SAXSdb — 3k3r

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

LexA repressor

Escherichia coli K-12

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein–DNA	Homooligomer	Protein 2 DNA 2	DNA (28-MER) × 2	Consistent with all polymers

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	LEXA_ECOLI
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain E； PDBConstruct 1–202； UniProt 1–202 Author chain F； PDBConstruct 1–202； UniProt 1–202

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	3k3r
Deposition date deposition_date	2009-10-04
Structure title title	Unrefined crystal structure of a LexA-DNA complex
Keywords keywords	;protein-DNA complex, winged helix-turn-helix, double helix, repressor, LexA, SOS system, Autocatalytic cleavage, DNA damage, DNA repair, DNA replication, DNA-binding, Hydrolase, SOS response, Transcription, Transcription regulation, HYDROLASE-DNA COMPLEX ;; HYDROLASE/DNA
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.

3k3r__assembly_1__model_1

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

Download this curve (.dat)

3k3r__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

3k3r__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	31.33 Å
Rg (electron density)	28.94 Å
Total Rg	29.34 Å
Atom count	56
Residues	56
Excluded volume	47580 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`3k3r__assembly_1__model_1`	tetrameric （4）	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)

Entity 1 Entity 1 polymer

Description description	LexA repressor
Molecular weight formula_weight	22330.6 kDa
EC 编号 ec_number	3.4.21.88
Mutation mutation	K156A
Source method src_method	man
Copy count entity_count	2

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	E,F
Atom count atom_count	403

MKALTARQQEVFDLIRDHISQTGMPPTRAEIAQRLGFRSPNAAEEHLKALARKGVIEIVSGASRGIRLLQEEEEGLPLVGRVAAGEPLLAQQHIEGHYQVDPSLFKPNADFLLRVSGMSMKDIGIMDGDLLAVHKTQDVRNGQVVVARIDDEVTVARLKKQGNKVELLPENSEFKPIVVDLRQQSFTIEGLAVGVIRNGDWL

Source Source

Source organism organism	Escherichia coli K-12
NCBI taxonomy ID ncbi_taxonomy_id	83333
Host organism host_organism	Escherichia coli

Entity 2 Entity 2 polymer

Description description	DNA (28-MER)
Molecular weight formula_weight	8931.8 kDa
Source method src_method	syn
Copy count entity_count	2

Polymer Polymer

Polymer type type	polydeoxyribonucleotide
Chain IDs strand_id	A,B

GTTGATACTGTATGATCATACAGTATCAA

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Unit-cell length a length_a	45.357 Å
Unit-cell length b length_b	120.393 Å
Unit-cell length c length_c	149.814 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	3.200 Å
Low-resolution limit resolution_low	50.000 Å
R factor r_factor	—
R_work r_work	—
R_free r_free	—

Unrefined crystal structure of a LexA-DNA complex

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

LexA 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

3k3r__assembly_1__model_1

3k3r__assembly_1__model_1 | I(q)

3k3r__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 polymer

Polymer Polymer

7. Citations (1)

Unrefined crystal structure of a LexA-DNA complex

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

LexA 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

3k3r__assembly_1__model_1

3k3r__assembly_1__model_1 | I(q)

3k3r__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 polymer

Polymer Polymer

7. Citations (1)