SAXSdb — 3h91

▼

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

Chromobox protein homolog 2

Homo sapiens

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein heterocomplex	Heteromer	Protein 4	H3K27 peptide × 2 water × 4	Consistent with protein count
2	Protein heterocomplex	Heteromer	Protein 2	H3K27 peptide × 1 water × 2	Consistent with protein count
3	Protein heterocomplex	Heteromer	Protein 4	H3K27 peptide × 2 water × 4	Consistent with protein count
4	Protein heterocomplex	Heteromer	Protein 2	H3K27 peptide × 1 water × 2	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	CBX2_HUMAN
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 1–54； UniProt 9–62 Author chain B； PDBConstruct 1–54； UniProt 9–62

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	3h91
Deposition date deposition_date	2009-04-29
Structure title title	Crystal structure of the complex of human chromobox homolog 2 (CBX2) and H3K27 peptide
Keywords keywords	;human chromobox homolog 2, CBX2, H3K27, Structural Genomics, Structural Genomics Consortium, SGC, Chromatin regulator, DNA-binding, Nucleus, Repressor, Transcription, Transcription regulation ;; TRANSCRIPTION
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.

3h91__assembly_1__model_1

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

Download this curve (.dat)

3h91__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

3h91__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	15.72 Å
Rg (electron density)	14.71 Å
Total Rg	16.02 Å
Atom count	1010
Residues	120
Excluded volume	18221 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`3h91__assembly_1__model_1`	tetrameric （4）	Success	4.1.3-1-20251215 (887e7ef)	View Download
2	1	`3h91__assembly_2__model_1`	dimeric （2）	Success	4.1.3-1-20251215 (887e7ef)	View Download
3	1	`3h91__assembly_3__model_1`	tetrameric （4）	Success	4.1.3-1-20251215 (887e7ef)	View Download
4	1	`3h91__assembly_4__model_1`	dimeric （2）	Success	4.1.3-1-20251215 (887e7ef)	View Download

▶

4. Crystallography and Experiment 4. Crystallography & Experiment

▶

5. Entities and Polymers Entities & Polymers (3)

Entity 1 Entity 1 polymer

Description description	Chromobox protein homolog 2
Molecular weight formula_weight	6511.6 kDa
Source method src_method	man
Copy count entity_count	2

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	A,B
Atom count atom_count	1206

EQVFAAECILSKRLRKGKLEYLVKWRGWSSKHNSWEPEENILDPRLLLAFQKKE

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	H3K27 peptide
Molecular weight formula_weight	1515.8 kDa
Source method src_method	syn
Copy count entity_count	2

Polymer Polymer

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

QLATKAARKSAPATG

Entity 3 Entity 3 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	152

▼

6. Fold Classification (SCOP + CATH) 4 domains

SCOP 2.08 (2 domains)

Domain ID domain_id	d3h91a_
Class class	b — All beta proteins
Fold Fold fold	b.34 — SH3-like barrel
Superfamily Superfamily superfamily	b.34.13 — Chromo domain-like
Family Family family	b.34.13.2 — Chromo domain

Domain ID domain_id	d3h91b_
Class class	b — All beta proteins
Fold Fold fold	b.34 — SH3-like barrel
Superfamily Superfamily superfamily	b.34.13 — Chromo domain-like
Family Family family	b.34.13.2 — Chromo domain

CATH v4.4 (2 domains)

Domain ID domain_id	3h91A00
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	50 — OB fold (Dihydrolipoamide Acetyltransferase, E2P)
Homologous superfamily homologous superfamily	40 —

Domain ID domain_id	3h91B00
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	50 — OB fold (Dihydrolipoamide Acetyltransferase, E2P)
Homologous superfamily homologous superfamily	40 —

▶

Unit-cell length a length_a	58.145 Å
Unit-cell length b length_b	84.013 Å
Unit-cell length c length_c	65.499 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	16

Space group space_group	C 2 2 21
Space-group number int_tables_number	20
Crystal system crystal_system	—

Resolution resolution	1.500 Å
Low-resolution limit resolution_low	19.990 Å
R factor r_factor	0.2102
R_work r_work	0.2094
R_free r_free	0.2230

Crystal structure of the complex of human chromobox homolog 2 (CBX2) and H3K27 peptide

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

Chromobox protein homolog 2

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

3h91__assembly_1__model_1

3h91__assembly_1__model_1 | I(q)

3h91__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

Source Source

Entity 2 Entity 2 polymer

Polymer Polymer

Entity 3 Entity 3 water

6. Fold Classification (SCOP + CATH) 4 domains

SCOP 2.08 (2 domains)

CATH v4.4 (2 domains)

7. Citations (1)

Crystal structure of the complex of human chromobox homolog 2 (CBX2) and H3K27 peptide

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

Chromobox protein homolog 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

3h91__assembly_1__model_1

3h91__assembly_1__model_1 | I(q)

3h91__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

Source Source

Entity 2 Entity 2 polymer

Polymer Polymer

Entity 3 Entity 3 water

6. Fold Classification (SCOP + CATH) 4 domains

SCOP 2.08 (2 domains)

CATH v4.4 (2 domains)

7. Citations (1)