2b5i

cytokine receptor complex

Method: X-RAY DIFFRACTION

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

Interleukin-2

Homo sapiens

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Other combination	Heteromer	Protein 4 其他Polymer 2	Interleukin-2 receptor beta chain × 1 （P14784） Cytokine receptor common gamma chain × 1 （P31785） Interleukin-2 receptor alpha chain × 1 （P01589） 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose × 2 2-acetamido-2-deoxy-beta-D-glucopyranose × 2 water × 4	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	IL2_HUMAN
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 1–133； UniProt 21–153

Interleukin-2 receptor beta chain

Homo sapiens

UniProt P14784

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Other combination	Heteromer	Protein 4 其他Polymer 2	Interleukin-2 × 1 （P60568） Cytokine receptor common gamma chain × 1 （P31785） Interleukin-2 receptor alpha chain × 1 （P01589） 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose × 2 2-acetamido-2-deoxy-beta-D-glucopyranose × 2 water × 4	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	IL2RB_HUMAN
Isoform	—
PDB entities	2
Chains and sequence ranges	Author chain B； PDBConstruct 1–214； UniProt 27–240

Cytokine receptor common gamma chain

Homo sapiens

UniProt P31785

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Other combination	Heteromer	Protein 4 其他Polymer 2	Interleukin-2 × 1 （P60568） Interleukin-2 receptor beta chain × 1 （P14784） Interleukin-2 receptor alpha chain × 1 （P01589） 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose × 2 2-acetamido-2-deoxy-beta-D-glucopyranose × 2 water × 4	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	IL2RG_HUMAN
Isoform	—
PDB entities	3
Chains and sequence ranges	Author chain C； PDBConstruct 1–199； UniProt 56–254

Interleukin-2 receptor alpha chain

Homo sapiens

UniProt P01589

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Other combination	Heteromer	Protein 4 其他Polymer 2	Interleukin-2 × 1 （P60568） Interleukin-2 receptor beta chain × 1 （P14784） Cytokine receptor common gamma chain × 1 （P31785） 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose × 2 2-acetamido-2-deoxy-beta-D-glucopyranose × 2 water × 4	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	IL2RA_HUMAN
Isoform	—
PDB entities	4
Chains and sequence ranges	Author chain D； PDBConstruct 1–217； UniProt 22–238

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	2b5i
Deposition date deposition_date	2005-09-28
Structure title title	cytokine receptor complex
Keywords keywords	four-helix bundle, Fibronectin domain, CYTOKINE-CYTOKINE RECEPTOR COMPLEX; CYTOKINE/CYTOKINE RECEPTOR
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.

2b5i__assembly_1__model_1

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

Download this curve (.dat)

2b5i__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

2b5i__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	31.61 Å
Rg (electron density)	30.69 Å
Total Rg	31.30 Å
Atom count	5292
Residues	629
Excluded volume	93880 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`2b5i__assembly_1__model_1`	tetrameric （4）	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 (7)

Entity 1 Entity 1 polymer

Description description	Interleukin-2
Molecular weight formula_weight	15436.0 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	5463

APTSSSTKKTQLQLEHLLLDLQMILNGINNYKNPKLTRMLTFKFYMPKKATELKHLQCLEEELKPLEEVLNLAQSKNFHLRPRDLISNINVIVLELKGSETTFMCEYADETATIVEFLNRWITFCQSIISTLT

Source Source

Source organism organism	Homo sapiens
Common name common_name	human
NCBI taxonomy ID ncbi_taxonomy_id	9606
Host organism host_organism	Trichoplusia ni

Entity 2 Entity 2 polymer

Description description	Interleukin-2 receptor beta chain
Molecular weight formula_weight	24761.1 kDa
Mutation mutation	N3Q,N17Q,N45Q
Source method src_method	man
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	B

AVQGTSQFTCFYNSRAQISCVWSQDGALQDTSCQVHAWPDRRRWQQTCELLPVSQASWACNLILGAPDSQKLTTVDIVTLRVLCREGVRWRVMAIQDFKPFENLRLMAPISLQVVHVETHRCNISWEISQASHYFERHLEFEARTLSPGHTWEEAPLLTLKQKQEWICLETLTPDTQYEFQVRVKPLQGEFTTWSPWSQPLAFRTKPAALGKDT

Source Source

Source organism organism	Homo sapiens
Common name common_name	human
NCBI taxonomy ID ncbi_taxonomy_id	9606
Host organism host_organism	Trichoplusia ni

Entity 3 Entity 3 polymer

Description description	Cytokine receptor common gamma chain
Molecular weight formula_weight	23912.7 kDa
Mutation mutation	N53Q
Source method src_method	man
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	C

PLPEVQCFVFNVEYMNCTWQSSSEPQPTNLTLHYWYKNSDNDKVQKCSHYLFSEEITSGCQLQKKEIHLYQTFVVQLQDPREPRRQATQMLKLQNLVIPWAPENLTLHKLSESQLELNWNNRFLNHCLEHLVQYRTDWDHSWTEQSVDYRHKFSLPSVDGQKRYTFRVRSRFNPLCGSAQHWSEWSHPIHWGSNTSKEN

Source Source

Source organism organism	Homo sapiens
Common name common_name	human
NCBI taxonomy ID ncbi_taxonomy_id	9606
Host organism host_organism	Trichoplusia ni

Entity 4 Entity 4 polymer

Description description	Interleukin-2 receptor alpha chain
Molecular weight formula_weight	24573.5 kDa
Mutation mutation	N68Q
Source method src_method	man
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	D

ELCDDDPPEIPHATFKAMAYKEGTMLNCECKRGFRRIKSGSLYMLCTGNSSHSSWDNQCQCTSSATRQTTKQVTPQPEEQKERKTTEMQSPMQPVDQASLPGHCREPPPWENEATERIYHFVVGQMVYYQCVQGYRALHRGPAESVCKMTHGKTRWTQPQLICTGEMETSQFPGEEKPQASPEGRPESETSCLVTTTDFQIQTEMAATMETSIFTTE

Source Source

Source organism organism	Homo sapiens
Common name common_name	human
NCBI taxonomy ID ncbi_taxonomy_id	9606
Host organism host_organism	Trichoplusia ni

Entity 5 Entity 5 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	2

Entity 6 Entity 6 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 7 Entity 7 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	171

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6. Fold Classification (SCOP + CATH) 14 domains

SCOP 2.08 (7 domains)

Domain ID domain_id	d2b5ia_
Class class	a — All alpha proteins
Fold Fold fold	a.26 — 4-helical cytokines
Superfamily Superfamily superfamily	a.26.1 — 4-helical cytokines
Family Family family	a.26.1.2 — Short-chain cytokines

Domain ID domain_id	d2b5ib1
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	d2b5ib2
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	d2b5ic1
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	d2b5ic2
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	d2b5id1
Class class	g — Small proteins
Fold Fold fold	g.18 — Complement control module/SCR domain
Superfamily Superfamily superfamily	g.18.1 — Complement control module/SCR domain
Family Family family	g.18.1.1 — Complement control module/SCR domain

Domain ID domain_id	d2b5id2
Class class	g — Small proteins
Fold Fold fold	g.18 — Complement control module/SCR domain
Superfamily Superfamily superfamily	g.18.1 — Complement control module/SCR domain
Family Family family	g.18.1.1 — Complement control module/SCR domain

CATH v4.4 (7 domains)

Domain ID domain_id	2b5iA00
Class class	1 — Mainly Alpha
Architecture architecture	20 — Up-down Bundle
Topology topology	1250 — Growth Hormone; Chain: A;
Homologous superfamily homologous superfamily	10 —

Domain ID domain_id	2b5iB01
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	2b5iB02
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	2b5iC01
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	2b5iC02
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	2b5iD01
Class class	2 — Mainly Beta
Architecture architecture	10 — Ribbon
Topology topology	70 — Complement Module; domain 1
Homologous superfamily homologous superfamily	10 — Complement Module, domain 1

Domain ID domain_id	2b5iD02
Class class	2 — Mainly Beta
Architecture architecture	20 — Single Sheet
Topology topology	28 — Rubrerythrin, domain 2
Homologous superfamily homologous superfamily	230 —

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Unit-cell length a length_a	113.913 Å
Unit-cell length b length_b	87.709 Å
Unit-cell length c length_c	130.177 Å
Unit-cell angle α angle_alpha	90.00 °
Unit-cell angle β angle_beta	116.32 °
Unit-cell angle γ angle_gamma	90.00 °
Molecules per unit cell Z z_pdb	4

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

Resolution resolution	2.300 Å
Low-resolution limit resolution_low	20.000 Å
R factor r_factor	0.2253
R_work r_work	0.2230
R_free r_free	0.2688

cytokine receptor complex

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

Interleukin-2

State in the Current Structure

Other States of the Same Protein in the Database

Monomer

Homodimer

Homotetramer

Other homooligomers

Heteromeric or nucleic-acid complex

Interleukin-2 receptor 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

Cytokine receptor common 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

Interleukin-2 receptor 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

2b5i__assembly_1__model_1

2b5i__assembly_1__model_1 | I(q)

2b5i__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 (7)

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

Source Source

Entity 4 Entity 4 polymer

Polymer Polymer

Source Source

Entity 5 Entity 5 branched

Entity 6 Entity 6 non-polymer

Entity 7 Entity 7 water

6. Fold Classification (SCOP + CATH) 14 domains

SCOP 2.08 (7 domains)

CATH v4.4 (7 domains)

7. Citations (1)