3nfp

Crystal structure of the Fab fragment of therapeutic antibody daclizumab in complex with IL-2Ra (CD25) ectodomain

Method: X-RAY DIFFRACTION

▼

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

Interleukin-2 receptor subunit alpha

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	Heavy chain of Fab fragment of daclizumab × 1 Light chain of Fab fragment of daclizumab × 1 water × 3	Consistent with protein count
2	Protein heterocomplex	Heteromer	Protein 3	Heavy chain of Fab fragment of daclizumab × 1 Light chain of Fab fragment of daclizumab × 1 water × 3	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	3
Chains and sequence ranges	Author chain I； PDBConstruct 1–217； UniProt 22–238 Author chain K； 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.

▼

2. Structure Basics 2. Structure Basics

Entry ID entry_id	3nfp
Deposition date deposition_date	2010-06-10
Structure title title	Crystal structure of the Fab fragment of therapeutic antibody daclizumab in complex with IL-2Ra (CD25) ectodomain
Keywords keywords	IL-2Ra, CD25, Daclizumab, Zenapax, therapeutic antibody, immune system, Immune system-Cytokine complex; Immune system/Cytokine
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.

3nfp__assembly_1__model_1

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

Download this curve (.dat)

3nfp__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

3nfp__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	30.01 Å
Rg (electron density)	29.41 Å
Total Rg	30.06 Å
Atom count	4108
Residues	536
Excluded volume	72444 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`3nfp__assembly_1__model_1`	trimeric （3）	Success	4.1.3-1-20251215 (887e7ef)	View Download
2	1	`3nfp__assembly_2__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 (4)

Entity 1 Entity 1 polymer

Description description	Heavy chain of Fab fragment of daclizumab
Molecular weight formula_weight	23034.7 kDa
Source method src_method	man
Copy count entity_count	2

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	A,H
Atom count atom_count	8421

QVQLVQSGAEVKKPGSSVKVSCKASGYTFTSYRMHWVRQAPGQGLEWIGYINPSTGYTEYNQKFKDKATITADESTNTAYMELSSLRSEDTAVYYCARGGGVFDYWGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEP

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	Light chain of Fab fragment of daclizumab
Molecular weight formula_weight	23134.7 kDa
Source method src_method	man
Copy count entity_count	2

Polymer Polymer

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

DIQMTQSPSTLSASVGDRVTITCSASSSISYMHWYQQKPGKAPKLLIYTTSNLASGVPARFSGSGSGTEFTLTISSLQPDDFATYYCHQRSTYPLTFGQGTKVEVKRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGE

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	Interleukin-2 receptor subunit alpha
Molecular weight formula_weight	25388.3 kDa
Source method src_method	man
Copy count entity_count	2

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	I,K

ELCDDDPPEIPHATFKAMAYKEGTMLNCECKRGFRRIKSGSLYMLCTGNSSHSSWDNQCQCTSSATRNTTKQVTPQPEEQKERKTTEMQSPMQPVDQASLPGHCREPPPWENEATERIYHFVVGQMVYYQCVQGYRALHRGPAESVCKMTHGKTRWTQPQLICTGEMETSQFPGEEKPQASPEGRPESETSCLVTTTDFQIQTEMAATMETSIFTTEHHHHHH

Source Source

Source organism organism	Homo sapiens
Common name common_name	human
NCBI taxonomy ID ncbi_taxonomy_id	9606
Host organism host_organism	Spodoptera frugiperda

Entity 4 Entity 4 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	97

▼

6. Fold Classification (SCOP + CATH) 22 domains

SCOP 2.08 (10 domains)

Domain ID domain_id	d3nfpa_
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.1.1.0 — automated matches

Domain ID domain_id	d3nfpb1
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.1.1.0 — automated matches

Domain ID domain_id	d3nfpb2
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	d3nfph_
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.1.1.0 — automated matches

Domain ID domain_id	d3nfpi1
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	d3nfpi2
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	d3nfpk1
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	d3nfpk2
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	d3nfpl1
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.1.1.0 — automated matches

Domain ID domain_id	d3nfpl2
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 (12 domains)

Domain ID domain_id	3nfpA01
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	3nfpA02
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	3nfpB01
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	3nfpB02
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	3nfpH01
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	3nfpH02
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	3nfpI01
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	3nfpI02
Class class	2 — Mainly Beta
Architecture architecture	20 — Single Sheet
Topology topology	28 — Rubrerythrin, domain 2
Homologous superfamily homologous superfamily	230 —

Domain ID domain_id	3nfpK01
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	3nfpK02
Class class	2 — Mainly Beta
Architecture architecture	20 — Single Sheet
Topology topology	28 — Rubrerythrin, domain 2
Homologous superfamily homologous superfamily	230 —

Domain ID domain_id	3nfpL01
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	3nfpL02
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	102.167 Å
Unit-cell length b length_b	114.973 Å
Unit-cell length c length_c	247.555 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	16

Space group space_group	C 2 2 21
Space-group number int_tables_number	20
Crystal system crystal_system	—

Resolution resolution	2.860 Å
Low-resolution limit resolution_low	50.000 Å
R factor r_factor	0.2550
R_work r_work	0.2530
R_free r_free	0.3010

Crystal structure of the Fab fragment of therapeutic antibody daclizumab in complex with IL-2Ra (CD25) ectodomain

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

Interleukin-2 receptor subunit alpha

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

3nfp__assembly_1__model_1

3nfp__assembly_1__model_1 | I(q)

3nfp__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 (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

Source Source

Entity 4 Entity 4 water

6. Fold Classification (SCOP + CATH) 22 domains

SCOP 2.08 (10 domains)

CATH v4.4 (12 domains)

7. Citations (1)

Crystal structure of the Fab fragment of therapeutic antibody daclizumab in complex with IL-2Ra (CD25) ectodomain

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

Interleukin-2 receptor subunit alpha

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

3nfp__assembly_1__model_1

3nfp__assembly_1__model_1 | I(q)

3nfp__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 (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

Source Source

Entity 4 Entity 4 water

6. Fold Classification (SCOP + CATH) 22 domains

SCOP 2.08 (10 domains)

CATH v4.4 (12 domains)

7. Citations (1)