SAXSdb — 2arp

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

Inhibin beta A 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 4	Follistatin × 2 （P21674） NICKEL (II) ION × 6 2-(2-{2-[2-(2-METHOXY-ETHOXY)-ETHOXY]-ETHOXY}-ETHOXY)-ETHANOL × 2 GLYCEROL × 8 water × 4	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	INHBA_HUMAN
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 1–116； UniProt 311–426

Follistatin

Rattus norvegicus

UniProt P21674

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein heterocomplex	Heteromer	Protein 4	Inhibin beta A chain × 2 （P08476） NICKEL (II) ION × 6 2-(2-{2-[2-(2-METHOXY-ETHOXY)-ETHOXY]-ETHOXY}-ETHOXY)-ETHANOL × 2 GLYCEROL × 8 water × 4	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	FST_RAT
Isoform	—
PDB entities	2
Chains and sequence ranges	Author chain F； PDBConstruct 4–152； UniProt 93–241

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	2arp
Deposition date deposition_date	2005-08-21
Structure title title	Activin A in complex with Fs12 fragment of follistatin
Keywords keywords	cystine knot, disulfide rich, egf domain, kazal domain, protein complex, HORMONE-GROWTH FACTOR COMPLEX; HORMONE/GROWTH FACTOR
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.

2arp__assembly_1__model_1

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

Download this curve (.dat)

2arp__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

2arp__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	28.93 Å
Rg (electron density)	27.92 Å
Total Rg	28.69 Å
Atom count	3978
Residues	506
Excluded volume	70634 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`2arp__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 (6)

Entity 1 Entity 1 polymer

Description description	Inhibin beta A chain
Molecular weight formula_weight	12991.9 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	2170

GLECDGKVNICCKKQFFVSFKDIGWNDWIIAPSGYHANYCEGECPSHIAGTSGSSLSFHSTVINHYRMRGHSPFANLKSCCVPTKLRPMSMLYYDDGQNIIKKDIQNMIVEECGCS

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 BL21(DE3)

Entity 2 Entity 2 polymer

Description description	Follistatin
Molecular weight formula_weight	16593.2 kDa
Source method src_method	man
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	F

GSMETCENVDCGPGKKCRMNKKNKPRCVCAPDCSNITWKGPVCGLDGKTYRNECALLKARCKEQPELEVQYQGKCKKTCRDVFCPGSSTCVVDQTNNAYCVTCNRICPEPSSSEQSLCGNDGVTYSSACHLRKATCLLGRSIGLAYEGKCIK

Source Source

Source organism organism	Rattus norvegicus
Common name common_name	Norway rat
NCBI taxonomy ID ncbi_taxonomy_id	10116
Host organism host_organism	Escherichia coli BL21(DE3)

Entity 3 Entity 3 non-polymer

Description description	NICKEL (II) ION
Molecular weight formula_weight	58.7 kDa
Source method src_method	syn
Copy count entity_count	3

Entity 4 Entity 4 non-polymer

Description description	2-(2-{2-[2-(2-METHOXY-ETHOXY)-ETHOXY]-ETHOXY}-ETHOXY)-ETHANOL
Molecular weight formula_weight	252.3 kDa
Source method src_method	syn
Copy count entity_count	1

Entity 5 Entity 5 non-polymer

Description description	GLYCEROL
Molecular weight formula_weight	92.1 kDa
Source method src_method	syn
Copy count entity_count	4

Entity 6 Entity 6 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) 4 domains

SCOP 2.08 (1 domains)

Domain ID domain_id	d2arpa_
Class class	g — Small proteins
Fold Fold fold	g.17 — Cystine-knot cytokines
Superfamily Superfamily superfamily	g.17.1 — Cystine-knot cytokines
Family Family family	g.17.1.2 — Transforming growth factor (TGF)-beta

CATH v4.4 (3 domains)

Domain ID domain_id	2arpA00
Class class	2 — Mainly Beta
Architecture architecture	10 — Ribbon
Topology topology	90 — Cystine Knot Cytokines, subunit B
Homologous superfamily homologous superfamily	10 — Cystine-knot cytokines

Domain ID domain_id	2arpF01
Class class	3 — Alpha Beta
Architecture architecture	30 — 2-Layer Sandwich
Topology topology	60 — Wheat Germ Agglutinin (Isolectin 2); domain 1
Homologous superfamily homologous superfamily	30 —

Domain ID domain_id	2arpF02
Class class	3 — Alpha Beta
Architecture architecture	30 — 2-Layer Sandwich
Topology topology	60 — Wheat Germ Agglutinin (Isolectin 2); domain 1
Homologous superfamily homologous superfamily	30 —

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Unit-cell length a length_a	79.297 Å
Unit-cell length b length_b	94.502 Å
Unit-cell length c length_c	44.873 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 2
Space-group number int_tables_number	18
Crystal system crystal_system	—

Resolution resolution	2.000 Å
Low-resolution limit resolution_low	25.800 Å
R factor r_factor	0.2019
R_work r_work	0.2019
R_free r_free	0.2540

Activin A in complex with Fs12 fragment of follistatin

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

Inhibin beta A chain

State in the Current Structure

Other States of the Same Protein in the Database

Follistatin

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

2arp__assembly_1__model_1

2arp__assembly_1__model_1 | I(q)

2arp__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 (6)

Entity 1 Entity 1 polymer

Polymer Polymer

Source Source

Entity 2 Entity 2 polymer

Polymer Polymer

Source Source

Entity 3 Entity 3 non-polymer

Entity 4 Entity 4 non-polymer

Entity 5 Entity 5 non-polymer

Entity 6 Entity 6 water

6. Fold Classification (SCOP + CATH) 4 domains

SCOP 2.08 (1 domains)

CATH v4.4 (3 domains)

7. Citations (1)

Activin A in complex with Fs12 fragment of follistatin

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

Inhibin beta A 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

Follistatin

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

2arp__assembly_1__model_1

2arp__assembly_1__model_1 | I(q)

2arp__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 (6)

Entity 1 Entity 1 polymer

Polymer Polymer

Source Source

Entity 2 Entity 2 polymer

Polymer Polymer

Source Source

Entity 3 Entity 3 non-polymer

Entity 4 Entity 4 non-polymer

Entity 5 Entity 5 non-polymer

Entity 6 Entity 6 water

6. Fold Classification (SCOP + CATH) 4 domains

SCOP 2.08 (1 domains)

CATH v4.4 (3 domains)

7. Citations (1)