SAXSdb — 1dd1

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

SMAD4

OrganismNot specified

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein homooligomer	Homooligomer	Protein 3	SULFATE ION × 9 water × 3	Consistent with protein count
2	Protein homooligomer	Homooligomer	Protein 6	SULFATE ION × 18 water × 6	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	SMAD4_HUMAN
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 1–268； UniProt 285–552 Author chain B； PDBConstruct 1–268； UniProt 285–552 Author chain C； PDBConstruct 1–268； UniProt 285–552

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	1dd1
Deposition date deposition_date	1999-11-05
Structure title title	CRYSTAL STRUCTURE ANALYSIS OF THE SMAD4 ACTIVE FRAGMENT
Keywords keywords	B-SHEET SANDWICH HELIX-TURN-HELIX, 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.

1dd1__assembly_1__model_1

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

Download this curve (.dat)

1dd1__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

1dd1__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	28.57 Å
Rg (electron density)	27.54 Å
Total Rg	28.32 Å
Atom count	5579
Residues	711
Excluded volume	98222 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`1dd1__assembly_1__model_1`	trimeric （3）	Success	4.1.3-1-20251215 (887e7ef)	View Download
2	1	`1dd1__assembly_2__model_1`	hexameric （6）	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)

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6. Fold Classification (SCOP + CATH) 6 domains

SCOP 2.08 (3 domains)

Domain ID domain_id	d1dd1a_
Class class	b — All beta proteins
Fold Fold fold	b.26 — SMAD/FHA domain
Superfamily Superfamily superfamily	b.26.1 — SMAD/FHA domain
Family Family family	b.26.1.1 — SMAD domain

Domain ID domain_id	d1dd1b_
Class class	b — All beta proteins
Fold Fold fold	b.26 — SMAD/FHA domain
Superfamily Superfamily superfamily	b.26.1 — SMAD/FHA domain
Family Family family	b.26.1.1 — SMAD domain

Domain ID domain_id	d1dd1c_
Class class	b — All beta proteins
Fold Fold fold	b.26 — SMAD/FHA domain
Superfamily Superfamily superfamily	b.26.1 — SMAD/FHA domain
Family Family family	b.26.1.1 — SMAD domain

CATH v4.4 (3 domains)

Domain ID domain_id	1dd1A00
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	200 — Tumour Suppressor Smad4
Homologous superfamily homologous superfamily	10 —

Domain ID domain_id	1dd1B00
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	200 — Tumour Suppressor Smad4
Homologous superfamily homologous superfamily	10 —

Domain ID domain_id	1dd1C00
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	200 — Tumour Suppressor Smad4
Homologous superfamily homologous superfamily	10 —

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Unit-cell length a length_a	142.433 Å
Unit-cell length b length_b	142.433 Å
Unit-cell length c length_c	195.478 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	48

Space group space_group	I 41 2 2
Space-group number int_tables_number	98
Crystal system crystal_system	—

Resolution resolution	2.620 Å
Low-resolution limit resolution_low	100.000 Å
R factor r_factor	0.2180
R_work r_work	0.2180
R_free r_free	0.1750

Description description	SMAD4
Molecular weight formula_weight	29418.4 kDa
Source method src_method	nat
Copy count entity_count	3

Polymer type type	polypeptide(L)
Chain IDs strand_id	A,B,C
Atom count atom_count	5889

CRYSTAL STRUCTURE ANALYSIS OF THE SMAD4 ACTIVE FRAGMENT

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

SMAD4

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

1dd1__assembly_1__model_1

1dd1__assembly_1__model_1 | I(q)

1dd1__assembly_1__model_1 | P(r) · Pending

4. Crystallography and Experiment 4. Crystallography & Experiment

Unit cell Unit Cell

Symmetry Symmetry

Refinement Refinement

5. Entities and Polymers Entities & Polymers (3)

Entity 1 Entity 1 polymer

Polymer Polymer

Entity 2 Entity 2 non-polymer

Entity 3 Entity 3 water

6. Fold Classification (SCOP + CATH) 6 domains

SCOP 2.08 (3 domains)

CATH v4.4 (3 domains)

7. Citations (1)

Description description	SULFATE ION
Molecular weight formula_weight	96.1 kDa
Source method src_method	syn
Copy count entity_count	9

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	302

CRYSTAL STRUCTURE ANALYSIS OF THE SMAD4 ACTIVE FRAGMENT

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

SMAD4

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

1dd1__assembly_1__model_1

1dd1__assembly_1__model_1 | I(q)

1dd1__assembly_1__model_1 | P(r) · Pending

4. Crystallography and Experiment 4. Crystallography & Experiment

Unit cell Unit Cell

Symmetry Symmetry

Refinement Refinement

5. Entities and Polymers Entities & Polymers (3)

Entity 1 Entity 1 polymer

Polymer Polymer

Entity 2 Entity 2 non-polymer

Entity 3 Entity 3 water

6. Fold Classification (SCOP + CATH) 6 domains

SCOP 2.08 (3 domains)

CATH v4.4 (3 domains)

7. Citations (1)