 water × 2	Consistent with protein count
3	Protein heterocomplex	Heteromer	Protein 4	MHC CLASS II I-EK × 2 （P01904） 2-acetamido-2-deoxy-beta-D-glucopyranose × 6 SULFATE ION × 1 water × 4	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	Q31164_MOUSE
Isoform	—
PDB entities	2
Chains and sequence ranges	Author chain B； PDBConstruct 1–227； UniProt 1–198 Author chain D； PDBConstruct 1–227； UniProt 1–198

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	1ieb
Deposition date deposition_date	1996-04-05
Structure title title	HISTOCOMPATIBILITY ANTIGEN
Keywords keywords	HISTOCOMPATIBILITY ANTIGEN; HISTOCOMPATIBILITY ANTIGEN
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.

1ieb__assembly_1__model_1

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

Download this curve (.dat)

1ieb__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

1ieb__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	24.53 Å
Rg (electron density)	23.57 Å
Total Rg	24.46 Å
Atom count	3254
Residues	396
Excluded volume	57407 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`1ieb__assembly_1__model_1`	dimeric （2）	Success	4.1.3-1-20251215 (887e7ef)	View Download
2	1	`1ieb__assembly_2__model_1`	dimeric （2）	Success	4.1.3-1-20251215 (887e7ef)	View Download
3	1	`1ieb__assembly_3__model_1`	tetrameric （4）	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	MHC CLASS II I-EK
Molecular weight formula_weight	22324.0 kDa
Source method src_method	man
Copy count entity_count	2

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	A,C
Atom count atom_count	6672

IKEEHTIIQAEFYLLPDKRGEFMFDFDGDEIFHVDIEKSETIWRLEEFAKFASFEAQGALANIAVDKANLDVMKERSNNTPDANVAPEVTVLSRSPVNLGEPNILICFIDKFSPPVVNVTWLRNGRPVTEGVSETVFLPRDDHLFRKFHYLTFLPSTDDFYDCEVDHWGLEEPLRKTWEFEEKTLLPETKEN

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	MHC CLASS II I-EK
Molecular weight formula_weight	26307.4 kDa
Source method src_method	man
Copy count entity_count	2

Polymer Polymer

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

RDSRDRMVNHFIAEFKRKGGSLVPRGSGGGGSRPWFLEYCKSECHFYNGTQRVRLLVRYFYNLEENLRFDSDVGEFRAVTELGRPDAENWNSQPEFLEQKRAEVDTVCRHNYEIFDNFLVPRRVEPTVTVYPTKTQPLEHHNLLVCSVSDFYPGNIEVRWFRNGKEEKTGIVSTGLVRNGDWTFQTLVMLETVPQSGEVYTCQVEHPSLTDPVTVEWKAQSTSAQNK

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 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	6

Entity 4 Entity 4 non-polymer

Description description	SULFATE ION
Molecular weight formula_weight	96.1 kDa
Source method src_method	syn
Copy count entity_count	1

Entity 5 Entity 5 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	159

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6. Fold Classification (SCOP + CATH) 16 domains

SCOP 2.08 (8 domains)

Domain ID domain_id	d1ieba1
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	d1ieba2
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	d1iebb1
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	d1iebb2
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	d1iebc1
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	d1iebc2
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	d1iebd1
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	d1iebd2
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 (8 domains)

Domain ID domain_id	1iebA01
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	1iebA02
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	1iebB01
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	1iebB02
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	1iebC01
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	1iebC02
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	1iebD01
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	1iebD02
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	77.530 Å
Unit-cell length b length_b	77.530 Å
Unit-cell length c length_c	319.480 Å
Unit-cell angle α angle_alpha	90.00 °
Unit-cell angle β angle_beta	90.00 °
Unit-cell angle γ angle_gamma	120.00 °
Molecules per unit cell Z z_pdb	12

Space group space_group	P 31 2 1
Space-group number int_tables_number	152
Crystal system crystal_system	—

Resolution resolution	2.700 Å
Low-resolution limit resolution_low	6.000 Å
R factor r_factor	0.2220
R_work r_work	0.2220
R_free r_free	0.3210

HISTOCOMPATIBILITY ANTIGEN

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

MHC CLASS II I-EK

State in the Current Structure

Other States of the Same Protein in the Database

MHC CLASS II I-EK

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

1ieb__assembly_1__model_1

1ieb__assembly_1__model_1 | I(q)

1ieb__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 non-polymer

Entity 4 Entity 4 non-polymer

Entity 5 Entity 5 water

6. Fold Classification (SCOP + CATH) 16 domains

SCOP 2.08 (8 domains)

CATH v4.4 (8 domains)

7. Citations (1)

HISTOCOMPATIBILITY ANTIGEN

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

MHC CLASS II I-EK

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 I-EK

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

1ieb__assembly_1__model_1

1ieb__assembly_1__model_1 | I(q)

1ieb__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 non-polymer

Entity 4 Entity 4 non-polymer

Entity 5 Entity 5 water

6. Fold Classification (SCOP + CATH) 16 domains

SCOP 2.08 (8 domains)

CATH v4.4 (8 domains)

7. Citations (1)