1hsa

THE THREE-DIMENSIONAL STRUCTURE OF HLA-B27 AT 2.1 ANGSTROMS RESOLUTION SUGGESTS A GENERAL MECHANISM FOR TIGHT PEPTIDE BINDING TO MHC

Method: X-RAY DIFFRACTION

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

CLASS I HISTOCOMPATIBILITY ANTIGEN (HLA-B*2705)

Homo sapiens

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein heterocomplex	Heteromer	Protein 3	BETA 2-MICROGLOBULIN × 1 （P61769） MODEL PEPTIDE SEQUENCE - ARAAAAAAA × 1 water × 3	Consistent with protein count
2	Protein heterocomplex	Heteromer	Protein 3	BETA 2-MICROGLOBULIN × 1 （P61769） MODEL PEPTIDE SEQUENCE - ARAAAAAAA × 1 water × 3	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	1B27_HUMAN
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 1–276； UniProt 25–300 Author chain D； PDBConstruct 1–276； UniProt 25–300

BETA 2-MICROGLOBULIN

Homo sapiens

UniProt P61769

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein heterocomplex	Heteromer	Protein 3	CLASS I HISTOCOMPATIBILITY ANTIGEN (HLA-B*2705) × 1 （P03989） MODEL PEPTIDE SEQUENCE - ARAAAAAAA × 1 water × 3	Consistent with protein count
2	Protein heterocomplex	Heteromer	Protein 3	CLASS I HISTOCOMPATIBILITY ANTIGEN (HLA-B*2705) × 1 （P03989） MODEL PEPTIDE SEQUENCE - ARAAAAAAA × 1 water × 3	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	B2MG_HUMAN
Isoform	—
PDB entities	2
Chains and sequence ranges	Author chain B； PDBConstruct 1–99； UniProt 21–119 Author chain E； PDBConstruct 1–99； UniProt 21–119

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	1hsa
Deposition date deposition_date	1992-08-11
Structure title title	THE THREE-DIMENSIONAL STRUCTURE OF HLA-B27 AT 2.1 ANGSTROMS RESOLUTION SUGGESTS A GENERAL MECHANISM FOR TIGHT PEPTIDE BINDING TO MHC
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.

1hsa__assembly_1__model_1

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

Download this curve (.dat)

1hsa__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

1hsa__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	24.12 Å
Rg (electron density)	22.98 Å
Total Rg	23.84 Å
Atom count	3133
Residues	384
Excluded volume	54615 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`1hsa__assembly_1__model_1`	trimeric （3）	Success	4.1.3-1-20251215 (887e7ef)	View Download
2	1	`1hsa__assembly_2__model_1`	trimeric （3）	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 (4)

Entity 1 Entity 1 polymer

Description description	CLASS I HISTOCOMPATIBILITY ANTIGEN (HLA-B*2705)
Molecular weight formula_weight	31928.2 kDa
Source method src_method	man
Copy count entity_count	2

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	A,D
Atom count atom_count	6706

GSHSMRYFHTSVSRPGRGEPRFITVGYVDDTLFVRFDSDAASPREEPRAPWIEQEGPEYWDRETQICKAKAQTDREDLRTLLRYYNQSEAGSHTLQNMYGCDVGPDGRLLRGYHQDAYDGKDYIALNEDLSSWTAADTAAQITQRKWEAARVAEQLRAYLEGECVEWLRRYLENGKETLQRADPPKTHVTHHPISDHEATLRCWALGFYPAEITLTWQRDGEDQTQDTELVETRPAGDRTFQKWAAVVVPSGEEQRYTCHVQHEGLPKPLTLRWEP

Source Source

Source organism organism	Homo sapiens
Common name common_name	human
NCBI taxonomy ID ncbi_taxonomy_id	9606

Entity 2 Entity 2 polymer

Description description	BETA 2-MICROGLOBULIN
Molecular weight formula_weight	11748.2 kDa
Source method src_method	man
Copy count entity_count	2

Polymer Polymer

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

IQRTPKIQVYSRHPAENGKSNFLNCYVSGFHPSDIEVDLLKNGERIEKVEHSDLSFSKDWSFYLLYYTEFTPTEKDEYACRVNHVTLSQPKIVKWDRDM

Source Source

Source organism organism	Homo sapiens
Common name common_name	human
NCBI taxonomy ID ncbi_taxonomy_id	9606

Entity 3 Entity 3 polymer

Description description	MODEL PEPTIDE SEQUENCE - ARAAAAAAA
Molecular weight formula_weight	743.8 kDa
Source method src_method	man
Copy count entity_count	2

Polymer Polymer

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

ARAAAAAAA

Entity 4 Entity 4 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	440

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6. Fold Classification (SCOP + CATH) 12 domains

SCOP 2.08 (6 domains)

Domain ID domain_id	d1hsaa1
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	d1hsaa2
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	d1hsab_
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	d1hsad1
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	d1hsad2
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	d1hsae_
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 (6 domains)

Domain ID domain_id	1hsaA01
Class class	3 — Alpha Beta
Architecture architecture	30 — 2-Layer Sandwich
Topology topology	500 — Murine Class I Major Histocompatibility Complex, H2-DB; Chain A, domain 1
Homologous superfamily homologous superfamily	10 — MHC class I-like antigen recognition-like

Domain ID domain_id	1hsaA02
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	1hsaB00
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	1hsaD01
Class class	3 — Alpha Beta
Architecture architecture	30 — 2-Layer Sandwich
Topology topology	500 — Murine Class I Major Histocompatibility Complex, H2-DB; Chain A, domain 1
Homologous superfamily homologous superfamily	10 — MHC class I-like antigen recognition-like

Domain ID domain_id	1hsaD02
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	1hsaE00
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

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7. Citations (9)

The three-dimensional structure of HLA-B27 at 2.1 A resolution suggests a general mechanism for tight peptide binding to MHC.

Cell(Cambridge,Mass.) (1992)

PMID: 1525820 · DOI: 10.1016/0092-8674(92)90252-8 PRIMARY

Crystallization and Preliminary X-Ray Diffraction Studies of the Human Major Histocompatibility Antigen Hla-B27

Proteins (1992)

The Structure of Hla-B27 Reveals Nonamer Self-Peptides Bound in an Extended Conformation

Nature (1991)

Identification of Self Peptides Bound to Purified Hla-B27

Nature (1991)

Refined Structure of the Human Histocompatibility Antigen Hla-A2 at 2.6 Angstroms Resolution

J.Mol.Biol. (1991)

Specificity Pockets for the Side Chains of Peptide Antigens in Hla-Aw68

Nature (1989)

Structure of the Human Class I Histocompatibility Antigen, Hla-A2

Nature (1987)

The Foreign Antigen Binding Site and T Cell Recognition Regions of Class I Histocompatibility Antigens

Nature (1987)

Crystallization and X-Ray Diffraction Studies on the Histocompatibility Antigens Hla-A2 and Hla-A28 from Human Cell Membranes

J.Mol.Biol. (1985)

Unit-cell length a length_a	45.100 Å
Unit-cell length b length_b	69.800 Å
Unit-cell length c length_c	81.100 Å
Unit-cell angle α angle_alpha	80.30 °
Unit-cell angle β angle_beta	88.60 °
Unit-cell angle γ angle_gamma	89.90 °
Molecules per unit cell Z z_pdb	2

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

Resolution resolution	2.100 Å
Low-resolution limit resolution_low	— Å
R factor r_factor	0.2030
R_work r_work	0.2030
R_free r_free	—

THE THREE-DIMENSIONAL STRUCTURE OF HLA-B27 AT 2.1 ANGSTROMS RESOLUTION SUGGESTS A GENERAL MECHANISM FOR TIGHT PEPTIDE BINDING TO MHC

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

CLASS I HISTOCOMPATIBILITY ANTIGEN (HLA-B*2705)

State in the Current Structure

Other States of the Same Protein in the Database

BETA 2-MICROGLOBULIN

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

1hsa__assembly_1__model_1

1hsa__assembly_1__model_1 | I(q)

1hsa__assembly_1__model_1 | P(r) · Pending

4. Crystallography and Experiment 4. Crystallography & Experiment

Unit cell Unit Cell

Symmetry Symmetry

Refinement Refinement

5. Entities and Polymers Entities & Polymers (4)

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

Entity 4 Entity 4 water

6. Fold Classification (SCOP + CATH) 12 domains

SCOP 2.08 (6 domains)

CATH v4.4 (6 domains)

7. Citations (9)

THE THREE-DIMENSIONAL STRUCTURE OF HLA-B27 AT 2.1 ANGSTROMS RESOLUTION SUGGESTS A GENERAL MECHANISM FOR TIGHT PEPTIDE BINDING TO MHC

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

CLASS I HISTOCOMPATIBILITY ANTIGEN (HLA-B*2705)

State in the Current Structure

Other States of the Same Protein in the Database

Monomer

Homodimer

Homotetramer

Other homooligomers

Heteromeric or nucleic-acid complex

BETA 2-MICROGLOBULIN

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

1hsa__assembly_1__model_1

1hsa__assembly_1__model_1 | I(q)

1hsa__assembly_1__model_1 | P(r) · Pending

4. Crystallography and Experiment 4. Crystallography & Experiment

Unit cell Unit Cell

Symmetry Symmetry

Refinement Refinement

5. Entities and Polymers Entities & Polymers (4)

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

Entity 4 Entity 4 water

6. Fold Classification (SCOP + CATH) 12 domains

SCOP 2.08 (6 domains)

CATH v4.4 (6 domains)

7. Citations (9)