SAXSdb — 1mhd

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

SMAD3

Homo sapiens

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein–DNA	Homooligomer	Protein 2 DNA 2	DNA × 1 DNA × 1 water × 4	Consistent with all polymers

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	SMAD3_HUMAN
Isoform	—
PDB entities	3
Chains and sequence ranges	Author chain A； PDBConstruct 1–132； UniProt 1–132 Author chain B； PDBConstruct 1–132； UniProt 1–132

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	1mhd
Deposition date deposition_date	1998-08-18
Structure title title	CRYSTAL STRUCTURE OF A SMAD MH1 DOMAIN BOUND TO DNA
Keywords keywords	COMPLEX (TRANSCRIPTION ACTIVATOR-DNA), SMAD3 MH1, SMAD BINDING ELEMENT, DNA, COMPLEX (TRANSCRIPTION ACTIVATOR-DNA) complex; COMPLEX (TRANSCRIPTION ACTIVATOR/DNA)
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.

1mhd__assembly_1__model_1

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

Download this curve (.dat)

1mhd__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

1mhd__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	23.64 Å
Rg (electron density)	23.87 Å
Total Rg	24.44 Å
Atom count	2590
Residues	273
Excluded volume	44544 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`1mhd__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 (4)

Entity 1 Entity 1 polymer

Description description	DNA
Molecular weight formula_weight	3959.6 kDa
Source method src_method	syn
Copy count entity_count	1

Polymer Polymer

Polymer type type	polydeoxyribonucleotide
Chain IDs strand_id	C
Atom count atom_count	2614

CAGTCTAGACATA

Entity 2 Entity 2 polymer

Description description	DNA
Molecular weight formula_weight	4294.8 kDa
Source method src_method	syn
Copy count entity_count	1

Polymer Polymer

Polymer type type	polydeoxyribonucleotide
Chain IDs strand_id	D

TATGTCTAGACTGA

Entity 3 Entity 3 polymer

Description description	SMAD3
Molecular weight formula_weight	15539.2 kDa
Source method src_method	man
Copy count entity_count	2

Polymer Polymer

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

MSSILPFTPPIVKRLLGWKKGEQNGQEEKWCEKAVKSLVKKLKKTGQLDELEKAITTQNVNTKCITIPRSLDGRLQVSHRKGLPHVIYCRLWRWPDLHSHHELRAMELCEFAFNMKKDEVCVNPYHYQRVET

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 4 Entity 4 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	24

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6. Fold Classification (SCOP + CATH) 4 domains

SCOP 2.08 (2 domains)

Domain ID domain_id	d1mhda_
Class class	d — Alpha and beta proteins (a+b)
Fold Fold fold	d.164 — SMAD MH1 domain
Superfamily Superfamily superfamily	d.164.1 — SMAD MH1 domain
Family Family family	d.164.1.1 — SMAD MH1 domain

Domain ID domain_id	d1mhdb_
Class class	d — Alpha and beta proteins (a+b)
Fold Fold fold	d.164 — SMAD MH1 domain
Superfamily Superfamily superfamily	d.164.1 — SMAD MH1 domain
Family Family family	d.164.1.1 — SMAD MH1 domain

CATH v4.4 (2 domains)

Domain ID domain_id	1mhdA00
Class class	3 — Alpha Beta
Architecture architecture	90 — Alpha-Beta Complex
Topology topology	520 — Smad3; Chain A
Homologous superfamily homologous superfamily	10 — SMAD MH1 domain

Domain ID domain_id	1mhdB00
Class class	3 — Alpha Beta
Architecture architecture	90 — Alpha-Beta Complex
Topology topology	520 — Smad3; Chain A
Homologous superfamily homologous superfamily	10 — SMAD MH1 domain

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Unit-cell length a length_a	45.600 Å
Unit-cell length b length_b	60.400 Å
Unit-cell length c length_c	71.600 Å
Unit-cell angle α angle_alpha	90.00 °
Unit-cell angle β angle_beta	102.00 °
Unit-cell angle γ angle_gamma	90.00 °
Molecules per unit cell Z z_pdb	4

Space group space_group	P 1 21 1
Space-group number int_tables_number	4
Crystal system crystal_system	—

Resolution resolution	2.800 Å
Low-resolution limit resolution_low	8.000 Å
R factor r_factor	0.2120
R_work r_work	0.2120
R_free r_free	0.2880

CRYSTAL STRUCTURE OF A SMAD MH1 DOMAIN BOUND TO DNA

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

SMAD3

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

1mhd__assembly_1__model_1

1mhd__assembly_1__model_1 | I(q)

1mhd__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

Entity 2 Entity 2 polymer

Polymer Polymer

Entity 3 Entity 3 polymer

Polymer Polymer

Source Source

Entity 4 Entity 4 water

6. Fold Classification (SCOP + CATH) 4 domains

SCOP 2.08 (2 domains)

CATH v4.4 (2 domains)

7. Citations (1)

CRYSTAL STRUCTURE OF A SMAD MH1 DOMAIN BOUND TO DNA

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

SMAD3

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

1mhd__assembly_1__model_1

1mhd__assembly_1__model_1 | I(q)

1mhd__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

Entity 2 Entity 2 polymer

Polymer Polymer

Entity 3 Entity 3 polymer

Polymer Polymer

Source Source

Entity 4 Entity 4 water

6. Fold Classification (SCOP + CATH) 4 domains

SCOP 2.08 (2 domains)

CATH v4.4 (2 domains)

7. Citations (1)