SAXSdb — 3ech

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

Multidrug resistance operon repressor

Pseudomonas aeruginosa

UniProt P52003

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein heterocomplex	Heteromer	Protein 3	25-mer fragment of protein ArmR × 1 （Q9HXS2） water × 3	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	MEXR_PSEAE
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 1–142； UniProt 1–142 Author chain B； PDBConstruct 1–142； UniProt 1–142

25-mer fragment of protein ArmR

Pseudomonas aeruginosa

UniProt Q9HXS2

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein heterocomplex	Heteromer	Protein 3	Multidrug resistance operon repressor × 2 （P52003） water × 3	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	Q9HXS2_PSEAE
Isoform	—
PDB entities	2
Chains and sequence ranges	Author chain C； PDBConstruct 1–25； UniProt 29–53

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	3ech
Deposition date deposition_date	2008-08-30
Structure title title	The MarR-family repressor MexR in complex with its antirepressor ArmR
Keywords keywords	winged helix, helix-turn-helix, protein-peptide complex, DNA-binding, Repressor, Transcription, Transcription regulation; Transcription, Transcription 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.

3ech__assembly_1__model_1

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

Download this curve (.dat)

3ech__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

3ech__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	21.95 Å
Rg (electron density)	20.79 Å
Total Rg	21.59 Å
Atom count	2346
Residues	288
Excluded volume	41713 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`3ech__assembly_1__model_1`	trimeric （3）	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	Multidrug resistance operon repressor
Molecular weight formula_weight	16447.0 kDa
Mutation mutation	Q106L, A110L
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	2656

MNYPVNPDLMPALMAVFQHVRTRIQSELDCQRLDLTPPDVHVLKLIDEQRGLNLQDLGRQMCRDKALITRKIRELEGRNLVRRERNPSDQRSFQLFLTDEGLAIHLHAELIMSRVHDELFAPLTPVEQATLVHLLDQCLAAQ

Source Source

Source organism organism	Pseudomonas aeruginosa
NCBI taxonomy ID ncbi_taxonomy_id	287
Host organism host_organism	Escherichia coli

Entity 2 Entity 2 polymer

Description description	25-mer fragment of protein ArmR
Molecular weight formula_weight	3250.6 kDa
Source method src_method	man
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	C

RRDYTEQLRRAARRNAWDLYGEHFY

Source Source

Source organism organism	Pseudomonas aeruginosa
NCBI taxonomy ID ncbi_taxonomy_id	287
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	212

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6. Fold Classification (SCOP + CATH) 4 domains

SCOP 2.08 (2 domains)

Domain ID domain_id	d3echa_
Class class	a — All alpha proteins
Fold Fold fold	a.4 — DNA/RNA-binding 3-helical bundle
Superfamily Superfamily superfamily	a.4.5 — 'Winged helix' DNA-binding domain
Family Family family	a.4.5.28 — MarR-like transcriptional regulators

Domain ID domain_id	d3echb_
Class class	a — All alpha proteins
Fold Fold fold	a.4 — DNA/RNA-binding 3-helical bundle
Superfamily Superfamily superfamily	a.4.5 — 'Winged helix' DNA-binding domain
Family Family family	a.4.5.28 — MarR-like transcriptional regulators

CATH v4.4 (2 domains)

Domain ID domain_id	3echA01
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	3echB01
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	52.201 Å
Unit-cell length b length_b	57.151 Å
Unit-cell length c length_c	91.931 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	8

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

Resolution resolution	1.802 Å
Low-resolution limit resolution_low	48.560 Å
R factor r_factor	0.1782
R_work r_work	0.1756
R_free r_free	0.2291

The MarR-family repressor MexR in complex with its antirepressor ArmR

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

Multidrug resistance operon repressor

State in the Current Structure

Other States of the Same Protein in the Database

25-mer fragment of protein ArmR

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

3ech__assembly_1__model_1

3ech__assembly_1__model_1 | I(q)

3ech__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) 4 domains

SCOP 2.08 (2 domains)

CATH v4.4 (2 domains)

7. Citations (1)

The MarR-family repressor MexR in complex with its antirepressor ArmR

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

Multidrug resistance operon 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

25-mer fragment of protein ArmR

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

3ech__assembly_1__model_1

3ech__assembly_1__model_1 | I(q)

3ech__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) 4 domains

SCOP 2.08 (2 domains)

CATH v4.4 (2 domains)

7. Citations (1)