SAXSdb — 1irq

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

omega transcriptional repressor

Streptococcus pyogenes

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein homooligomer	Homooligomer	Protein 2	water × 2	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	Q57468_STRPY
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 1–71； UniProt 1–71 Author chain B； PDBConstruct 1–71； UniProt 1–71

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	1irq
Deposition date deposition_date	2001-10-11
Structure title title	Crystal structure of omega transcriptional repressor at 1.5A resolution
Keywords keywords	transcriptional repressor, ribbon-helix-helix, 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.

1irq__assembly_1__model_1

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

Download this curve (.dat)

1irq__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

1irq__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	14.50 Å
Rg (electron density)	13.19 Å
Total Rg	14.48 Å
Atom count	786
Residues	97
Excluded volume	14133 Å³
Maximum q	0.500 Å⁻¹

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

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6. Fold Classification (SCOP + CATH) 4 domains

SCOP 2.08 (2 domains)

Domain ID domain_id	d1irqa_
Class class	a — All alpha proteins
Fold Fold fold	a.43 — Ribbon-helix-helix
Superfamily Superfamily superfamily	a.43.1 — Ribbon-helix-helix
Family Family family	a.43.1.4 — Omega transcriptional repressor

Domain ID domain_id	d1irqb_
Class class	a — All alpha proteins
Fold Fold fold	a.43 — Ribbon-helix-helix
Superfamily Superfamily superfamily	a.43.1 — Ribbon-helix-helix
Family Family family	a.43.1.4 — Omega transcriptional repressor

CATH v4.4 (2 domains)

Domain ID domain_id	1irqA00
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	1220 — Arc Repressor Mutant
Homologous superfamily homologous superfamily	10 — Met repressor-like

Domain ID domain_id	1irqB00
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	1220 — Arc Repressor Mutant
Homologous superfamily homologous superfamily	10 — Met repressor-like

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Unit-cell length a length_a	46.100 Å
Unit-cell length b length_b	46.100 Å
Unit-cell length c length_c	88.300 Å
Unit-cell angle α angle_alpha	90.00 °
Unit-cell angle β angle_beta	90.00 °
Unit-cell angle γ angle_gamma	120.00 °
Molecules per unit cell Z z_pdb	12

Space group space_group	P 61
Space-group number int_tables_number	169
Crystal system crystal_system	—

Resolution resolution	1.500 Å
Low-resolution limit resolution_low	29.600 Å
R factor r_factor	0.2110
R_work r_work	0.2110
R_free r_free	0.2320

Description description	omega transcriptional repressor
Molecular weight formula_weight	8004.4 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	968

Crystal structure of omega transcriptional repressor at 1.5A resolution

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

omega transcriptional repressor

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

1irq__assembly_1__model_1

1irq__assembly_1__model_1 | I(q)

1irq__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) 4 domains

SCOP 2.08 (2 domains)

CATH v4.4 (2 domains)

7. Citations (1)

Source organism organism	Streptococcus pyogenes
NCBI taxonomy ID ncbi_taxonomy_id	1314
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	125

Crystal structure of omega transcriptional repressor at 1.5A resolution

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

omega transcriptional repressor

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

1irq__assembly_1__model_1

1irq__assembly_1__model_1 | I(q)

1irq__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) 4 domains

SCOP 2.08 (2 domains)

CATH v4.4 (2 domains)

7. Citations (1)