SAXSdb — 2p6a

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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 5	Follistatin × 2 （P19883） probable fragment of follistatin × 1	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 Author chain B； PDBConstruct 1–116； UniProt 311–426

Follistatin

Homo sapiens

UniProt P19883

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein heterocomplex	Heteromer	Protein 5	Inhibin beta A chain × 2 （P08476） probable fragment of follistatin × 1	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	FST_HUMAN
Isoform	—
PDB entities	2
Chains and sequence ranges	Author chain C； PDBConstruct 1–315； UniProt 30–344 Author chain D； PDBConstruct 1–315； UniProt 30–344

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	2p6a
Deposition date deposition_date	2007-03-16
Structure title title	The structure of the Activin:Follistatin 315 complex
Keywords keywords	Follistatin, Activin, Inhibin, TGF-beta, SIGNALING PROTEIN; SIGNALING PROTEIN
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.

2p6a__assembly_1__model_1

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

Download this curve (.dat)

2p6a__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

2p6a__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	32.46 Å
Rg (electron density)	31.77 Å
Total Rg	32.33 Å
Atom count	5952
Residues	816
Excluded volume	104360 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`2p6a__assembly_1__model_1`	pentameric （5）	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 (3)

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	2

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	A,B
Atom count atom_count	5952

GLECDGKVNICCKKQFFVSFKDIGWNDWIIAPSGYHANYCEGECPSHIAGTSGSSLSFHSTVINHYRMRGHSPFANLKSCCVPTKLRPMSMLYYDDGQNIIKKDIQNMIVEECGCS

Source Source

Source organism organism	Homo sapiens
Common name common_name	human
NCBI taxonomy ID ncbi_taxonomy_id	9606
Host organism host_organism	Cricetulus griseus

Entity 2 Entity 2 polymer

Description description	Follistatin
Molecular weight formula_weight	34796.4 kDa
Source method src_method	man
Copy count entity_count	2

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	D,C

GNCWLRQAKNGRCQVLYKTELSKEECCSTGRLSTSWTEEDVNDNTLFKWMIFNGGAPNCIPCKETCENVDCGPGKKCRMNKKNKPRCVCAPDCSNITWKGPVCGLDGKTYRNECALLKARCKEQPELEVQYQGRCKKTCRDVFCPGSSTCVVDQTNNAYCVTCNRICPEPASSEQYLCGNDGVTYSSACHLRKATCLLGRSIGLAYEGKCIKAKSCEDIQCTGGKKCLWDFKVGRGRCSLCDELCPDSKSDEPVCASDNATYASECAMKEAACSSGVLLEVKHSGSCNSISEDTEEEEEDEDQDYSFPISSILEW

Source Source

Source organism organism	Homo sapiens
Common name common_name	human
NCBI taxonomy ID ncbi_taxonomy_id	9606
Host organism host_organism	Cricetulus griseus

Entity 3 Entity 3 polymer

Description description	probable fragment of follistatin
Molecular weight formula_weight	728.8 kDa
Source method src_method	man
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	E

AAAAAAAAAA

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6. Fold Classification (SCOP + CATH) 10 domains

SCOP 2.08 (2 domains)

Domain ID domain_id	d2p6aa1
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

Domain ID domain_id	d2p6ab1
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 (8 domains)

Domain ID domain_id	2p6aA00
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	2p6aB00
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	2p6aC01
Class class	3 — Alpha Beta
Architecture architecture	90 — Alpha-Beta Complex
Topology topology	290 — Extracellular Matrix Fibrillin
Homologous superfamily homologous superfamily	10 — TGF-beta binding (TB) domain

Domain ID domain_id	2p6aC02
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	2p6aC03
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	2p6aC04
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	2p6aD01
Class class	3 — Alpha Beta
Architecture architecture	90 — Alpha-Beta Complex
Topology topology	290 — Extracellular Matrix Fibrillin
Homologous superfamily homologous superfamily	10 — TGF-beta binding (TB) domain

Domain ID domain_id	2p6aD02
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	104.641 Å
Unit-cell length b length_b	106.584 Å
Unit-cell length c length_c	87.568 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 2 2 21
Space-group number int_tables_number	17
Crystal system crystal_system	—

Resolution resolution	3.400 Å
Low-resolution limit resolution_low	31.010 Å
R factor r_factor	0.2250
R_work r_work	0.2230
R_free r_free	0.3240

The structure of the Activin:Follistatin 315 complex

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

2p6a__assembly_1__model_1

2p6a__assembly_1__model_1 | I(q)

2p6a__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 (3)

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

6. Fold Classification (SCOP + CATH) 10 domains

SCOP 2.08 (2 domains)

CATH v4.4 (8 domains)

7. Citations (1)

The structure of the Activin:Follistatin 315 complex

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

2p6a__assembly_1__model_1

2p6a__assembly_1__model_1 | I(q)

2p6a__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 (3)

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

6. Fold Classification (SCOP + CATH) 10 domains

SCOP 2.08 (2 domains)

CATH v4.4 (8 domains)

7. Citations (1)