SAXSdb — 2paf

▼

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

Lactose operon repressor

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	2-nitrophenyl beta-D-fucopyranoside × 2	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	LACI_ECOLI
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 1–269； UniProt 62–330 Author chain B； PDBConstruct 1–269； UniProt 62–330

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.

▼

2. Structure Basics 2. Structure Basics

Entry ID entry_id	2paf
Deposition date deposition_date	2007-03-27
Structure title title	Crystal Structure of the Lactose Repressor bound to anti-inducer ONPF in induced state
Keywords keywords	Lac repressor, allosteric effectors, gene regulation, TRANSCRIPTION; TRANSCRIPTION
Experimental Method method	X-RAY DIFFRACTION

▼

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.

2paf__assembly_1__model_1

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

Download this curve (.dat)

2paf__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

2paf__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	24.45 Å
Rg (electron density)	23.48 Å
Total Rg	24.33 Å
Atom count	4068
Residues	538
Excluded volume	72669 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`2paf__assembly_1__model_1`	dimeric （2）	Success	4.1.3-1-20251215 (887e7ef)	View Download

▶

4. Crystallography and Experiment 4. Crystallography & Experiment

▶

5. Entities and Polymers Entities & Polymers (2)

▼

6. Fold Classification (SCOP + CATH) 6 domains

SCOP 2.08 (2 domains)

Domain ID domain_id	d2pafa1
Class class	c — Alpha and beta proteins (a/b)
Fold Fold fold	c.93 — Periplasmic binding protein-like I
Superfamily Superfamily superfamily	c.93.1 — Periplasmic binding protein-like I
Family Family family	c.93.1.1 — L-arabinose binding protein-like

Domain ID domain_id	d2pafb1
Class class	c — Alpha and beta proteins (a/b)
Fold Fold fold	c.93 — Periplasmic binding protein-like I
Superfamily Superfamily superfamily	c.93.1 — Periplasmic binding protein-like I
Family Family family	c.93.1.1 — L-arabinose binding protein-like

CATH v4.4 (4 domains)

Domain ID domain_id	2pafA01
Class class	3 — Alpha Beta
Architecture architecture	40 — 3-Layer(aba) Sandwich
Topology topology	50 — Rossmann fold
Homologous superfamily homologous superfamily	2300 — Response regulator

Domain ID domain_id	2pafA02
Class class	3 — Alpha Beta
Architecture architecture	40 — 3-Layer(aba) Sandwich
Topology topology	50 — Rossmann fold
Homologous superfamily homologous superfamily	2300 — Response regulator

Domain ID domain_id	2pafB01
Class class	3 — Alpha Beta
Architecture architecture	40 — 3-Layer(aba) Sandwich
Topology topology	50 — Rossmann fold
Homologous superfamily homologous superfamily	2300 — Response regulator

Domain ID domain_id	2pafB02
Class class	3 — Alpha Beta
Architecture architecture	40 — 3-Layer(aba) Sandwich
Topology topology	50 — Rossmann fold
Homologous superfamily homologous superfamily	2300 — Response regulator

▶

Unit-cell length a length_a	77.541 Å
Unit-cell length b length_b	77.541 Å
Unit-cell length c length_c	212.456 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	16

Space group space_group	P 41 21 2
Space-group number int_tables_number	92
Crystal system crystal_system	—

Resolution resolution	3.500 Å
Low-resolution limit resolution_low	19.810 Å
R factor r_factor	0.1986
R_work r_work	0.1954
R_free r_free	0.2652

Description description	Lactose operon repressor
Molecular weight formula_weight	28756.9 kDa
Source method src_method	man
Copy count entity_count	2

Polymer type type	polypeptide(L)
Chain IDs strand_id	A,B
Atom count atom_count	4068

Crystal Structure of the Lactose Repressor bound to anti-inducer ONPF in induced state

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

Lactose operon 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

2paf__assembly_1__model_1

2paf__assembly_1__model_1 | I(q)

2paf__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 non-polymer

6. Fold Classification (SCOP + CATH) 6 domains

SCOP 2.08 (2 domains)

CATH v4.4 (4 domains)

7. Citations (1)

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

Description description	2-nitrophenyl beta-D-fucopyranoside
Molecular weight formula_weight	285.2 kDa
Source method src_method	syn
Copy count entity_count	2

Crystal Structure of the Lactose Repressor bound to anti-inducer ONPF in induced state

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

Lactose 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

2. Structure Basics 2. Structure Basics

3. Official assembly/model SAXS Official SAXS Profiles

2paf__assembly_1__model_1

2paf__assembly_1__model_1 | I(q)

2paf__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 non-polymer

6. Fold Classification (SCOP + CATH) 6 domains

SCOP 2.08 (2 domains)

CATH v4.4 (4 domains)

7. Citations (1)