SAXSdb — 1k3e

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

CesT

Escherichia coli O157:H7

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein homooligomer	Homooligomer	Protein 2	No other associated polymer	Consistent with protein count
2	Protein homooligomer	Homooligomer	Protein 2	No other associated polymer	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	CEST_ECOLI
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 1–156； UniProt 1–156 Author chain B； PDBConstruct 1–156； UniProt 1–156

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	1k3e
Deposition date deposition_date	2001-10-02
Structure title title	Type III secretion chaperone CesT
Keywords keywords	Chaperone, Secretion, Type III, intimin receptor; CHAPERONE
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.

1k3e__assembly_1__model_1

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

Download this curve (.dat)

1k3e__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

1k3e__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	27.59 Å
Rg (electron density)	27.59 Å
Total Rg	28.01 Å
Atom count	2254
Residues	285
Excluded volume	40286 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`1k3e__assembly_1__model_1`	dimeric （2）	Success	4.1.3-1-20251215 (887e7ef)	View Download
2	1	`1k3e__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 (1)

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6. Fold Classification (SCOP + CATH) 6 domains

SCOP 2.08 (2 domains)

Domain ID domain_id	d1k3ea_
Class class	d — Alpha and beta proteins (a+b)
Fold Fold fold	d.198 — Secretion chaperone-like
Superfamily Superfamily superfamily	d.198.1 — Type III secretory system chaperone-like
Family Family family	d.198.1.1 — Type III secretory system chaperone

Domain ID domain_id	d1k3eb_
Class class	d — Alpha and beta proteins (a+b)
Fold Fold fold	d.198 — Secretion chaperone-like
Superfamily Superfamily superfamily	d.198.1 — Type III secretory system chaperone-like
Family Family family	d.198.1.1 — Type III secretory system chaperone

CATH v4.4 (4 domains)

Domain ID domain_id	1k3eA01
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	287 — Helix Hairpins
Homologous superfamily homologous superfamily	390 —

Domain ID domain_id	1k3eA02
Class class	3 — Alpha Beta
Architecture architecture	30 — 2-Layer Sandwich
Topology topology	1460 — Yope Regulator; Chain: A,
Homologous superfamily homologous superfamily	10 —

Domain ID domain_id	1k3eB01
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	287 — Helix Hairpins
Homologous superfamily homologous superfamily	390 —

Domain ID domain_id	1k3eB02
Class class	3 — Alpha Beta
Architecture architecture	30 — 2-Layer Sandwich
Topology topology	1460 — Yope Regulator; Chain: A,
Homologous superfamily homologous superfamily	10 —

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Unit-cell length a length_a	57.586 Å
Unit-cell length b length_b	77.856 Å
Unit-cell length c length_c	94.176 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	2.800 Å
Low-resolution limit resolution_low	15.000 Å
R factor r_factor	—
R_work r_work	0.2250
R_free r_free	0.2850

Description description	CesT
Molecular weight formula_weight	17694.9 kDa
Source method src_method	man
Copy count entity_count	2

Polymer type type	polypeptide(L)
Chain IDs strand_id	A,B
Atom count atom_count	2254

Type III secretion chaperone CesT

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

CesT

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

1k3e__assembly_1__model_1

1k3e__assembly_1__model_1 | I(q)

1k3e__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 (1)

Entity 1 Entity 1 polymer

Polymer Polymer

Source Source

6. Fold Classification (SCOP + CATH) 6 domains

SCOP 2.08 (2 domains)

CATH v4.4 (4 domains)

7. Citations (1)

Source organism organism	Escherichia coli O157:H7
NCBI taxonomy ID ncbi_taxonomy_id	83334
Host organism host_organism	Escherichia coli

Type III secretion chaperone CesT

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

CesT

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

1k3e__assembly_1__model_1

1k3e__assembly_1__model_1 | I(q)

1k3e__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 (1)

Entity 1 Entity 1 polymer

Polymer Polymer

Source Source

6. Fold Classification (SCOP + CATH) 6 domains

SCOP 2.08 (2 domains)

CATH v4.4 (4 domains)

7. Citations (1)