SAXSdb — 1n26

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

IL-6 Receptor alpha chain

Homo sapiens

State in the Current Structure

Assembly	Oligomeric State	Construct	Mutations and Modifications	Ligands, Ions and Associated Components	Method and Experimental Conditions	Structure Quality
1	Other combination Homooligomer Protein × 2 其他Polymer 4 PDB declaration: dimeric（2） Consistent with protein copy count	Chain A； UniProt 20–344	Fragment：IL-6R extral-cellular domains	;2-acetamido-2-deoxy-alpha-D-glucopyranose-(1-4)-alpha-D-mannopyranose-(1-6)-beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose ; × 2 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose × 2 NAG 2-acetamido-2-deoxy-beta-D-glucopyranose × 4 SO4 SULFATE ION × 4 CYS CYSTEINE × 2	X-RAY DIFFRACTION X-ray crystallization conditions：VAPOR DIFFUSION, HANGING DROP；pH 5.6；300 K；ammonium sulphate, PEG 3350, sodium citrate, pH 5.6, VAPOR DIFFUSION, HANGING DROP, temperature 300K	Resolution 2.40 Å R-free 0.290

Other States of the Same Protein in the Database

Each row is a biological assembly of the same UniProt protein in another PDB entry. The “Difference from current entry” column identifies evidence-level differences; no tag means the currently parsed fields agree.

Other PDB	Difference from Current Entry 1N26	Assembly / Oligomeric State	Construct	Mutations and Modifications	Ligands, Ions and Non-polymers	Method and Experimental Conditions	Structure Quality
1P9M Crystal structure of the hexameric human IL-6/IL-6 alpha receptor/gp130 complex Deposited 2003-05-12	Different construct Different oligomeric state Different ligand/ion Different experimental conditions Different structure-quality metrics	Assembly 1 Protein heterocomplex Heteromer；Protein × 6 PDB declaration: hexameric	Chain C 115–315（201 aa） Fragment：extracellular domains D2 - D3	Not recorded	No recorded non-water small molecule	X-RAY DIFFRACTION X-ray crystallization conditions VAPOR DIFFUSION, SITTING DROP；pH 4.5；293 K；Sodium formate, Sodium acetate, pH 4.5, VAPOR DIFFUSION, SITTING DROP, temperature 293K	Resolution 3.65 Å R-free 0.334
2ARW The solution structure of the membrane proximal cytokine receptor domain of the human interleukin-6 receptor Deposited 2005-08-22	Different construct Different oligomeric state Different ligand/ion Different experimental method Different experimental conditions Different structure-quality metrics	Assembly 1 Protein monomer Monomer；Protein × 1 PDB declaration: monomeric	Chain A 212–336（125 aa） Fragment：Third extracellular domain	Not recorded	No recorded non-water small molecule	SOLUTION NMR NMR measurement conditions pH 5；293 K；Ionic strength (raw mmCIF value) 50mM phosphate；Pressure ambient NMR sample composition 20mM phosphatebuffer pH 5.0, 95% H2O, 5% D2O \| 95% H2O/5% D2O	Resolution not provided
5FUC Biophysical and cellular characterisation of a junctional epitope antibody that locks IL-6 and gp80 together in a stable complex: implications for new therapeutic strategies Deposited 2016-01-25	Different construct Different mutation/modification Different oligomeric state Different ligand/ion Different experimental conditions Different structure-quality metrics	Assembly 1 Insufficient information Heteromer；Protein × 3 PDB declaration: trimeric	Chain D 111–322（212 aa） Fragment：RESIDUES 20-33 AND RESIDUES 111-322	Mutation：YES	NAG 2-acetamido-2-deoxy-beta-D-glucopyranose × 2	X-RAY DIFFRACTION X-ray crystallization conditions 0.1 M MES, PH 6.5, 14% PEG20K	Resolution 2.70 Å R-free 0.287
5FUC Biophysical and cellular characterisation of a junctional epitope antibody that locks IL-6 and gp80 together in a stable complex: implications for new therapeutic strategies Deposited 2016-01-25	Different construct Different mutation/modification Different oligomeric state Different ligand/ion Different experimental conditions Different structure-quality metrics	Assembly 2 Insufficient information Heteromer；Protein × 3 PDB declaration: trimeric	Chain C 111–322（212 aa） Fragment：RESIDUES 20-33 AND RESIDUES 111-322	Mutation：YES	NAG 2-acetamido-2-deoxy-beta-D-glucopyranose × 2	X-RAY DIFFRACTION X-ray crystallization conditions 0.1 M MES, PH 6.5, 14% PEG20K	Resolution 2.70 Å R-free 0.287
7DC8 Crystal structure of Switch Ab Fab and hIL6R in complex with ATP Deposited 2020-10-23	Different construct Different mutation/modification Different oligomeric state Different ligand/ion Different experimental conditions Different structure-quality metrics	Assembly 1 Protein heterocomplex Heteromer；Protein × 3 PDB declaration: trimeric	Chain C 111–320（210 aa）	Mutation：C193S	SO4 SULFATE ION × 5 ATP ADENOSINE-5'-TRIPHOSPHATE × 1	X-RAY DIFFRACTION X-ray crystallization conditions VAPOR DIFFUSION；pH 7.5；294 K；0.06 M Tris, 12.0 %(w/v) Polyethylene glycol 1500, 0.06 M Ammonium sulfate	Resolution 2.76 Å R-free 0.278
7DC8 Crystal structure of Switch Ab Fab and hIL6R in complex with ATP Deposited 2020-10-23	Different construct Different mutation/modification Different oligomeric state Different ligand/ion Different experimental conditions Different structure-quality metrics	Assembly 2 Protein heterocomplex Heteromer；Protein × 3 PDB declaration: trimeric	Chain F 111–320（210 aa）	Mutation：C193S	SO4 SULFATE ION × 5 ATP ADENOSINE-5'-TRIPHOSPHATE × 1	X-RAY DIFFRACTION X-ray crystallization conditions VAPOR DIFFUSION；pH 7.5；294 K；0.06 M Tris, 12.0 %(w/v) Polyethylene glycol 1500, 0.06 M Ammonium sulfate	Resolution 2.76 Å R-free 0.278
8D82 Cryo-EM structure of human IL-6 signaling complex in detergent: model containing full extracellular domains Deposited 2022-06-07	Different construct Different mutation/modification Different oligomeric state Different ligand/ion Different experimental method Different experimental conditions Different structure-quality metrics	Assembly 1 Other combination Heteromer；Protein × 6 PDB declaration: hexameric	Chain C 20–331（312 aa） Chain G 20–331（312 aa）	Not recorded	NAG 2-acetamido-2-deoxy-beta-D-glucopyranose × 18	ELECTRON MICROSCOPY cryo-EM buffer pH 7.5 cryo-EM vitrification conditions Cryogen ETHANE	Resolution 3.22 Å
8IOW Cryo-EM structure of the sarilumab Fab/IL-6R complex Deposited 2023-03-13	Different construct Different mutation/modification Different oligomeric state Different ligand/ion Different experimental method Different experimental conditions Different structure-quality metrics	Assembly 1 Protein heterocomplex Heteromer；Protein × 4 PDB declaration: tetrameric	Chain D2 1–365（365 aa） Chain I 1–365（365 aa）	Not recorded	NAG 2-acetamido-2-deoxy-beta-D-glucopyranose × 2	ELECTRON MICROSCOPY cryo-EM buffer pH 8 cryo-EM vitrification conditions Cryogen ETHANE	Resolution 3.20 Å
8J6F Cryo-EM structure of the Tocilizumab Fab/IL-6R complex Deposited 2023-04-25	Different construct Different mutation/modification Different oligomeric state Different ligand/ion Different experimental method Different experimental conditions Different structure-quality metrics	Assembly 1 Protein heterocomplex Heteromer；Protein × 4 PDB declaration: tetrameric	Chain B 122–131（10 aa） Chain I 1–365（365 aa）	Not recorded	NAG 2-acetamido-2-deoxy-beta-D-glucopyranose × 1	ELECTRON MICROSCOPY cryo-EM buffer pH 8 cryo-EM vitrification conditions Cryogen ETHANE	Resolution 3.30 Å
8QY5 Structure of interleukin 6. Deposited 2023-10-25	Different construct Different mutation/modification Different oligomeric state Different ligand/ion Different experimental method Different experimental conditions Different structure-quality metrics	Assembly 1 Other combination Heteromer；Protein × 6 PDB declaration: hexameric	Chain C 1–468（468 aa） Chain F 1–468（468 aa）	Not recorded	NAG 2-acetamido-2-deoxy-beta-D-glucopyranose × 2	ELECTRON MICROSCOPY cryo-EM buffer pH 7.2 cryo-EM vitrification conditions Cryogen ETHANE	Resolution 3.10 Å
8QY6 Structure of interleukin 6 (gp130 P496L mutant). Deposited 2023-10-25	Different construct Different mutation/modification Different oligomeric state Different ligand/ion Different experimental method Different experimental conditions Different structure-quality metrics	Assembly 1 Other combination Heteromer；Protein × 6 PDB declaration: hexameric	Chain C 1–468（468 aa） Chain F 1–468（468 aa）	Not recorded	NAG 2-acetamido-2-deoxy-beta-D-glucopyranose × 2	ELECTRON MICROSCOPY cryo-EM buffer pH 7.2 cryo-EM vitrification conditions Cryogen ETHANE	Resolution 3.16 Å

9 other PDB entries and 11 assemblies. Open the comparison page and filter oligomeric states

View Construct and Data Evidence

UniProt name	IL6A_HUMAN
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 1–325； UniProt 20–344

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	1n26
Deposition date deposition_date	2002-10-22
Structure title title	Crystal Structure of the extra-cellular domains of Human Interleukin-6 Receptor alpha chain
Keywords keywords	Transmembrane, Glycoprotein, Immunoglobulin domain, CYTOKINE; CYTOKINE
Experimental Method method	X-RAY DIFFRACTION

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3. SAXS Parameters (CRYSOL theoretical calculation) 3. SAXS Parameters (CRYSOL)

Radius of gyration Rg (Guinier) rg_guinier	30.07 Å
Radius of gyration Rg (electron density) rg_electron	30.19 Å
Forward intensity I(0) i0	22960900.00
Molecular weight molecular_weight	35584.0 kDa
Excluded volume excluded_volume	43895 Å³
Envelope volume envelope_volume	60982 Å³
Hydration-shell volume shell_volume	19451 Å³
Envelope diameter envelope_diameter	114.5 Å
Shell Rg shell_rg	32.42 Å
Envelope Rg envelope_rg	30.35 Å
Shape Rg shape_rg	30.21 Å
Total Rg total_rg	30.36 Å
Total atoms total_atoms	2497
Residues n_residues	299
Spherical-harmonic order n_harmonics	20
q range q_range	— – 0.5000 Å⁻¹
Data points n_points	101
Shell type shell_type	directional
Solvent electron density solvent_density	0.3340 e/Å³
Shell contrast contrast_shell	0.0300 e/Å³
CRYSOL version crysol_version	4.1.3

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4. P(r) Distance Distribution (GNOM inversion) 4. P(r) Analysis (GNOM)

Maximum dimension Dmax dmax	108.6 Å
Rg (real space) rg_real	30.54 Å
Rg uncertainty (real space) rg_real_error	1.33 Å
I(0) (real space) i0_real	2.2960e+07
I(0) uncertainty (real space) i0_real_error	4.7710e+05
Rg (reciprocal space) rg_reciprocal	30.34 Å
I(0) (reciprocal space) i0_reciprocal	22960000.0000
Solution quality estimate total_estimate	0.7508
Solution quality rating solution_quality	GOOD a GOOD solution
P(r) peaks n_peaks	2
Primary peak position r_peak_primary	20.5 Å
Skewness Skewness skewness	0.578
Kurtosis Kurtosis kurtosis	-0.350
Angular range angular_range	— – 0.2650 Å⁻¹
Current regularization parameter α current_alpha	0.0000
Highest regularization parameter α highest_alpha	2264000.0000
Real-space data points n_real_points	54
GNOM version gnom_version	4.1.3
Quality Criteria quality_criteria	AN1: 0.000; Oscil: 0.536; Stabil: 1.000; Sysdev: 1.000; Positv: 1.000; Valcen: 0.248; Smooth: 0.901

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5. Crystallography and Experiment 5. Crystallography & Experiment

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6. Entities and Polymers Entities & Polymers (7)

Entity 1 Entity 1 polymer

Description description	IL-6 Receptor alpha chain
Molecular weight formula_weight	36409.9 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	2580

LAPRRCPAQEVARGVLTSLPGDSVTLTCPGVEPEDNATVHWVLRKPAAGSHPSRWAGMGRRLLLRSVQLHDSGNYSCYRAGRPAGTVHLLVDVPPEEPQLSCFRKSPLSNVVCEWGPRSTPSLTTKAVLLVRKFQNSPAEDFQEPCQYSQESQKFSCQLAVPEGDSSFYIVSMCVASSVGSKFSKTQTFQGCGILQPDPPANITVTAVARNPRWLSVTWQDPHSWNSSFYRLRFELRYRAERSKTFTTWMVKDLQHHCVIHDAWSGLRHVVQLRAQEEFGQGEWSEWSPEAMGTPWTESRSPPAENEVSTPMQALTTNKDDDNIL

来源 Source

来源生物 organism	Homo sapiens
通用名 common_name	human
NCBI Class编号 ncbi_taxonomy_id	9606
宿主生物 host_organism	Cricetulus griseus

Entity 2 Entity 2 branched

Description description	;2-acetamido-2-deoxy-alpha-D-glucopyranose-(1-4)-alpha-D-mannopyranose-(1-6)-beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose ;
Molecular weight formula_weight	951.9 kDa
Source method src_method	man
Copy count entity_count	1

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	2

Entity 5 Entity 5 non-polymer

Description description	SULFATE ION
Molecular weight formula_weight	96.1 kDa
Source method src_method	syn
Copy count entity_count	2

Entity 6 Entity 6 non-polymer

Description description	CYSTEINE
Molecular weight formula_weight	121.2 kDa
Source method src_method	syn
Copy count entity_count	1

Entity 7 Entity 7 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	83

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7. Fold Classification (SCOP + CATH) 6 domains

SCOP 2.08 (3 domains)

Domain ID domain_id	d1n26a1
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.1.1.4 — I set domains

Domain ID domain_id	d1n26a2
Class class	b — All beta proteins
Fold Fold fold	b.1 — Immunoglobulin-like beta-sandwich
Superfamily Superfamily superfamily	b.1.2 — Fibronectin type III
Family Family family	b.1.2.1 — Fibronectin type III

Domain ID domain_id	d1n26a3
Class class	b — All beta proteins
Fold Fold fold	b.1 — Immunoglobulin-like beta-sandwich
Superfamily Superfamily superfamily	b.1.2 — Fibronectin type III
Family Family family	b.1.2.1 — Fibronectin type III

CATH v4.4 (3 domains)

Domain ID domain_id	1n26A01
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	1n26A02
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	1n26A03
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

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8. Citations (1)

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Unit-cell length a length_a	51.130 Å
Unit-cell length b length_b	51.130 Å
Unit-cell length c length_c	303.388 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	8

Space group space_group	P 43 21 2
Space-group number int_tables_number	96
Crystal system crystal_system	—

Resolution resolution	2.400 Å
Low-resolution limit resolution_low	6.000 Å
R factor r_factor	0.2200
R_work r_work	0.2200
R_free r_free	0.2900

fit	/app/data/saxs_computation/n2/1n26/1n26.fit
pddf	/app/data/pr_computation/n2/1n26/1n26.pr.out
profile	/app/data/saxs_computation/n2/1n26/1n26.dat

Crystal Structure of the extra-cellular domains of Human Interleukin-6 Receptor alpha chain