SAXSdb — 4ld9

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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） Widom 601 sequence reverse × 1 Widom 601 sequence forward × 1 Regulatory protein SIR3 × 2 （P06701）	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 1–136； UniProt 1–136 Author chain E； PDBConstruct 1–136； UniProt 1–136

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） Widom 601 sequence reverse × 1 Widom 601 sequence forward × 1 Regulatory protein SIR3 × 2 （P06701）	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 1–103； UniProt 1–103 Author chain F； PDBConstruct 1–103； UniProt 1–103

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） Widom 601 sequence reverse × 1 Widom 601 sequence forward × 1 Regulatory protein SIR3 × 2 （P06701）	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 1–130； UniProt 1–130 Author chain G； PDBConstruct 1–130； UniProt 1–130

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） Widom 601 sequence reverse × 1 Widom 601 sequence forward × 1 Regulatory protein SIR3 × 2 （P06701）	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 1–126； UniProt 1–126 Author chain H； PDBConstruct 1–126； UniProt 1–126

Regulatory protein SIR3

Saccharomyces cerevisiae

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） Widom 601 sequence reverse × 1 Widom 601 sequence forward × 1	Consistent with all polymers

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 2–229； UniProt 2–229 Author chain L； PDBConstruct 2–229； UniProt 2–229

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	4ld9
Deposition date deposition_date	2013-06-24
Structure title title	Crystal structure of the N-terminally acetylated BAH domain of Sir3 bound to the nucleosome core particle
Keywords keywords	;BETA BARREL, PROTEIN-DNA COMPLEX, DOUBLE HELIX, alpha-helix, beta-sheet, double stranded DNA, chromatin binding, chromatin, N-terminal acetylation, nucleus, NUCLEAR PROTEIN-TRANSCRIPTION-DNA complex ;; NUCLEAR PROTEIN/TRANSCRIPTION/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.

4ld9__assembly_1__model_1

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

Download this curve (.dat)

4ld9__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

4ld9__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)	40.24 Å
Total Rg	40.66 Å
Atom count	15140
Residues	1431
Excluded volume	251580 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`4ld9__assembly_1__model_1`	dodecameric （12）	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 (7)

Entity 1 Entity 1 polymer

Description description	Histone H3.2
Molecular weight formula_weight	15421.1 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	15140

MARTKQTARKSTGGKAPRKQLATKAARKSAPATGGVKKPHRYRPGTVALREIRRYQKSTELLIRKLPFQRLVREIAQDFKTDLRFQSSAVMALQEASEAYLVGLFEDTNLCAIHAKRVTIMPKDIQLARRIRGERA

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	11394.4 kDa
Source method src_method	man
Copy count entity_count	2

Polymer Polymer

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

MSGRGKGGKGLGKGGAKRHRKVLRDNIQGITKPAIRRLARRGGVKRISGLIYEETRGVLKVFLENVIRDAVTYTEHAKRKTVTAMDVVYALKRQGRTLYGFGG

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	14109.4 kDa
Source method src_method	man
Copy count entity_count	2

Polymer Polymer

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

MSGRGKQGGKTRAKAKTRSSRAGLQFPVGRVHRLLRKGNYAERVGAGAPVYLAAVLEYLTAEILELAGNAARDNKKTRIIPRHLQLAVRNDEELNKLLGRVTIAQGGVLPNIQSVLLPKKTESSKSAKSK

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	13965.3 kDa
Source method src_method	man
Copy count entity_count	2

Polymer Polymer

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

MPEPAKSAPAPKKGSKKAVTKTQKKDGKKRRKSRKESYAIYVYKVLKQVHPDTGISSKAMSIMNSFVNDVFERIAGEASRLAHYNKRSTITSREIQTAVRLLLPGELAKHAVSEGTKAVTKYTSAK

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	Widom 601 sequence reverse
Molecular weight formula_weight	51809.0 kDa
Source method src_method	syn
Copy count entity_count	1

Polymer Polymer

Polymer type type	polydeoxyribonucleotide
Chain IDs strand_id	I

CAATACATGCAATCGATGTATATATCTGACACGTGCCTGGAGACTAGGGAGTAATCCCCTTGGCGGTTAAAACGCGGGGGACAGCGCGTACGTGCGTTTAAGCGGTGCTAGAGCTGTCTACGACCAATTGAGCGGCCTCGGCACCGGGATTCTGCAGGGCGGCCGCG

Entity 6 Entity 6 polymer

Description description	Widom 601 sequence forward
Molecular weight formula_weight	51341.7 kDa
Source method src_method	syn
Copy count entity_count	1

Polymer Polymer

Polymer type type	polydeoxyribonucleotide
Chain IDs strand_id	J

CGCGGCCGCCCTGGAGAATCCCGGTGCCGAGGCCGCTCAATTGGTCGTAGACAGCTCTAGCACCGCTTAAACGCACGTACGCGCTGTCCCCCGCGTTTTAACCGCCAAGGGGATTACTCCCTAGTCTCCAGGCACGTGTCAGATATATACATCGATTGCATGTATTG

Entity 7 Entity 7 polymer

Description description	Regulatory protein SIR3
Molecular weight formula_weight	28073.9 kDa
Source method src_method	man
Copy count entity_count	2

Polymer Polymer

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

XAKTLKDLDGWQVIITDDQGRVIDDNNRRRSRKRGGENVFLKRISDGLSFGKGESVIFNDNVTETYSVYLIHEIRLNTLNNVVEIWVFSYLRWFELKPKLYYEQFRPDLIKEDHPLEFYKDKFFNEVNKSELYLTAELSEIWLKDFIAVGQILPESQWNDSSIDKIEDRDFLVRYACEPTAEKFVPIDIFQIIRRVKEMEPKQSDEYLKRVSVPVSGQKTNRQVMHKMGKHHHHHH

Source Source

Source organism organism	Saccharomyces cerevisiae
Common name common_name	;Baker's yeast ;
NCBI taxonomy ID ncbi_taxonomy_id	559292
Host organism host_organism	Spodoptera frugiperda

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6. Fold Classification (SCOP + CATH) 10 domains

CATH v4.4 (10 domains)

Domain ID domain_id	4ld9A00
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	4ld9B00
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	4ld9C00
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	4ld9D00
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	4ld9E00
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	4ld9F00
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	4ld9G00
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	4ld9H00
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	4ld9K00
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	4ld9L00
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

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Unit-cell length a length_a	105.513 Å
Unit-cell length b length_b	105.513 Å
Unit-cell length c length_c	488.225 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	3.306 Å
Low-resolution limit resolution_low	19.997 Å
R factor r_factor	0.2405
R_work r_work	0.2376
R_free r_free	0.2946

Crystal structure of the N-terminally acetylated BAH domain of Sir3 bound to the 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

4ld9__assembly_1__model_1

4ld9__assembly_1__model_1 | I(q)

4ld9__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)