1r4q

Shiga toxin

Method: X-RAY DIFFRACTION

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

SHT cytotoxin A subunit

Shigella dysenteriae

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein heterocomplex	Heteromer	Protein 6	Shigella toxin chain B × 5 （Q7BQ98） water × 6	Consistent with protein count
2	Protein heterocomplex	Heteromer	Protein 6	Shigella toxin chain B × 5 （Q7BQ98） water × 6	Consistent with protein count
3	Protein heterocomplex	Heteromer	Protein 12	Shigella toxin chain B × 10 （Q7BQ98） water × 12	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	Q7BQ99_SHIDY
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 1–293； UniProt 23–315 Author chain L； PDBConstruct 1–293； UniProt 23–315

Shigella toxin chain B

Shigella dysenteriae

UniProt Q7BQ98

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein heterocomplex	Heteromer	Protein 6	SHT cytotoxin A subunit × 1 （Q7BQ99） water × 6	Consistent with protein count
2	Protein heterocomplex	Heteromer	Protein 6	SHT cytotoxin A subunit × 1 （Q7BQ99） water × 6	Consistent with protein count
3	Protein heterocomplex	Heteromer	Protein 12	SHT cytotoxin A subunit × 2 （Q7BQ99） water × 12	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	Q7BQ98_SHIDY
Isoform	—
PDB entities	2
Chains and sequence ranges	Author chain B； PDBConstruct 1–69； UniProt 21–89 Author chain C； PDBConstruct 1–69； UniProt 21–89 Author chain D； PDBConstruct 1–69； UniProt 21–89 Author chain E； PDBConstruct 1–69； UniProt 21–89 Author chain F； PDBConstruct 1–69； UniProt 21–89 Author chain G； PDBConstruct 1–69； UniProt 21–89 Author chain H； PDBConstruct 1–69； UniProt 21–89 Author chain I； PDBConstruct 1–69； UniProt 21–89 Author chain J； PDBConstruct 1–69； UniProt 21–89 Author chain K； PDBConstruct 1–69； UniProt 21–89

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	1r4q
Deposition date deposition_date	2003-10-07
Structure title title	Shiga toxin
Keywords keywords	AB5 toxin, TOXIN; TOXIN
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.

1r4q__assembly_1__model_1

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

Download this curve (.dat)

1r4q__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

1r4q__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	27.87 Å
Rg (electron density)	26.71 Å
Total Rg	27.37 Å
Atom count	4836
Residues	621
Excluded volume	85684 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`1r4q__assembly_1__model_1`	hexameric （6）	Success	4.1.3-1-20251215 (887e7ef)	View Download
2	1	`1r4q__assembly_2__model_1`	hexameric （6）	Success	4.1.3-1-20251215 (887e7ef)	View Download
3	1	`1r4q__assembly_3__model_1`	dodecameric （12）	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	SHT cytotoxin A subunit
Molecular weight formula_weight	32264.4 kDa
EC 编号 ec_number	3.2.2.22
Source method src_method	man
Copy count entity_count	2

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	A,L
Atom count atom_count	9725

KEFTLDFSTAKTYVDSLNVIRSAIGTPLQTISSGGTSLLMIDSGTGDNLFAVDVRGIDPEEGRFNNLRLIVERNNLYVTGFVNRTNNVFYRFADFSHVTFPGTTAVTLSGDSSYTTLQRVAGISRTGMQINRHSLTTSYLDLMSHSGTSLTQSVARAMLRFVTVTAEALRFRQIQRGFRTTLDDLSGRSYVMTAEDVDLTLNWGRLSSVLPDYHGQDSVRVGRISFGSINAILGSVALILNCHHHASRVARMASDEFPSMCPADGRVRGITHNKILWDSSTLGAILMRRTISS

Source Source

Source organism organism	Shigella dysenteriae
NCBI taxonomy ID ncbi_taxonomy_id	622
Host organism host_organism	Escherichia coli

Entity 2 Entity 2 polymer

Description description	Shigella toxin chain B
Molecular weight formula_weight	7698.6 kDa
Source method src_method	man
Copy count entity_count	10

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	B,C,D,E,F,G,H,I,J,K

TPDCVTGKVEYTKYNDDDTFTVKVGDKELFTNRWNLQSLLLSAQITGMTVTIKTNACHNGGGFSEVIFR

Source Source

Source organism organism	Shigella dysenteriae
NCBI taxonomy ID ncbi_taxonomy_id	622
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	46

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6. Fold Classification (SCOP + CATH) 26 domains

SCOP 2.08 (12 domains)

Domain ID domain_id	d1r4qa_
Class class	d — Alpha and beta proteins (a+b)
Fold Fold fold	d.165 — Ribosome inactivating proteins (RIP)
Superfamily Superfamily superfamily	d.165.1 — Ribosome inactivating proteins (RIP)
Family Family family	d.165.1.2 — Shiga toxin, A-chain

Domain ID domain_id	d1r4qb_
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	d1r4qc_
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	d1r4qd_
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	d1r4qe_
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	d1r4qf_
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	d1r4qg_
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	d1r4qh_
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	d1r4qi_
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	d1r4qj_
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	d1r4qk_
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	d1r4ql_
Class class	d — Alpha and beta proteins (a+b)
Fold Fold fold	d.165 — Ribosome inactivating proteins (RIP)
Superfamily Superfamily superfamily	d.165.1 — Ribosome inactivating proteins (RIP)
Family Family family	d.165.1.2 — Shiga toxin, A-chain

CATH v4.4 (14 domains)

Domain ID domain_id	1r4qA01
Class class	3 — Alpha Beta
Architecture architecture	40 — 3-Layer(aba) Sandwich
Topology topology	420 — Ricin (A subunit); domain 1
Homologous superfamily homologous superfamily	10 — Ricin (A subunit), domain 1

Domain ID domain_id	1r4qA02
Class class	4 — Few Secondary Structures
Architecture architecture	10 — Irregular
Topology topology	470 — Ricin (A Subunit), domain 2
Homologous superfamily homologous superfamily	10 — Ricin (A Subunit), domain 2

Domain ID domain_id	1r4qB00
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	50 — OB fold (Dihydrolipoamide Acetyltransferase, E2P)
Homologous superfamily homologous superfamily	70 —

Domain ID domain_id	1r4qC00
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	50 — OB fold (Dihydrolipoamide Acetyltransferase, E2P)
Homologous superfamily homologous superfamily	70 —

Domain ID domain_id	1r4qD00
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	50 — OB fold (Dihydrolipoamide Acetyltransferase, E2P)
Homologous superfamily homologous superfamily	70 —

Domain ID domain_id	1r4qE00
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	50 — OB fold (Dihydrolipoamide Acetyltransferase, E2P)
Homologous superfamily homologous superfamily	70 —

Domain ID domain_id	1r4qF00
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	50 — OB fold (Dihydrolipoamide Acetyltransferase, E2P)
Homologous superfamily homologous superfamily	70 —

Domain ID domain_id	1r4qG00
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	50 — OB fold (Dihydrolipoamide Acetyltransferase, E2P)
Homologous superfamily homologous superfamily	70 —

Domain ID domain_id	1r4qH00
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	50 — OB fold (Dihydrolipoamide Acetyltransferase, E2P)
Homologous superfamily homologous superfamily	70 —

Domain ID domain_id	1r4qI00
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	50 — OB fold (Dihydrolipoamide Acetyltransferase, E2P)
Homologous superfamily homologous superfamily	70 —

Domain ID domain_id	1r4qJ00
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	50 — OB fold (Dihydrolipoamide Acetyltransferase, E2P)
Homologous superfamily homologous superfamily	70 —

Domain ID domain_id	1r4qK00
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	50 — OB fold (Dihydrolipoamide Acetyltransferase, E2P)
Homologous superfamily homologous superfamily	70 —

Domain ID domain_id	1r4qL01
Class class	3 — Alpha Beta
Architecture architecture	40 — 3-Layer(aba) Sandwich
Topology topology	420 — Ricin (A subunit); domain 1
Homologous superfamily homologous superfamily	10 — Ricin (A subunit), domain 1

Domain ID domain_id	1r4qL02
Class class	4 — Few Secondary Structures
Architecture architecture	10 — Irregular
Topology topology	470 — Ricin (A Subunit), domain 2
Homologous superfamily homologous superfamily	10 — Ricin (A Subunit), domain 2

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Unit-cell length a length_a	133.000 Å
Unit-cell length b length_b	147.180 Å
Unit-cell length c length_c	82.850 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	40

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

Resolution resolution	2.500 Å
Low-resolution limit resolution_low	98.600 Å
R factor r_factor	0.2020
R_work r_work	0.1994
R_free r_free	0.2566

Shiga toxin

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

SHT cytotoxin A subunit

State in the Current Structure

Other States of the Same Protein in the Database

Shigella toxin chain B

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

1r4q__assembly_1__model_1

1r4q__assembly_1__model_1 | I(q)

1r4q__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 (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) 26 domains

SCOP 2.08 (12 domains)

CATH v4.4 (14 domains)

7. Citations (1)

Shiga toxin

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

SHT cytotoxin A 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

Shigella toxin chain B

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

1r4q__assembly_1__model_1

1r4q__assembly_1__model_1 | I(q)

1r4q__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 (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) 26 domains

SCOP 2.08 (12 domains)

CATH v4.4 (14 domains)

7. Citations (1)