SAXSdb — 6u18

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

Erythromycin resistance repressor protein

Escherichia coli

State in the Current Structure

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

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	Q9EVJ6_ECOLX
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 1–194； UniProt 1–194 Author chain B； PDBConstruct 1–194； UniProt 1–194

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	6u18
Deposition date deposition_date	2019-08-15
Structure title title	Directed evolution of a biosensor selective for the macrolide antibiotic clarithromycin
Keywords keywords	macrolide, biosensor, DNA-binding, DNA BINDING PROTEIN-ANTIBIOTIC complex; DNA BINDING PROTEIN/ANTIBIOTIC
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.

6u18__assembly_1__model_1

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

Download this curve (.dat)

6u18__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

6u18__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	23.03 Å
Rg (electron density)	21.89 Å
Total Rg	22.74 Å
Atom count	5878
Residues	367
Excluded volume	52688 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`6u18__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	Erythromycin resistance repressor protein
Molecular weight formula_weight	21602.0 kDa
Mutation mutation	R122T, K132N, A151T, H184Q
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	6038

MPRPKLKSDDEVLEAATVVLKRCGPIEFTLSGVAKEVGLSRAALIQRFTNRDTLLVRMMERGVEQVRHYLNAIPIGAGPQGLWEFLQVLVRSMNTRNDFSVNYLISWYELQVPELRTLAIQTNRAVVEGIRNRLPPGAPAAAELLLHSVITGATMQWAVDPDGELADHVLAQIAAILCLMFPEQDDFQLLQAHA

Source Source

Source organism organism	Escherichia coli
NCBI taxonomy ID ncbi_taxonomy_id	562
Host organism host_organism	Escherichia coli BL21(DE3)

Entity 2 Entity 2 non-polymer

Description description	CLARITHROMYCIN
Molecular weight formula_weight	748.0 kDa
Source method src_method	syn
Copy count entity_count	2

Entity 3 Entity 3 non-polymer

Description description	CITRATE ANION
Molecular weight formula_weight	189.1 kDa
Source method src_method	nat
Copy count entity_count	1

Entity 4 Entity 4 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	135

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Unit-cell length a length_a	42.897 Å
Unit-cell length b length_b	53.161 Å
Unit-cell length c length_c	158.815 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	orthorhombic

Resolution resolution	2.000 Å
Low-resolution limit resolution_low	29.140 Å
R factor r_factor	0.2029
R_work r_work	0.2019
R_free r_free	0.2207

Directed evolution of a biosensor selective for the macrolide antibiotic clarithromycin

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

Erythromycin resistance repressor protein

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

6u18__assembly_1__model_1

6u18__assembly_1__model_1 | I(q)

6u18__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 (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

7. Citations (2)

Directed evolution of a biosensor selective for the macrolide antibiotic clarithromycin

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

Erythromycin resistance repressor protein

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

6u18__assembly_1__model_1

6u18__assembly_1__model_1 | I(q)

6u18__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 (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

7. Citations (2)