1kt2

CRYSTAL STRUCTURE OF CLASS II MHC MOLECULE IEK BOUND TO MOTH CYTOCHROME C PEPTIDE

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-D alpha chain

Mus musculus

UniProt P01904

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Other combination	Heteromer	Protein 2 其他Polymer 1	Fusion protein consisting of cytochrome C peptide, glycine rich linker, and MHC E-beta-k × 1 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose × 1 2-acetamido-2-deoxy-beta-D-glucopyranose × 2 water × 2	Consistent with protein count
2	Protein heterocomplex	Heteromer	Protein 2	Fusion protein consisting of cytochrome C peptide, glycine rich linker, and MHC E-beta-k × 1 2-acetamido-2-deoxy-beta-D-glucopyranose × 2 water × 2	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 1–182； UniProt 26–207 Author chain C； PDBConstruct 1–182； UniProt 26–207

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	1kt2
Deposition date deposition_date	2002-01-15
Structure title title	CRYSTAL STRUCTURE OF CLASS II MHC MOLECULE IEK BOUND TO MOTH CYTOCHROME C PEPTIDE
Keywords keywords	Protein-peptide complex, T cell receptor, antigen presentation, cytochrome, 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.

1kt2__assembly_1__model_1

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

Download this curve (.dat)

1kt2__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

1kt2__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	24.80 Å
Rg (electron density)	23.74 Å
Total Rg	24.65 Å
Atom count	3278
Residues	395
Excluded volume	57818 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`1kt2__assembly_1__model_1`	dimeric （2）	Success	4.1.3-1-20251215 (887e7ef)	View Download
2	1	`1kt2__assembly_2__model_1`	dimeric （2）	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	H-2 class II histocompatibility antigen, E-D alpha chain
Molecular weight formula_weight	21204.7 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	6743

IKEEHTIIQAEFYLLPDKRGEFMFDFDGDEIFHVDIEKSETIWRLEEFAKFASFEAQGALANIAVDKANLDVMKERSNNTPDANVAPEVTVLSRSPVNLGEPNILICFIDKFSPPVVNVTWLRNGRPVTEGVSETVFLPRDDHLFRKFHYLTFLPSTDDFYDCEVDHWGLEEPLRKHWEFEE

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	Fusion protein consisting of cytochrome C peptide, glycine rich linker, and MHC E-beta-k
Molecular weight formula_weight	24399.2 kDa
Source method src_method	man
Copy count entity_count	2

Polymer Polymer

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

ADLIAYLKQATKGGGGSLVPRGSGGGGSRPWFLEYCKSECHFYNGTQRVRLLVRYFYNLEENLRFDSDVGEFRAVTELGRPDAENWNSQPEFLEQKRAEVDTVCRHNYEIFDNFLVPRRVEPTVTVYPTKTQPLEHHNLLVCSVSDFYPGNIEVRWFRNGKEEKTGIVSTGLVRNGDWTFQTLVMLETVPQSGEVYTCQVEHPSLTDPVTVEW

Source Source

Source organism organism	Lonomia obliqua, Mus musculus
Common name common_name	, house mouse
Host organism host_organism	Spodoptera frugiperda

Entity 3 Entity 3 branched

Description description	2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose
Molecular weight formula_weight	424.4 kDa
Source method src_method	man
Copy count entity_count	1

Entity 4 Entity 4 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	4

Entity 5 Entity 5 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	215

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6. Fold Classification (SCOP + CATH) 16 domains

SCOP 2.08 (8 domains)

Domain ID domain_id	d1kt2a1
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	d1kt2a2
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	d1kt2b1
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	d1kt2b2
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	d1kt2c1
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	d1kt2c2
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	d1kt2d1
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	d1kt2d2
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	1kt2A01
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	1kt2A02
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	1kt2B01
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	1kt2B02
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	1kt2C01
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	1kt2C02
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	1kt2D01
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	1kt2D02
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	147.790 Å
Unit-cell length b length_b	56.930 Å
Unit-cell length c length_c	115.990 Å
Unit-cell angle α angle_alpha	90.00 °
Unit-cell angle β angle_beta	92.12 °
Unit-cell angle γ angle_gamma	90.00 °
Molecules per unit cell Z z_pdb	8

Space group space_group	C 1 2 1
Space-group number int_tables_number	5
Crystal system crystal_system	—

Resolution resolution	2.800 Å
Low-resolution limit resolution_low	19.930 Å
R factor r_factor	—
R_work r_work	0.2200
R_free r_free	0.2940

CRYSTAL STRUCTURE OF CLASS II MHC MOLECULE IEK BOUND TO MOTH CYTOCHROME C PEPTIDE

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

H-2 class II histocompatibility antigen, E-D alpha 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

1kt2__assembly_1__model_1

1kt2__assembly_1__model_1 | I(q)

1kt2__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 branched

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)

CRYSTAL STRUCTURE OF CLASS II MHC MOLECULE IEK BOUND TO MOTH CYTOCHROME C PEPTIDE

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

H-2 class II histocompatibility antigen, E-D 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

2. Structure Basics 2. Structure Basics

3. Official assembly/model SAXS Official SAXS Profiles

1kt2__assembly_1__model_1

1kt2__assembly_1__model_1 | I(q)

1kt2__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 branched

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)