SAXSdb — 2o8x

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

Probable RNA polymerase sigma-C factor

Mycobacterium tuberculosis

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein homooligomer	Homooligomer	Protein 3	SULFATE ION × 9 water × 3	Consistent with protein count
2	Protein homooligomer	Homooligomer	Protein 36	SULFATE ION × 108 water × 36	Consistent with protein count
3	Protein homooligomer	Homooligomer	Protein 6	SULFATE ION × 18 water × 6	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	RPSC_MYCTU
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 2–70； UniProt 117–185 Author chain B； PDBConstruct 2–70； UniProt 117–185 Author chain C； PDBConstruct 2–70； UniProt 117–185

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	2o8x
Deposition date deposition_date	2006-12-12
Structure title title	Crystal structure of the "-35 element" promoter recognition domain of Mycobacterium tuberculosis SigC
Keywords keywords	promoter recognition, transcription regulation, helix-turn-helix motif, TRANSCRIPTION; TRANSCRIPTION
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.

2o8x__assembly_2__model_1

Assembly 2 · Model 1 · CRYSOL 4.1.3-1-20251215 (887e7ef)

Download this curve (.dat)

2o8x__assembly_2__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

2o8x__assembly_2__model_1 | P(r) · Pending

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

Rg（Guinier）	47.10 Å
Rg (electron density)	46.02 Å
Total Rg	46.36 Å
Atom count	16692
Residues	2196
Excluded volume	296060 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`2o8x__assembly_1__model_1`	trimeric （3）	Success	4.1.3-1-20251215 (887e7ef)	View Download
2	1	`2o8x__assembly_2__model_1`	36-meric （36）	Success	4.1.3-1-20251215 (887e7ef)	View Download
3	1	`2o8x__assembly_3__model_1`	hexameric （6）	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	Probable RNA polymerase sigma-C factor
Molecular weight formula_weight	7386.4 kDa
Source method src_method	man
Copy count entity_count	3

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	A,B,C
Atom count atom_count	1408

MGFEDLVEVTTMIADLTTDQREALLLTQLLGLSYADAAAVCGCPVGTIRSRVARARDALLADAEPDDLTG

Source Source

Source organism organism	Mycobacterium tuberculosis
NCBI taxonomy ID ncbi_taxonomy_id	83332
Host organism host_organism	Escherichia coli

Entity 2 Entity 2 non-polymer

Description description	SULFATE ION
Molecular weight formula_weight	96.1 kDa
Source method src_method	syn
Copy count entity_count	9

Entity 3 Entity 3 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	17

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6. Fold Classification (SCOP + CATH) 3 domains

CATH v4.4 (3 domains)

Domain ID domain_id	2o8xA00
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	10 — Arc Repressor Mutant, subunit A
Homologous superfamily homologous superfamily	10 — Winged helix-like DNA-binding domain superfamily/Winged helix DNA-binding domain

Domain ID domain_id	2o8xB00
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	10 — Arc Repressor Mutant, subunit A
Homologous superfamily homologous superfamily	10 — Winged helix-like DNA-binding domain superfamily/Winged helix DNA-binding domain

Domain ID domain_id	2o8xC00
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	10 — Arc Repressor Mutant, subunit A
Homologous superfamily homologous superfamily	10 — Winged helix-like DNA-binding domain superfamily/Winged helix DNA-binding domain

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Unit-cell length a length_a	161.330 Å
Unit-cell length b length_b	161.330 Å
Unit-cell length c length_c	161.330 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	144

Space group space_group	F 2 3
Space-group number int_tables_number	196
Crystal system crystal_system	—

Resolution resolution	3.000 Å
Low-resolution limit resolution_low	37.010 Å
R factor r_factor	0.2163
R_work r_work	0.2136
R_free r_free	0.2713

Crystal structure of the "-35 element" promoter recognition domain of Mycobacterium tuberculosis SigC

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

Probable RNA polymerase sigma-C factor

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

2o8x__assembly_2__model_1

2o8x__assembly_2__model_1 | I(q)

2o8x__assembly_2__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 non-polymer

Entity 3 Entity 3 water

6. Fold Classification (SCOP + CATH) 3 domains

CATH v4.4 (3 domains)

7. Citations (1)

Crystal structure of the "-35 element" promoter recognition domain of Mycobacterium tuberculosis SigC

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

Probable RNA polymerase sigma-C factor

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

2o8x__assembly_2__model_1

2o8x__assembly_2__model_1 | I(q)

2o8x__assembly_2__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 non-polymer

Entity 3 Entity 3 water

6. Fold Classification (SCOP + CATH) 3 domains

CATH v4.4 (3 domains)

7. Citations (1)