SAXSdb — 3jsp

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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 (5'-D(TPAPTPAPCPTPGPTPAPTPGPCPGPCPAPTPAPCPAPGPTPA)-3') ; × 2 water × 3	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 A； PDBConstruct 1–202； UniProt 1–202 Author chain B； 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	3jsp
Deposition date deposition_date	2009-09-10
Structure title title	Classic Protein With a New Twist: crystal structure of a LexA repressor 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.

3jsp__assembly_1__model_1

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

Download this curve (.dat)

3jsp__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

3jsp__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	32.63 Å
Rg (electron density)	31.56 Å
Total Rg	32.24 Å
Atom count	3869
Residues	430
Excluded volume	66186 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`3jsp__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 (3)

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	A,B
Atom count atom_count	3880

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 (5'-D(TPAPTPAPCPTPGPTPAPTPGPCPGPCPAPTPAPCPAPGPTPA)-3') ;
Molecular weight formula_weight	6750.4 kDa
Source method src_method	syn
Copy count entity_count	2

Polymer Polymer

Polymer type type	polydeoxyribonucleotide
Chain IDs strand_id	C,D

TATACTGTATGCGCATACAGTA

Entity 3 Entity 3 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	11

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6. Fold Classification (SCOP + CATH) 8 domains

SCOP 2.08 (4 domains)

Domain ID domain_id	d3jspa1
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.4.5.0 — automated matches

Domain ID domain_id	d3jspa2
Class class	b — All beta proteins
Fold Fold fold	b.87 — LexA/Signal peptidase
Superfamily Superfamily superfamily	b.87.1 — LexA/Signal peptidase
Family Family family	b.87.1.1 — LexA-related

Domain ID domain_id	d3jspb1
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.4.5.0 — automated matches

Domain ID domain_id	d3jspb2
Class class	b — All beta proteins
Fold Fold fold	b.87 — LexA/Signal peptidase
Superfamily Superfamily superfamily	b.87.1 — LexA/Signal peptidase
Family Family family	b.87.1.1 — LexA-related

CATH v4.4 (4 domains)

Domain ID domain_id	3jspA01
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	3jspA02
Class class	2 — Mainly Beta
Architecture architecture	10 — Ribbon
Topology topology	109 — Umud Fragment, subunit A
Homologous superfamily homologous superfamily	10 — Umud Fragment, subunit A

Domain ID domain_id	3jspB01
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	3jspB02
Class class	2 — Mainly Beta
Architecture architecture	10 — Ribbon
Topology topology	109 — Umud Fragment, subunit A
Homologous superfamily homologous superfamily	10 — Umud Fragment, subunit A

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Unit-cell length a length_a	94.193 Å
Unit-cell length b length_b	116.869 Å
Unit-cell length c length_c	66.477 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 2
Space-group number int_tables_number	18
Crystal system crystal_system	—

Resolution resolution	2.900 Å
Low-resolution limit resolution_low	43.890 Å
R factor r_factor	0.2670
R_work r_work	0.2660
R_free r_free	0.2870

Classic Protein With a New Twist: crystal structure of a LexA repressor 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

3jsp__assembly_1__model_1

3jsp__assembly_1__model_1 | I(q)

3jsp__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

Entity 3 Entity 3 water

6. Fold Classification (SCOP + CATH) 8 domains

SCOP 2.08 (4 domains)

CATH v4.4 (4 domains)

7. Citations (1)

Classic Protein With a New Twist: crystal structure of a LexA repressor 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

3jsp__assembly_1__model_1

3jsp__assembly_1__model_1 | I(q)

3jsp__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

Entity 3 Entity 3 water

6. Fold Classification (SCOP + CATH) 8 domains

SCOP 2.08 (4 domains)

CATH v4.4 (4 domains)

7. Citations (1)