1kx3

X-Ray Structure of the Nucleosome Core Particle, NCP146, at 2.0 A Resolution

Method: X-RAY DIFFRACTION

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

histone H3

Xenopus laevis

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein–DNA	Heteromer	Protein 8 DNA 2	;DNA (5'(ATCAATATCCACCTGCAGATTCTACCAAAAGTGTATTTGGAAACTGCTCCATCAAAAGGCATGTTCAGCTGAATTCAGCTGAACATGCCTTTTGATGGAGCAGTTTCCAAATACACTTTTGGTAGAATCTGCAGGTGGATATTGAT)3') ; × 2 histone H4 × 2 （P62799） histone H2A.1 × 2 （P06897） histone H2B.2 × 2 （P02281） MANGANESE (II) ION × 13 water × 10	Consistent with all polymers

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	H31_XENLA
Isoform	—
PDB entities	2
Chains and sequence ranges	Author chain A； PDBConstruct 1–135； UniProt 1–135 Author chain E； PDBConstruct 1–135； UniProt 1–135

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 8 DNA 2	;DNA (5'(ATCAATATCCACCTGCAGATTCTACCAAAAGTGTATTTGGAAACTGCTCCATCAAAAGGCATGTTCAGCTGAATTCAGCTGAACATGCCTTTTGATGGAGCAGTTTCCAAATACACTTTTGGTAGAATCTGCAGGTGGATATTGAT)3') ; × 2 histone H3 × 2 （P84233） histone H2A.1 × 2 （P06897） histone H2B.2 × 2 （P02281） MANGANESE (II) ION × 13 water × 10	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	3
Chains and sequence ranges	Author chain B； PDBConstruct 1–102； UniProt 1–102 Author chain F； PDBConstruct 1–102； UniProt 1–102

histone H2A.1

Xenopus laevis

UniProt P06897

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein–DNA	Heteromer	Protein 8 DNA 2	;DNA (5'(ATCAATATCCACCTGCAGATTCTACCAAAAGTGTATTTGGAAACTGCTCCATCAAAAGGCATGTTCAGCTGAATTCAGCTGAACATGCCTTTTGATGGAGCAGTTTCCAAATACACTTTTGGTAGAATCTGCAGGTGGATATTGAT)3') ; × 2 histone H3 × 2 （P84233） histone H4 × 2 （P62799） histone H2B.2 × 2 （P02281） MANGANESE (II) ION × 13 water × 10	Consistent with all polymers

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	H2A1_XENLA
Isoform	—
PDB entities	4
Chains and sequence ranges	Author chain C； PDBConstruct 1–128； UniProt 1–129 Author chain G； PDBConstruct 1–128； UniProt 1–129

histone H2B.2

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 8 DNA 2	;DNA (5'(ATCAATATCCACCTGCAGATTCTACCAAAAGTGTATTTGGAAACTGCTCCATCAAAAGGCATGTTCAGCTGAATTCAGCTGAACATGCCTTTTGATGGAGCAGTTTCCAAATACACTTTTGGTAGAATCTGCAGGTGGATATTGAT)3') ; × 2 histone H3 × 2 （P84233） histone H4 × 2 （P62799） histone H2A.1 × 2 （P06897） MANGANESE (II) ION × 13 water × 10	Consistent with all polymers

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	H2B1_XENLA
Isoform	—
PDB entities	5
Chains and sequence ranges	Author chain D； PDBConstruct 1–125； UniProt 1–125 Author chain H； PDBConstruct 1–125； UniProt 1–125

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	1kx3
Deposition date deposition_date	2002-01-31
Structure title title	X-Ray Structure of the Nucleosome Core Particle, NCP146, at 2.0 A Resolution
Keywords keywords	;NUCLEOSOME, CHROMATIN, HISTONE, PROTEIN-DNA INTERACTION, NUCLEOPROTEIN, SUPERCOILED DNA, NUCLEOSOME CORE, PROTEIN-DNA COMPLEX, STRUCTURAL PROTEIN-DNA COMPLEX ;; STRUCTURAL PROTEIN/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.

1kx3__assembly_1__model_1

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

Download this curve (.dat)

1kx3__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

1kx3__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	39.75 Å
Rg (electron density)	37.04 Å
Total Rg	37.78 Å
Atom count	12080
Residues	1058
Excluded volume	197130 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`1kx3__assembly_1__model_1`	decameric （10）	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	;DNA (5'(ATCAATATCCACCTGCAGATTCTACCAAAAGTGTATTTGGAAACTGCTCCATCAAAAGGCATGTTCAGCTGAATTCAGCTGAACATGCCTTTTGATGGAGCAGTTTCCAAATACACTTTTGGTAGAATCTGCAGGTGGATATTGAT)3') ;
Molecular weight formula_weight	45053.9 kDa
Source method src_method	man
Copy count entity_count	2

Polymer Polymer

Polymer type type	polydeoxyribonucleotide
Chain IDs strand_id	I,J
Atom count atom_count	13023

ATCAATATCCACCTGCAGATTCTACCAAAAGTGTATTTGGAAACTGCTCCATCAAAAGGCATGTTCAGCTGAATTCAGCTGAACATGCCTTTTGATGGAGCAGTTTCCAAATACACTTTTGGTAGAATCTGCAGGTGGATATTGAT

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

Entity 2 Entity 2 polymer

Description description	histone H3
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

ARTKQTARKSTGGKAPRKQLATKAARKSAPATGGVKKPHRYRPGTVALREIRRYQKSTELLIRKLPFQRLVREIAQDFKTDLRFQSSAVMALQEASEAYLVALFEDTNLCAIHAKRVTIMPKDIQLARRIRGERA

Source Source

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

Entity 3 Entity 3 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	African clawed frog
NCBI taxonomy ID ncbi_taxonomy_id	8355
Host organism host_organism	Escherichia coli

Entity 4 Entity 4 polymer

Description description	histone H2A.1
Molecular weight formula_weight	13907.2 kDa
Source method src_method	man
Copy count entity_count	2

Polymer Polymer

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

SGRGKQGGKTRAKAKTRSSRAGLQFPVGRVHRLLRKGNYAERVGAGAPVYLAAVLEYLTAEILELAGNAARDNKKTRIIPRHLQLAVRNDEELNKLLGRVTIAQGGVLPNIQSVLLPKKTESSKSKSK

Source Source

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

Entity 5 Entity 5 polymer

Description description	histone H2B.2
Molecular weight formula_weight	13848.1 kDa
Source method src_method	man
Copy count entity_count	2

Polymer Polymer

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

PEPAKSAPAPKKGSKKAVTKTQKKDGKKRRKTRKESYAIYVYKVLKQVHPDTGISSKAMSIMNSFVNDVFERIAGEASRLAHYNKRSTITSREIQTAVRLLLPGELAKHAVSEGTKAVTKYTSAK

Source Source

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

Entity 6 Entity 6 non-polymer

Description description	MANGANESE (II) ION
Molecular weight formula_weight	54.9 kDa
Source method src_method	syn
Copy count entity_count	13

Entity 7 Entity 7 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	943

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6. Fold Classification (SCOP + CATH) 16 domains

SCOP 2.08 (8 domains)

Domain ID domain_id	d1kx3a_
Class class	a — All alpha proteins
Fold Fold fold	a.22 — Histone-fold
Superfamily Superfamily superfamily	a.22.1 — Histone-fold
Family Family family	a.22.1.1 — Nucleosome core histones

Domain ID domain_id	d1kx3b_
Class class	a — All alpha proteins
Fold Fold fold	a.22 — Histone-fold
Superfamily Superfamily superfamily	a.22.1 — Histone-fold
Family Family family	a.22.1.1 — Nucleosome core histones

Domain ID domain_id	d1kx3c_
Class class	a — All alpha proteins
Fold Fold fold	a.22 — Histone-fold
Superfamily Superfamily superfamily	a.22.1 — Histone-fold
Family Family family	a.22.1.1 — Nucleosome core histones

Domain ID domain_id	d1kx3d_
Class class	a — All alpha proteins
Fold Fold fold	a.22 — Histone-fold
Superfamily Superfamily superfamily	a.22.1 — Histone-fold
Family Family family	a.22.1.1 — Nucleosome core histones

Domain ID domain_id	d1kx3e_
Class class	a — All alpha proteins
Fold Fold fold	a.22 — Histone-fold
Superfamily Superfamily superfamily	a.22.1 — Histone-fold
Family Family family	a.22.1.1 — Nucleosome core histones

Domain ID domain_id	d1kx3f_
Class class	a — All alpha proteins
Fold Fold fold	a.22 — Histone-fold
Superfamily Superfamily superfamily	a.22.1 — Histone-fold
Family Family family	a.22.1.1 — Nucleosome core histones

Domain ID domain_id	d1kx3g_
Class class	a — All alpha proteins
Fold Fold fold	a.22 — Histone-fold
Superfamily Superfamily superfamily	a.22.1 — Histone-fold
Family Family family	a.22.1.1 — Nucleosome core histones

Domain ID domain_id	d1kx3h_
Class class	a — All alpha proteins
Fold Fold fold	a.22 — Histone-fold
Superfamily Superfamily superfamily	a.22.1 — Histone-fold
Family Family family	a.22.1.1 — Nucleosome core histones

CATH v4.4 (8 domains)

Domain ID domain_id	1kx3A00
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	1kx3B00
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	1kx3C00
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	1kx3D00
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	1kx3E00
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	1kx3F00
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	1kx3G00
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	1kx3H00
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	20 — Histone, subunit A
Homologous superfamily homologous superfamily	10 — Histone, subunit A

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Unit-cell length a length_a	105.400 Å
Unit-cell length b length_b	181.540 Å
Unit-cell length c length_c	109.600 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 21 21 21
Space-group number int_tables_number	19
Crystal system crystal_system	—

Resolution resolution	2.000 Å
Low-resolution limit resolution_low	6.000 Å
R factor r_factor	0.2410
R_work r_work	0.2400
R_free r_free	0.2750

X-Ray Structure of the Nucleosome Core Particle, NCP146, at 2.0 A Resolution

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

histone H3

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.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

histone H2B.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

2. Structure Basics 2. Structure Basics

3. Official assembly/model SAXS Official SAXS Profiles

1kx3__assembly_1__model_1

1kx3__assembly_1__model_1 | I(q)

1kx3__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

Source Source

Entity 6 Entity 6 non-polymer

Entity 7 Entity 7 water

6. Fold Classification (SCOP + CATH) 16 domains

SCOP 2.08 (8 domains)

CATH v4.4 (8 domains)

7. Citations (2)