SAXSdb — 1a6a

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

HLA class II histocompatibility antigen, DR alpha chain

OrganismNot specified

UniProt P01903

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 II histocompatibility antigen, DR-1 beta chain × 1 （P01912） HLA class II histocompatibility antigen, gamma chain × 1 （P04233） 2-acetamido-2-deoxy-beta-D-glucopyranose × 2 water × 3	Consistent with protein count
2	Protein heterocomplex	Heteromer	Protein 6	HLA class II histocompatibility antigen, DR-1 beta chain × 2 （P01912） HLA class II histocompatibility antigen, gamma chain × 2 （P04233） 2-acetamido-2-deoxy-beta-D-glucopyranose × 4 water × 6	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	2DRA_HUMAN
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 1–176； UniProt 30–205

HLA class II histocompatibility antigen, DR-1 beta chain

OrganismNot specified

UniProt P01912

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 II histocompatibility antigen, DR alpha chain × 1 （P01903） HLA class II histocompatibility antigen, gamma chain × 1 （P04233） 2-acetamido-2-deoxy-beta-D-glucopyranose × 2 water × 3	Consistent with protein count
2	Protein heterocomplex	Heteromer	Protein 6	HLA class II histocompatibility antigen, DR alpha chain × 2 （P01903） HLA class II histocompatibility antigen, gamma chain × 2 （P04233） 2-acetamido-2-deoxy-beta-D-glucopyranose × 4 water × 6	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	HB2B_HUMAN
Isoform	—
PDB entities	2
Chains and sequence ranges	Author chain B； PDBConstruct 1–187； UniProt 34–220

HLA class II histocompatibility antigen, gamma chain

OrganismNot specified

UniProt P04233

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 II histocompatibility antigen, DR alpha chain × 1 （P01903） HLA class II histocompatibility antigen, DR-1 beta chain × 1 （P01912） 2-acetamido-2-deoxy-beta-D-glucopyranose × 2 water × 3	Consistent with protein count
2	Protein heterocomplex	Heteromer	Protein 6	HLA class II histocompatibility antigen, DR alpha chain × 2 （P01903） HLA class II histocompatibility antigen, DR-1 beta chain × 2 （P01912） 2-acetamido-2-deoxy-beta-D-glucopyranose × 4 water × 6	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	HG2A_HUMAN
Isoform	—
PDB entities	3
Chains and sequence ranges	Author chain C； PDBConstruct 1–15； UniProt 103–117

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	1a6a
Deposition date deposition_date	1998-02-22
Structure title title	THE STRUCTURE OF AN INTERMEDIATE IN CLASS II MHC MATURATION: CLIP BOUND TO HLA-DR3
Keywords keywords	MHC GLYCOPROTEIN, COMPLEX (TRANSMEMBRANE-GLYCOPROTEIN), COMPLEX (TRANSMEMBRANE-GLYCOPROTEIN) complex; COMPLEX (TRANSMEMBRANE/GLYCOPROTEIN)
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.

1a6a__assembly_1__model_1

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

Download this curve (.dat)

1a6a__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

1a6a__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	24.79 Å
Rg (electron density)	23.92 Å
Total Rg	24.78 Å
Atom count	3136
Residues	378
Excluded volume	55420 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`1a6a__assembly_1__model_1`	trimeric （3）	Success	4.1.3-1-20251215 (887e7ef)	View Download
2	1	`1a6a__assembly_2__model_1`	hexameric （6）	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	HLA class II histocompatibility antigen, DR alpha chain
Molecular weight formula_weight	20469.2 kDa
Source method src_method	nat
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	A
Atom count atom_count	3158

HVIIQAEFYLNPDQSGEFMFDFDGDEIFHVDMAKKETVWRLEEFGRFASFEAQGALANIAVDKANLEIMTKRSNYTPITNVPPEVTVLTNSPVELREPNVLICFIDKFTPPVVNVTWLRNGKPVTTGVSETVFLPREDHLFRKFHYLPFLPSTEDVYDCRVEHWGLDEPLLKHWEF

Entity 2 Entity 2 polymer

Description description	HLA class II histocompatibility antigen, DR-1 beta chain
Molecular weight formula_weight	21935.4 kDa
Source method src_method	nat
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	B

PRFLEYSTSECHFFNGTERVRYLDRYFHNQEENVRFDSDVGEFRAVTELGRPDAEYWNSQKDLLEQKRGRVDNYCRHNYGVVESFTVQRRVHPKVTVYPSKTQPLQHHNLLVCSVSGFYPGSIEVRWFRNGQEEKTGVVSTGLIHNGDWTFQTLVMLETVPRSGEVYTCQVEHPSVTSPLTVEWRAR

Entity 3 Entity 3 polymer

Description description	HLA class II histocompatibility antigen, gamma chain
Molecular weight formula_weight	1676.1 kDa
Source method src_method	nat
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	C

PVSKMRMATPLLMQA

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	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	22

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6. Fold Classification (SCOP + CATH) 8 domains

SCOP 2.08 (4 domains)

Domain ID domain_id	d1a6aa1
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	d1a6aa2
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	d1a6ab1
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	d1a6ab2
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 (4 domains)

Domain ID domain_id	1a6aA01
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	1a6aA02
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	1a6aB01
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	1a6aB02
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	78.450 Å
Unit-cell length b length_b	78.450 Å
Unit-cell length c length_c	159.100 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	6

Space group space_group	P 32 1 2
Space-group number int_tables_number	153
Crystal system crystal_system	—

Resolution resolution	2.750 Å
Low-resolution limit resolution_low	6.000 Å
R factor r_factor	0.2460
R_work r_work	0.2460
R_free r_free	0.3250

THE STRUCTURE OF AN INTERMEDIATE IN CLASS II MHC MATURATION: CLIP BOUND TO HLA-DR3

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

HLA class II histocompatibility antigen, DR alpha chain

State in the Current Structure

Other States of the Same Protein in the Database

HLA class II histocompatibility antigen, DR-1 beta chain

State in the Current Structure

Other States of the Same Protein in the Database

HLA class II histocompatibility antigen, gamma 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

1a6a__assembly_1__model_1

1a6a__assembly_1__model_1 | I(q)

1a6a__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

Entity 2 Entity 2 polymer

Polymer Polymer

Entity 3 Entity 3 polymer

Polymer Polymer

Entity 4 Entity 4 non-polymer

Entity 5 Entity 5 water

6. Fold Classification (SCOP + CATH) 8 domains

SCOP 2.08 (4 domains)

CATH v4.4 (4 domains)

7. Citations (1)

THE STRUCTURE OF AN INTERMEDIATE IN CLASS II MHC MATURATION: CLIP BOUND TO HLA-DR3

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

HLA class II histocompatibility antigen, DR 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

HLA class II histocompatibility antigen, DR-1 beta 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

HLA class II histocompatibility antigen, gamma 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

1a6a__assembly_1__model_1

1a6a__assembly_1__model_1 | I(q)

1a6a__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

Entity 2 Entity 2 polymer

Polymer Polymer

Entity 3 Entity 3 polymer

Polymer Polymer

Entity 4 Entity 4 non-polymer

Entity 5 Entity 5 water

6. Fold Classification (SCOP + CATH) 8 domains

SCOP 2.08 (4 domains)

CATH v4.4 (4 domains)

7. Citations (1)