SAXSdb — 2ntt

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

Staphylococcal enterotoxin K

Staphylococcus aureus subsp. aureus

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein homooligomer	Homooligomer	Protein 2	CHLORIDE ION × 13 1,2-ETHANEDIOL × 10 water × 2	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	Q5HHK0_STAAC
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 1–216； UniProt 24–239 Author chain B； PDBConstruct 1–216； UniProt 24–239

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	2ntt
Deposition date deposition_date	2006-11-08
Structure title title	Crystal Structure of SEK
Keywords keywords	superantigen; T cell receptor, 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.

2ntt__assembly_1__model_1

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

Download this curve (.dat)

2ntt__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

2ntt__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	28.43 Å
Rg (electron density)	27.94 Å
Total Rg	28.56 Å
Atom count	3600
Residues	434
Excluded volume	63773 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`2ntt__assembly_1__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 (4)

Entity 1 Entity 1 polymer

Description description	Staphylococcal enterotoxin K
Molecular weight formula_weight	25079.8 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	4306

QGDIGIDNLRNFYTKKDFVDLKDVKDNDTPIANQLQFSNESYDLISESKDFNKFSNFKGKKLDVFGISYNGQSNTKYIYGGVTATNEYLDKSRNIPINIWINGNHKTISTNKVSTNKKFVTAQEIDVKLRKYLQEEYNIYGHNGTKKGEEYGHKSKFYSGFNIGKVTFHLNNNDTFSYDLFYTGDDGLPKSFLKIYEDNKTVESEKFHLDVDISYKA

Source Source

Source organism organism	Staphylococcus aureus subsp. aureus
NCBI taxonomy ID ncbi_taxonomy_id	93062
Host organism host_organism	Escherichia coli

Entity 2 Entity 2 non-polymer

Description description	CHLORIDE ION
Molecular weight formula_weight	35.5 kDa
Source method src_method	syn
Copy count entity_count	13

Entity 3 Entity 3 non-polymer

Description description	1,2-ETHANEDIOL
Molecular weight formula_weight	62.1 kDa
Source method src_method	syn
Copy count entity_count	10

Entity 4 Entity 4 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	706

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6. Fold Classification (SCOP + CATH) 10 domains

SCOP 2.08 (6 domains)

Domain ID domain_id	d2ntta1
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.40.2.0 — automated matches

Domain ID domain_id	d2ntta2
Class class	d — Alpha and beta proteins (a+b)
Fold Fold fold	d.15 — beta-Grasp (ubiquitin-like)
Superfamily Superfamily superfamily	d.15.6 — Superantigen toxins, C-terminal domain
Family Family family	d.15.6.1 — Superantigen toxins, C-terminal domain

Domain ID domain_id	d2ntta3
Class class	l — Artifacts
Fold Fold fold	l.1 — Tags
Superfamily Superfamily superfamily	l.1.1 — Tags
Family Family family	l.1.1.1 — Tags

Domain ID domain_id	d2nttb1
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.40.2.0 — automated matches

Domain ID domain_id	d2nttb2
Class class	d — Alpha and beta proteins (a+b)
Fold Fold fold	d.15 — beta-Grasp (ubiquitin-like)
Superfamily Superfamily superfamily	d.15.6 — Superantigen toxins, C-terminal domain
Family Family family	d.15.6.1 — Superantigen toxins, C-terminal domain

Domain ID domain_id	d2nttb3
Class class	l — Artifacts
Fold Fold fold	l.1 — Tags
Superfamily Superfamily superfamily	l.1.1 — Tags
Family Family family	l.1.1.1 — Tags

CATH v4.4 (4 domains)

Domain ID domain_id	2nttA01
Class class	3 — Alpha Beta
Architecture architecture	10 — Roll
Topology topology	20 — Ubiquitin-like (UB roll)
Homologous superfamily homologous superfamily	120 —

Domain ID domain_id	2nttA02
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	50 — OB fold (Dihydrolipoamide Acetyltransferase, E2P)
Homologous superfamily homologous superfamily	110 —

Domain ID domain_id	2nttB01
Class class	3 — Alpha Beta
Architecture architecture	10 — Roll
Topology topology	20 — Ubiquitin-like (UB roll)
Homologous superfamily homologous superfamily	120 —

Domain ID domain_id	2nttB02
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	50 — OB fold (Dihydrolipoamide Acetyltransferase, E2P)
Homologous superfamily homologous superfamily	110 —

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Unit-cell length a length_a	53.774 Å
Unit-cell length b length_b	45.790 Å
Unit-cell length c length_c	90.696 Å
Unit-cell angle α angle_alpha	90.00 °
Unit-cell angle β angle_beta	90.02 °
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	1.561 Å
Low-resolution limit resolution_low	34.670 Å
R factor r_factor	0.1650
R_work r_work	0.1630
R_free r_free	0.2020

Crystal Structure of SEK

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

Staphylococcal enterotoxin K

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

2ntt__assembly_1__model_1

2ntt__assembly_1__model_1 | I(q)

2ntt__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 (4)

Entity 1 Entity 1 polymer

Polymer Polymer

Source Source

Entity 2 Entity 2 non-polymer

Entity 3 Entity 3 non-polymer

Entity 4 Entity 4 water

6. Fold Classification (SCOP + CATH) 10 domains

SCOP 2.08 (6 domains)

CATH v4.4 (4 domains)

7. Citations (1)

Crystal Structure of SEK

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

Staphylococcal enterotoxin K

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

2ntt__assembly_1__model_1

2ntt__assembly_1__model_1 | I(q)

2ntt__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 (4)

Entity 1 Entity 1 polymer

Polymer Polymer

Source Source

Entity 2 Entity 2 non-polymer

Entity 3 Entity 3 non-polymer

Entity 4 Entity 4 water

6. Fold Classification (SCOP + CATH) 10 domains

SCOP 2.08 (6 domains)

CATH v4.4 (4 domains)

7. Citations (1)