SAXSdb — 3tu4

▼

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

Histone H3.2

Xenopus laevis

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein–DNA	Heteromer	Protein 10 DNA 2	Histone H4 × 2 （P62799） Histone H2A × 2 （Q6AZJ8） Histone H2B 1.1 × 2 （P02281） DNA (146-MER) × 1 DNA (146-MER) × 1 Regulatory protein SIR3 × 2 （P06701）	Consistent with all polymers
2	Protein–DNA	Heteromer	Protein 8 DNA 2	Histone H4 × 2 （P62799） Histone H2A × 2 （Q6AZJ8） Histone H2B 1.1 × 2 （P02281） DNA (146-MER) × 1 DNA (146-MER) × 1	Consistent with all polymers

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	H32_XENLA
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 1–135； UniProt 2–136 Author chain E； PDBConstruct 1–135； UniProt 2–136

Histone H4

Xenopus laevis

UniProt P62799

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein–DNA	Heteromer	Protein 10 DNA 2	Histone H3.2 × 2 （P84233） Histone H2A × 2 （Q6AZJ8） Histone H2B 1.1 × 2 （P02281） DNA (146-MER) × 1 DNA (146-MER) × 1 Regulatory protein SIR3 × 2 （P06701）	Consistent with all polymers
2	Protein–DNA	Heteromer	Protein 8 DNA 2	Histone H3.2 × 2 （P84233） Histone H2A × 2 （Q6AZJ8） Histone H2B 1.1 × 2 （P02281） DNA (146-MER) × 1 DNA (146-MER) × 1	Consistent with all polymers

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	H4_XENLA
Isoform	—
PDB entities	2
Chains and sequence ranges	Author chain B； PDBConstruct 1–102； UniProt 2–103 Author chain F； PDBConstruct 1–102； UniProt 2–103

Histone H2A

Xenopus laevis

UniProt Q6AZJ8

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein–DNA	Heteromer	Protein 10 DNA 2	Histone H3.2 × 2 （P84233） Histone H4 × 2 （P62799） Histone H2B 1.1 × 2 （P02281） DNA (146-MER) × 1 DNA (146-MER) × 1 Regulatory protein SIR3 × 2 （P06701）	Consistent with all polymers
2	Protein–DNA	Heteromer	Protein 8 DNA 2	Histone H3.2 × 2 （P84233） Histone H4 × 2 （P62799） Histone H2B 1.1 × 2 （P02281） DNA (146-MER) × 1 DNA (146-MER) × 1	Consistent with all polymers

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	Q6AZJ8_XENLA
Isoform	—
PDB entities	3
Chains and sequence ranges	Author chain C； PDBConstruct 1–129； UniProt 2–130 Author chain G； PDBConstruct 1–129； UniProt 2–130

Histone H2B 1.1

Xenopus laevis

UniProt P02281

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein–DNA	Heteromer	Protein 10 DNA 2	Histone H3.2 × 2 （P84233） Histone H4 × 2 （P62799） Histone H2A × 2 （Q6AZJ8） DNA (146-MER) × 1 DNA (146-MER) × 1 Regulatory protein SIR3 × 2 （P06701）	Consistent with all polymers
2	Protein–DNA	Heteromer	Protein 8 DNA 2	Histone H3.2 × 2 （P84233） Histone H4 × 2 （P62799） Histone H2A × 2 （Q6AZJ8） DNA (146-MER) × 1 DNA (146-MER) × 1	Consistent with all polymers

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	H2B11_XENLA
Isoform	—
PDB entities	4
Chains and sequence ranges	Author chain D； PDBConstruct 1–122； UniProt 5–126 Author chain H； PDBConstruct 1–122； UniProt 5–126

Regulatory protein SIR3

Saccharomyces cerevisiae S288c

UniProt P06701

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein–DNA	Heteromer	Protein 10 DNA 2	Histone H3.2 × 2 （P84233） Histone H4 × 2 （P62799） Histone H2A × 2 （Q6AZJ8） Histone H2B 1.1 × 2 （P02281） DNA (146-MER) × 1 DNA (146-MER) × 1	Consistent with all polymers
3	Protein monomer	Monomer	Protein 1	No other associated polymer	Consistent with protein count
4	Protein monomer	Monomer	Protein 1	No other associated polymer	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	SIR3_YEAST
Isoform	—
PDB entities	7
Chains and sequence ranges	Author chain K； PDBConstruct 1–213； UniProt 1–213 Author chain L； PDBConstruct 1–213； UniProt 1–213

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	3tu4
Deposition date deposition_date	2011-09-15
Structure title title	Crystal structure of the Sir3 BAH domain in complex with a nucleosome core particle.
Keywords keywords	histones, nucleosome, gene silencing, Signaling Protein-Structural Protein-DNA complex; Signaling Protein/Structural Protein/DNA
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.

3tu4__assembly_1__model_1

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

Download this curve (.dat)

3tu4__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

3tu4__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	41.77 Å
Rg (electron density)	40.20 Å
Total Rg	40.64 Å
Atom count	15660
Residues	1491
Excluded volume	260040 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`3tu4__assembly_1__model_1`	dodecameric （12）	Success	4.1.3-1-20251215 (887e7ef)	View Download
2	1	`3tu4__assembly_2__model_1`	decameric （10）	Success	4.1.3-1-20251215 (887e7ef)	View Download
3	1	`3tu4__assembly_3__model_1`	monomeric （1）	Success	4.1.3-1-20251215 (887e7ef)	View Download
4	1	`3tu4__assembly_4__model_1`	monomeric （1）	Success	4.1.3-1-20251215 (887e7ef)	View Download

▶

4. Crystallography and Experiment 4. Crystallography & Experiment

▶

5. Entities and Polymers Entities & Polymers (7)

Entity 1 Entity 1 polymer

Description description	Histone H3.2
Molecular weight formula_weight	15303.9 kDa
Source method src_method	man
Copy count entity_count	2

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	A,E
Atom count atom_count	15660

ARTKQTARKSTGGKAPRKQLATKAARKSAPATGGVKKPHRYRPGTVALREIRRYQKSTELLIRKLPFQRLVREIAQDFKTDLRFQSSAVMALQEASEAYLVALFEDTNLCAIHAKRVTIMPKDIQLARRIRGERA

Source Source

Source organism organism	Xenopus laevis
Common name common_name	clawed frog,common platanna,platanna
NCBI taxonomy ID ncbi_taxonomy_id	8355
Host organism host_organism	Escherichia coli

Entity 2 Entity 2 polymer

Description description	Histone H4
Molecular weight formula_weight	11263.2 kDa
Source method src_method	man
Copy count entity_count	2

Polymer Polymer

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

SGRGKGGKGLGKGGAKRHRKVLRDNIQGITKPAIRRLARRGGVKRISGLIYEETRGVLKVFLENVIRDAVTYTEHAKRKTVTAMDVVYALKRQGRTLYGFGG

Source Source

Source organism organism	Xenopus laevis
Common name common_name	clawed frog,common platanna,platanna
NCBI taxonomy ID ncbi_taxonomy_id	8355
Host organism host_organism	Escherichia coli

Entity 3 Entity 3 polymer

Description description	Histone H2A
Molecular weight formula_weight	13978.2 kDa
Source method src_method	man
Copy count entity_count	2

Polymer Polymer

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

SGRGKQGGKTRAKAKTRSSRAGLQFPVGRVHRLLRKGNYAERVGAGAPVYLAAVLEYLTAEILELAGNAARDNKKTRIIPRHLQLAVRNDEELNKLLGRVTIAQGGVLPNIQSVLLPKKTESSKSAKSK

Source Source

Source organism organism	Xenopus laevis
Common name common_name	clawed frog,common platanna,platanna
NCBI taxonomy ID ncbi_taxonomy_id	8355
Host organism host_organism	Escherichia coli

Entity 4 Entity 4 polymer

Description description	Histone H2B 1.1
Molecular weight formula_weight	13524.8 kDa
Source method src_method	man
Copy count entity_count	2

Polymer Polymer

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

AKSAPAPKKGSKKAVTKTQKKDGKKRRKTRKESYAIYVYKVLKQVHPDTGISSKAMSIMNSFVNDVFERIAGEASRLAHYNKRSTITSREIQTAVRLLLPGELAKHAVSEGTKAVTKYTSAK

Source Source

Source organism organism	Xenopus laevis
Common name common_name	clawed frog,common platanna,platanna
NCBI taxonomy ID ncbi_taxonomy_id	8355
Host organism host_organism	Escherichia coli

Entity 5 Entity 5 polymer

Description description	DNA (146-MER)
Molecular weight formula_weight	45137.8 kDa
Source method src_method	syn
Copy count entity_count	1

Polymer Polymer

Polymer type type	polydeoxyribonucleotide
Chain IDs strand_id	I

ATCGAGAATCCCGGTGCCGAGGCCGCTCAATTGGTCGTAGACAGCTCTAGCACCGCTTAAACGCACGTACGGATTCTCCCCCGCGTTTTAACCGCCAAGGGGATTACTCCCTAGTCTCCAGGCACGTGTCAGATATATACATCCGAT

Entity 6 Entity 6 polymer

Description description	DNA (146-MER)
Molecular weight formula_weight	45609.1 kDa
Source method src_method	syn
Copy count entity_count	1

Polymer Polymer

Polymer type type	polydeoxyribonucleotide
Chain IDs strand_id	J

ATCGGATGTATATATCTGACACGTGCCTGGAGACTAGGGAGTAATCCCCTTGGCGGTTAAAACGCGGGGGAGAATCCGTACGTGCGTTTAAGCGGTGCTAGAGCTGTCTACGACCAATTGAGCGGCCTCGGCACCGGGATTCTCGAT

Entity 7 Entity 7 polymer

Description description	Regulatory protein SIR3
Molecular weight formula_weight	27263.9 kDa
Mutation mutation	D205N
Source method src_method	man
Copy count entity_count	2

Polymer Polymer

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

MAKTLKDLDGWQVIITDDQGRVIDDNNRRRSRKRGGENVFLKRISDGLSFGKGESVIFNDNVTETYSVYLIHEIRLNTLNNVVEIWVFSYLRWFELKPKLYYEQFRPDLIKEDHPLEFYKDKFFNEVNKSELYLTAELSEIWLKDFIAVGQILPESQWNDSSIDKIEDRDFLVRYACEPTAEKFVPIDIFQIIRRVKEMEPKQSNEYLKRVSVSVDKLAAALEHHHHHH

Source Source

Source organism organism	Saccharomyces cerevisiae S288c
Common name common_name	;Baker's yeast ;
NCBI taxonomy ID ncbi_taxonomy_id	559292
Host organism host_organism	Escherichia coli

▼

6. Fold Classification (SCOP + CATH) 10 domains

CATH v4.4 (10 domains)

Domain ID domain_id	3tu4A00
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	20 — Histone, subunit A
Homologous superfamily homologous superfamily	10 — Histone, subunit A

Domain ID domain_id	3tu4B00
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	20 — Histone, subunit A
Homologous superfamily homologous superfamily	10 — Histone, subunit A

Domain ID domain_id	3tu4C00
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	20 — Histone, subunit A
Homologous superfamily homologous superfamily	10 — Histone, subunit A

Domain ID domain_id	3tu4D00
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	20 — Histone, subunit A
Homologous superfamily homologous superfamily	10 — Histone, subunit A

Domain ID domain_id	3tu4E00
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	20 — Histone, subunit A
Homologous superfamily homologous superfamily	10 — Histone, subunit A

Domain ID domain_id	3tu4F00
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	20 — Histone, subunit A
Homologous superfamily homologous superfamily	10 — Histone, subunit A

Domain ID domain_id	3tu4G00
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	20 — Histone, subunit A
Homologous superfamily homologous superfamily	10 — Histone, subunit A

Domain ID domain_id	3tu4H00
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	20 — Histone, subunit A
Homologous superfamily homologous superfamily	10 — Histone, subunit A

Domain ID domain_id	3tu4K00
Class class	2 — Mainly Beta
Architecture architecture	30 — Roll
Topology topology	30 — SH3 type barrels.
Homologous superfamily homologous superfamily	490 — Bromo adjacent homology (BAH) domain

Domain ID domain_id	3tu4L00
Class class	2 — Mainly Beta
Architecture architecture	30 — Roll
Topology topology	30 — SH3 type barrels.
Homologous superfamily homologous superfamily	490 — Bromo adjacent homology (BAH) domain

▶

Unit-cell length a length_a	102.880 Å
Unit-cell length b length_b	102.880 Å
Unit-cell length c length_c	555.750 Å
Unit-cell angle α angle_alpha	90.00 °
Unit-cell angle β angle_beta	90.00 °
Unit-cell angle γ angle_gamma	120.00 °
Molecules per unit cell Z z_pdb	12

Space group space_group	P 61
Space-group number int_tables_number	169
Crystal system crystal_system	—

Resolution resolution	3.000 Å
Low-resolution limit resolution_low	44.548 Å
R factor r_factor	0.1932
R_work r_work	0.1919
R_free r_free	0.2406

Crystal structure of the Sir3 BAH domain in complex with a nucleosome core particle.

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

Histone H3.2

State in the Current Structure

Other States of the Same Protein in the Database

Monomer

Homodimer

Homotetramer

Other homooligomers

Heteromeric or nucleic-acid complex

Histone H4

State in the Current Structure

Other States of the Same Protein in the Database

Monomer

Homodimer

Homotetramer

Other homooligomers

Heteromeric or nucleic-acid complex

Histone H2A

State in the Current Structure

Other States of the Same Protein in the Database

Monomer

Homodimer

Homotetramer

Other homooligomers

Heteromeric or nucleic-acid complex

Histone H2B 1.1

State in the Current Structure

Other States of the Same Protein in the Database

Monomer

Homodimer

Homotetramer

Other homooligomers

Heteromeric or nucleic-acid complex

Regulatory protein SIR3

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

3tu4__assembly_1__model_1

3tu4__assembly_1__model_1 | I(q)

3tu4__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 (7)

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 polymer

Polymer Polymer

Source Source

Entity 5 Entity 5 polymer

Polymer Polymer

Entity 6 Entity 6 polymer

Polymer Polymer

Entity 7 Entity 7 polymer

Polymer Polymer

Source Source

6. Fold Classification (SCOP + CATH) 10 domains

CATH v4.4 (10 domains)

7. Citations (1)