SAXSdb — 3bp4

▼

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

HLA class I histocompatibility antigen, B-27 alpha chain

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） nonameric peptide from Lysosomal protective protein × 1 （P10619） GLYCEROL × 2 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

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	HLA class I histocompatibility antigen, B-27 alpha chain × 1 （P03989） nonameric peptide from Lysosomal protective protein × 1 （P10619） GLYCEROL × 2 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 2–100； UniProt 21–119

nonameric peptide from Lysosomal protective protein

OrganismNot specified

UniProt P10619

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein heterocomplex	Heteromer	Protein 3	HLA class I histocompatibility antigen, B-27 alpha chain × 1 （P03989） Beta-2-microglobulin × 1 （P61769） GLYCEROL × 2 water × 3	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	PPGB_HUMAN
Isoform	—
PDB entities	3
Chains and sequence ranges	Author chain C； PDBConstruct 1–9； UniProt 2–10

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.

▼

2. Structure Basics 2. Structure Basics

Entry ID entry_id	3bp4
Deposition date deposition_date	2007-12-18
Structure title title	The high resolution crystal structure of HLA-B*2705 in complex with a Cathepsin A signal sequence peptide pCatA
Keywords keywords	;Major Histocompatibility Complex, MHC, Human Leukocyte Antigen, HLA, Beta-2-microglobulin, b2m, Cathepsin A, pCatA, Ankylosing Spondylitis, Glycoprotein, Host-virus interaction, Immune response, Membrane, MHC I, Transmembrane, Disease mutation, Glycation, Immunoglobulin domain, Pyrrolidone carboxylic acid, Secreted, Carboxypeptidase, Hydrolase, Lysosome, Protease, Zymogen, IMMUNE SYSTEM ;; IMMUNE SYSTEM
Experimental Method method	X-RAY DIFFRACTION

▼

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.

3bp4__assembly_1__model_1

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

Download this curve (.dat)

3bp4__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

3bp4__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	24.03 Å
Rg (electron density)	22.90 Å
Total Rg	23.76 Å
Atom count	3171
Residues	385
Excluded volume	55416 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`3bp4__assembly_1__model_1`	trimeric （3）	Success	4.1.3-1-20251215 (887e7ef)	View Download

▶

4. Crystallography and Experiment 4. Crystallography & Experiment

▶

5. Entities and Polymers Entities & Polymers (5)

Entity 1 Entity 1 polymer

Description description	HLA class I histocompatibility antigen, B-27 alpha chain
Molecular weight formula_weight	31928.2 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	3680

GSHSMRYFHTSVSRPGRGEPRFITVGYVDDTLFVRFDSDAASPREEPRAPWIEQEGPEYWDRETQICKAKAQTDREDLRTLLRYYNQSEAGSHTLQNMYGCDVGPDGRLLRGYHQDAYDGKDYIALNEDLSSWTAADTAAQITQRKWEAARVAEQLRAYLEGECVEWLRRYLENGKETLQRADPPKTHVTHHPISDHEATLRCWALGFYPAEITLTWQRDGEDQTQDTELVETRPAGDRTFQKWAAVVVPSGEEQRYTCHVQHEGLPKPLTLRWEP

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 2 Entity 2 polymer

Description description	Beta-2-microglobulin
Molecular weight formula_weight	11879.4 kDa
Source method src_method	man
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	B

MIQRTPKIQVYSRHPAENGKSNFLNCYVSGFHPSDIEVDLLKNGERIEKVEHSDLSFSKDWSFYLLYYTEFTPTEKDEYACRVNHVTLSQPKIVKWDRDM

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 3 Entity 3 polymer

Description description	nonameric peptide from Lysosomal protective protein
Molecular weight formula_weight	982.2 kDa
Source method src_method	syn
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	C

IRAAPPPLF

Entity 4 Entity 4 non-polymer

Description description	GLYCEROL
Molecular weight formula_weight	92.1 kDa
Source method src_method	syn
Copy count entity_count	2

Entity 5 Entity 5 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	502

▼

6. Fold Classification (SCOP + CATH) 5 domains

SCOP 2.08 (2 domains)

Domain ID domain_id	d3bp4b1
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	d3bp4b2
Class class	l — Artifacts
Fold Fold fold	l.1 — Tags
Superfamily Superfamily superfamily	l.1.1 — Tags
Family Family family	l.1.1.1 — Tags

CATH v4.4 (3 domains)

Domain ID domain_id	3bp4A01
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	3bp4A02
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	3bp4B00
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

▶

Unit-cell length a length_a	51.161 Å
Unit-cell length b length_b	82.400 Å
Unit-cell length c length_c	109.846 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	4

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

Resolution resolution	1.850 Å
Low-resolution limit resolution_low	46.630 Å
R factor r_factor	0.1750
R_work r_work	0.1730
R_free r_free	0.2220

The high resolution crystal structure of HLA-B*2705 in complex with a Cathepsin A signal sequence peptide pCatA

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

HLA class I histocompatibility antigen, B-27 alpha chain

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

nonameric peptide from Lysosomal protective protein

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

3bp4__assembly_1__model_1

3bp4__assembly_1__model_1 | I(q)

3bp4__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

Entity 4 Entity 4 non-polymer

Entity 5 Entity 5 water

6. Fold Classification (SCOP + CATH) 5 domains

SCOP 2.08 (2 domains)

CATH v4.4 (3 domains)

7. Citations (1)

The high resolution crystal structure of HLA-B*2705 in complex with a Cathepsin A signal sequence peptide pCatA

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

HLA class I histocompatibility antigen, B-27 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

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

nonameric peptide from Lysosomal protective protein

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

3bp4__assembly_1__model_1

3bp4__assembly_1__model_1 | I(q)

3bp4__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

Entity 4 Entity 4 non-polymer

Entity 5 Entity 5 water

6. Fold Classification (SCOP + CATH) 5 domains

SCOP 2.08 (2 domains)

CATH v4.4 (3 domains)

7. Citations (1)