SAXSdb — 1em8

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

DNA POLYMERASE III CHI SUBUNIT

Escherichia coli

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein heterocomplex	Heteromer	Protein 2	DNA POLYMERASE III PSI SUBUNIT × 1 （P28632） water × 2	Consistent with protein count
2	Protein heterocomplex	Heteromer	Protein 2	DNA POLYMERASE III PSI SUBUNIT × 1 （P28632） water × 2	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	HOLC_ECOLI
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 1–147； UniProt 1–147 Author chain C； PDBConstruct 1–147； UniProt 1–147

DNA POLYMERASE III PSI SUBUNIT

Escherichia coli

UniProt P28632

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein heterocomplex	Heteromer	Protein 2	DNA POLYMERASE III CHI SUBUNIT × 1 （P28905） water × 2	Consistent with protein count
2	Protein heterocomplex	Heteromer	Protein 2	DNA POLYMERASE III CHI SUBUNIT × 1 （P28905） water × 2	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	HOLD_ECOLI
Isoform	—
PDB entities	2
Chains and sequence ranges	Author chain B； PDBConstruct 1–112； UniProt 26–137 Author chain D； PDBConstruct 1–112； UniProt 26–137

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	1em8
Deposition date deposition_date	2000-03-16
Structure title title	Crystal structure of chi and psi subunit heterodimer from DNA POL III
Keywords keywords	DNA Pol III, heterodimer, clamp-loader, alpha-beta fold, GENE REGULATION; GENE REGULATION
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.

1em8__assembly_2__model_1

Assembly 2 · Model 1 · CRYSOL 4.1.3-1-20251215 (887e7ef)

Download this curve (.dat)

1em8__assembly_2__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

1em8__assembly_2__model_1 | P(r) · Pending

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

Rg（Guinier）	21.51 Å
Rg (electron density)	20.98 Å
Total Rg	21.81 Å
Atom count	1989
Residues	259
Excluded volume	35292 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`1em8__assembly_1__model_1`	dimeric （2）	Success	4.1.3-1-20251215 (887e7ef)	View Download
2	1	`1em8__assembly_2__model_1`	dimeric （2）	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 (3)

Entity 1 Entity 1 polymer

Description description	DNA POLYMERASE III CHI SUBUNIT
Molecular weight formula_weight	16653.7 kDa
EC 编号 ec_number	2.7.7.7
Source method src_method	man
Copy count entity_count	2

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	A,C
Atom count atom_count	4225

MKNATFYLLDNDTTVDGLSAVEQLVCEIAAERWRSGKRVLIACEDEKQAYRLDEALWARPAESFVPHNLAGEGPRGGAPVEIAWPQKRSSSRRDILISLRTSFADFATAFTEVVDFVPYEDSLKQLARERYKAYRVAGFNLNTATWK

Source Source

Source organism organism	Escherichia coli
NCBI taxonomy ID ncbi_taxonomy_id	562
Host organism host_organism	Escherichia coli

Entity 2 Entity 2 polymer

Description description	DNA POLYMERASE III PSI SUBUNIT
Molecular weight formula_weight	12203.8 kDa
EC 编号 ec_number	2.7.7.7
Source method src_method	man
Copy count entity_count	2

Polymer Polymer

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

QGEIAIAIPAHVRLVMVANDLPALTDPLVSDVLRALTVSPDQVLQLTPEKIAMLPQGSHCNSWRLGTDEPLSLEGAQVASPALTDLRANPTARAALWQQICTYEHDFFPRND

Source Source

Source organism organism	Escherichia coli
NCBI taxonomy ID ncbi_taxonomy_id	562
Host organism host_organism	Escherichia coli

Entity 3 Entity 3 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	256

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6. Fold Classification (SCOP + CATH) 8 domains

SCOP 2.08 (4 domains)

Domain ID domain_id	d1em8a_
Class class	c — Alpha and beta proteins (a/b)
Fold Fold fold	c.128 — DNA polymerase III chi subunit
Superfamily Superfamily superfamily	c.128.1 — DNA polymerase III chi subunit
Family Family family	c.128.1.1 — DNA polymerase III chi subunit

Domain ID domain_id	d1em8b_
Class class	c — Alpha and beta proteins (a/b)
Fold Fold fold	c.126 — DNA polymerase III psi subunit
Superfamily Superfamily superfamily	c.126.1 — DNA polymerase III psi subunit
Family Family family	c.126.1.1 — DNA polymerase III psi subunit

Domain ID domain_id	d1em8c_
Class class	c — Alpha and beta proteins (a/b)
Fold Fold fold	c.128 — DNA polymerase III chi subunit
Superfamily Superfamily superfamily	c.128.1 — DNA polymerase III chi subunit
Family Family family	c.128.1.1 — DNA polymerase III chi subunit

Domain ID domain_id	d1em8d_
Class class	c — Alpha and beta proteins (a/b)
Fold Fold fold	c.126 — DNA polymerase III psi subunit
Superfamily Superfamily superfamily	c.126.1 — DNA polymerase III psi subunit
Family Family family	c.126.1.1 — DNA polymerase III psi subunit

CATH v4.4 (4 domains)

Domain ID domain_id	1em8A00
Class class	3 — Alpha Beta
Architecture architecture	40 — 3-Layer(aba) Sandwich
Topology topology	50 — Rossmann fold
Homologous superfamily homologous superfamily	10110 — DNA polymerase III subunit chi

Domain ID domain_id	1em8B00
Class class	3 — Alpha Beta
Architecture architecture	40 — 3-Layer(aba) Sandwich
Topology topology	50 — Rossmann fold
Homologous superfamily homologous superfamily	10220 — DNA polymerase III, psi subunit

Domain ID domain_id	1em8C00
Class class	3 — Alpha Beta
Architecture architecture	40 — 3-Layer(aba) Sandwich
Topology topology	50 — Rossmann fold
Homologous superfamily homologous superfamily	10110 — DNA polymerase III subunit chi

Domain ID domain_id	1em8D00
Class class	3 — Alpha Beta
Architecture architecture	40 — 3-Layer(aba) Sandwich
Topology topology	50 — Rossmann fold
Homologous superfamily homologous superfamily	10220 — DNA polymerase III, psi subunit

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Unit-cell length a length_a	64.377 Å
Unit-cell length b length_b	65.719 Å
Unit-cell length c length_c	73.429 Å
Unit-cell angle α angle_alpha	90.00 °
Unit-cell angle β angle_beta	116.15 °
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	2.100 Å
Low-resolution limit resolution_low	20.000 Å
R factor r_factor	0.2330
R_work r_work	0.2290
R_free r_free	0.2650

Crystal structure of chi and psi subunit heterodimer from DNA POL III

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

DNA POLYMERASE III CHI SUBUNIT

State in the Current Structure

Other States of the Same Protein in the Database

DNA POLYMERASE III PSI SUBUNIT

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

1em8__assembly_2__model_1

1em8__assembly_2__model_1 | I(q)

1em8__assembly_2__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 (3)

Entity 1 Entity 1 polymer

Polymer Polymer

Source Source

Entity 2 Entity 2 polymer

Polymer Polymer

Source Source

Entity 3 Entity 3 water

6. Fold Classification (SCOP + CATH) 8 domains

SCOP 2.08 (4 domains)

CATH v4.4 (4 domains)

7. Citations (1)

Crystal structure of chi and psi subunit heterodimer from DNA POL III

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

DNA POLYMERASE III CHI SUBUNIT

State in the Current Structure

Other States of the Same Protein in the Database

Monomer

Homodimer

Homotetramer

Other homooligomers

Heteromeric or nucleic-acid complex

DNA POLYMERASE III PSI SUBUNIT

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

1em8__assembly_2__model_1

1em8__assembly_2__model_1 | I(q)

1em8__assembly_2__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 (3)

Entity 1 Entity 1 polymer

Polymer Polymer

Source Source

Entity 2 Entity 2 polymer

Polymer Polymer

Source Source

Entity 3 Entity 3 water

6. Fold Classification (SCOP + CATH) 8 domains

SCOP 2.08 (4 domains)

CATH v4.4 (4 domains)

7. Citations (1)