SAXSdb — 1qcb

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

PROTEIN (HEAT LABILE ENTEROTOXIN TYPE IIB B-PENTAMER)

Escherichia coli

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein homooligomer	Homooligomer	Protein 5	water × 5	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	E2BB_ECOLI
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain D； PDBConstruct 1–99； UniProt 24–122 Author chain E； PDBConstruct 1–99； UniProt 24–122 Author chain F； PDBConstruct 1–99； UniProt 24–122 Author chain G； PDBConstruct 1–99； UniProt 24–122 Author chain H； PDBConstruct 1–99； UniProt 24–122

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	1qcb
Deposition date deposition_date	1999-04-30
Structure title title	ESCHERICHIA COLI HEAT LABILE ENTEROTOXIN TYPE IIB B-PENTAMER
Keywords keywords	ENTEROTOXIN; ENTEROTOXIN
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.

1qcb__assembly_1__model_1

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

Download this curve (.dat)

1qcb__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

1qcb__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	24.15 Å
Rg (electron density)	22.82 Å
Total Rg	23.49 Å
Atom count	3750
Residues	495
Excluded volume	66341 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`1qcb__assembly_1__model_1`	pentameric （5）	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 (2)

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6. Fold Classification (SCOP + CATH) 10 domains

SCOP 2.08 (5 domains)

Domain ID domain_id	d1qcbd_
Class class	b — All beta proteins
Fold Fold fold	b.40 — OB-fold
Superfamily Superfamily superfamily	b.40.2 — Bacterial enterotoxins
Family Family family	b.40.2.1 — Bacterial AB5 toxins, B-subunits

Domain ID domain_id	d1qcbe_
Class class	b — All beta proteins
Fold Fold fold	b.40 — OB-fold
Superfamily Superfamily superfamily	b.40.2 — Bacterial enterotoxins
Family Family family	b.40.2.1 — Bacterial AB5 toxins, B-subunits

Domain ID domain_id	d1qcbf_
Class class	b — All beta proteins
Fold Fold fold	b.40 — OB-fold
Superfamily Superfamily superfamily	b.40.2 — Bacterial enterotoxins
Family Family family	b.40.2.1 — Bacterial AB5 toxins, B-subunits

Domain ID domain_id	d1qcbg_
Class class	b — All beta proteins
Fold Fold fold	b.40 — OB-fold
Superfamily Superfamily superfamily	b.40.2 — Bacterial enterotoxins
Family Family family	b.40.2.1 — Bacterial AB5 toxins, B-subunits

Domain ID domain_id	d1qcbh_
Class class	b — All beta proteins
Fold Fold fold	b.40 — OB-fold
Superfamily Superfamily superfamily	b.40.2 — Bacterial enterotoxins
Family Family family	b.40.2.1 — Bacterial AB5 toxins, B-subunits

CATH v4.4 (5 domains)

Domain ID domain_id	1qcbD00
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	50 — OB fold (Dihydrolipoamide Acetyltransferase, E2P)
Homologous superfamily homologous superfamily	50 —

Domain ID domain_id	1qcbE00
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	50 — OB fold (Dihydrolipoamide Acetyltransferase, E2P)
Homologous superfamily homologous superfamily	50 —

Domain ID domain_id	1qcbF00
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	50 — OB fold (Dihydrolipoamide Acetyltransferase, E2P)
Homologous superfamily homologous superfamily	50 —

Domain ID domain_id	1qcbG00
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	50 — OB fold (Dihydrolipoamide Acetyltransferase, E2P)
Homologous superfamily homologous superfamily	50 —

Domain ID domain_id	1qcbH00
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	50 — OB fold (Dihydrolipoamide Acetyltransferase, E2P)
Homologous superfamily homologous superfamily	50 —

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Unit-cell length a length_a	48.700 Å
Unit-cell length b length_b	69.000 Å
Unit-cell length c length_c	155.000 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	20

Space group space_group	P 21 21 21
Space-group number int_tables_number	19
Crystal system crystal_system	—

Resolution resolution	2.200 Å
Low-resolution limit resolution_low	20.000 Å
R factor r_factor	—
R_work r_work	0.1930
R_free r_free	0.2590

Description description	PROTEIN (HEAT LABILE ENTEROTOXIN TYPE IIB B-PENTAMER)
Molecular weight formula_weight	10778.2 kDa
Source method src_method	man
Copy count entity_count	5

Polymer type type	polypeptide(L)
Chain IDs strand_id	D,E,F,G,H
Atom count atom_count	3901

ESCHERICHIA COLI HEAT LABILE ENTEROTOXIN TYPE IIB B-PENTAMER

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

PROTEIN (HEAT LABILE ENTEROTOXIN TYPE IIB B-PENTAMER)

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

1qcb__assembly_1__model_1

1qcb__assembly_1__model_1 | I(q)

1qcb__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 (2)

Entity 1 Entity 1 polymer

Polymer Polymer

Source Source

Entity 2 Entity 2 water

6. Fold Classification (SCOP + CATH) 10 domains

SCOP 2.08 (5 domains)

CATH v4.4 (5 domains)

7. Citations (3)

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

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	151

ESCHERICHIA COLI HEAT LABILE ENTEROTOXIN TYPE IIB B-PENTAMER

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

PROTEIN (HEAT LABILE ENTEROTOXIN TYPE IIB B-PENTAMER)

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

1qcb__assembly_1__model_1

1qcb__assembly_1__model_1 | I(q)

1qcb__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 (2)

Entity 1 Entity 1 polymer

Polymer Polymer

Source Source

Entity 2 Entity 2 water

6. Fold Classification (SCOP + CATH) 10 domains

SCOP 2.08 (5 domains)

CATH v4.4 (5 domains)

7. Citations (3)