SAXSdb — 3tlk

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

Ferrienterobactin-binding periplasmic protein

Escherichia coli

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein monomer	Monomer	Protein 1	FE (III) ION × 1 N,N',N''-[(3S,7S,11S)-2,6,10-trioxo-1,5,9-trioxacyclododecane-3,7,11-triyl]tris(2,3-dihydroxybenzamide) × 2 1,4-DIETHYLENE DIOXIDE × 1 water × 1	Consistent with protein count
2	Protein monomer	Monomer	Protein 1	FE (III) ION × 2 N,N',N''-[(3S,7S,11S)-2,6,10-trioxo-1,5,9-trioxacyclododecane-3,7,11-triyl]tris(2,3-dihydroxybenzamide) × 1 1,4-DIETHYLENE DIOXIDE × 1 water × 1	Consistent with protein count
3	Protein monomer	Monomer	Protein 1	FE (III) ION × 1 N,N',N''-[(3S,7S,11S)-2,6,10-trioxo-1,5,9-trioxacyclododecane-3,7,11-triyl]tris(2,3-dihydroxybenzamide) × 1 1,4-DIETHYLENE DIOXIDE × 1 water × 1	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	FEPB_ECOLI
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 1–318； UniProt 1–318 Author chain B； PDBConstruct 1–318； UniProt 1–318 Author chain C； PDBConstruct 1–318； UniProt 1–318

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	3tlk
Deposition date deposition_date	2011-08-30
Structure title title	Crystal structure of holo FepB
Keywords keywords	Ferric-enterobactin, trimer, siderophore transport, Periplasmic space, METAL TRANSPORT; METAL TRANSPORT
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.

3tlk__assembly_2__model_1

Assembly 2 · Model 1 · CRYSOL 4.1.3-1-20251215 (887e7ef)

Download this curve (.dat)

3tlk__assembly_2__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

3tlk__assembly_2__model_1 | P(r) · Pending

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

Rg（Guinier）	20.22 Å
Rg (electron density)	19.29 Å
Total Rg	20.19 Å
Atom count	2277
Residues	291
Excluded volume	40475 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`3tlk__assembly_1__model_1`	monomeric （1）	Success	4.1.3-1-20251215 (887e7ef)	View Download
2	1	`3tlk__assembly_2__model_1`	monomeric （1）	Success	4.1.3-1-20251215 (887e7ef)	View Download
3	1	`3tlk__assembly_3__model_1`	monomeric （1）	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 (5)

Entity 1 Entity 1 polymer

Description description	Ferrienterobactin-binding periplasmic protein
Molecular weight formula_weight	35385.0 kDa
Source method src_method	man
Copy count entity_count	3

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	A,B,C
Atom count atom_count	7572

MRLAPLYRNALLLTGLLLSGIAAVQAADWPRQITDSRGTHTLESQPQRIVSTSVTLTGSLLAIDAPVIASGATTPNNRVADDQGFLRQWSKVAKERKLQRLYIGEPSAEAVAAQMPDLILISATGGDSALALYDQLSTIAPTLIINYDDKSWQSLLTQLGEITGHEKQAAERIAQFDKQLAAAKEQIKLPPQPVTAIVYTAAAHSANLWTPESAQGQMLEQLGFTLAKLPAGLNASQSQGKRHDIIQLGGENLAAGLNGESLFLFAGDQKDADAIYANPLLAHLPAVQNKQVYALGTETFRLDYYSAMQVLDRLKALFLEHHHHHH

Source Source

Source organism organism	Escherichia coli
NCBI taxonomy ID ncbi_taxonomy_id	83333
Host organism host_organism	Escherichia coli

Entity 2 Entity 2 non-polymer

Description description	FE (III) ION
Molecular weight formula_weight	55.8 kDa
Source method src_method	syn
Copy count entity_count	4

Entity 3 Entity 3 non-polymer

Description description	N,N',N''-[(3S,7S,11S)-2,6,10-trioxo-1,5,9-trioxacyclododecane-3,7,11-triyl]tris(2,3-dihydroxybenzamide)
Molecular weight formula_weight	669.5 kDa
Source method src_method	syn
Copy count entity_count	4

Entity 4 Entity 4 non-polymer

Description description	1,4-DIETHYLENE DIOXIDE
Molecular weight formula_weight	88.1 kDa
Source method src_method	syn
Copy count entity_count	3

Entity 5 Entity 5 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	616

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6. Fold Classification (SCOP + CATH) 11 domains

SCOP 2.08 (5 domains)

Domain ID domain_id	d3tlka1
Class class	c — Alpha and beta proteins (a/b)
Fold Fold fold	c.92 — Chelatase-like
Superfamily Superfamily superfamily	c.92.2 — 'Helical backbone' metal receptor
Family Family family	c.92.2.0 — automated matches

Domain ID domain_id	d3tlka2
Class class	l — Artifacts
Fold Fold fold	l.1 — Tags
Superfamily Superfamily superfamily	l.1.1 — Tags
Family Family family	l.1.1.1 — Tags

Domain ID domain_id	d3tlkb_
Class class	c — Alpha and beta proteins (a/b)
Fold Fold fold	c.92 — Chelatase-like
Superfamily Superfamily superfamily	c.92.2 — 'Helical backbone' metal receptor
Family Family family	c.92.2.0 — automated matches

Domain ID domain_id	d3tlkc1
Class class	c — Alpha and beta proteins (a/b)
Fold Fold fold	c.92 — Chelatase-like
Superfamily Superfamily superfamily	c.92.2 — 'Helical backbone' metal receptor
Family Family family	c.92.2.0 — automated matches

Domain ID domain_id	d3tlkc2
Class class	l — Artifacts
Fold Fold fold	l.1 — Tags
Superfamily Superfamily superfamily	l.1.1 — Tags
Family Family family	l.1.1.1 — Tags

CATH v4.4 (6 domains)

Domain ID domain_id	3tlkA01
Class class	3 — Alpha Beta
Architecture architecture	40 — 3-Layer(aba) Sandwich
Topology topology	50 — Rossmann fold
Homologous superfamily homologous superfamily	1980 — Nitrogenase molybdenum iron protein domain

Domain ID domain_id	3tlkA02
Class class	3 — Alpha Beta
Architecture architecture	40 — 3-Layer(aba) Sandwich
Topology topology	50 — Rossmann fold
Homologous superfamily homologous superfamily	1980 — Nitrogenase molybdenum iron protein domain

Domain ID domain_id	3tlkB01
Class class	3 — Alpha Beta
Architecture architecture	40 — 3-Layer(aba) Sandwich
Topology topology	50 — Rossmann fold
Homologous superfamily homologous superfamily	1980 — Nitrogenase molybdenum iron protein domain

Domain ID domain_id	3tlkB02
Class class	3 — Alpha Beta
Architecture architecture	40 — 3-Layer(aba) Sandwich
Topology topology	50 — Rossmann fold
Homologous superfamily homologous superfamily	1980 — Nitrogenase molybdenum iron protein domain

Domain ID domain_id	3tlkC01
Class class	3 — Alpha Beta
Architecture architecture	40 — 3-Layer(aba) Sandwich
Topology topology	50 — Rossmann fold
Homologous superfamily homologous superfamily	1980 — Nitrogenase molybdenum iron protein domain

Domain ID domain_id	3tlkC02
Class class	3 — Alpha Beta
Architecture architecture	40 — 3-Layer(aba) Sandwich
Topology topology	50 — Rossmann fold
Homologous superfamily homologous superfamily	1980 — Nitrogenase molybdenum iron protein domain

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Unit-cell length a length_a	74.024 Å
Unit-cell length b length_b	131.591 Å
Unit-cell length c length_c	196.113 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	24

Space group space_group	C 2 2 21
Space-group number int_tables_number	20
Crystal system crystal_system	—

Resolution resolution	1.853 Å
Low-resolution limit resolution_low	39.314 Å
R factor r_factor	0.1802
R_work r_work	0.1793
R_free r_free	0.2168

Crystal structure of holo FepB

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

Ferrienterobactin-binding periplasmic 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

3tlk__assembly_2__model_1

3tlk__assembly_2__model_1 | I(q)

3tlk__assembly_2__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 (5)

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 non-polymer

Entity 5 Entity 5 water

6. Fold Classification (SCOP + CATH) 11 domains

SCOP 2.08 (5 domains)

CATH v4.4 (6 domains)

7. Citations (1)

Crystal structure of holo FepB

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

Ferrienterobactin-binding periplasmic 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

3tlk__assembly_2__model_1

3tlk__assembly_2__model_1 | I(q)

3tlk__assembly_2__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 (5)

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 non-polymer

Entity 5 Entity 5 water

6. Fold Classification (SCOP + CATH) 11 domains

SCOP 2.08 (5 domains)

CATH v4.4 (6 domains)

7. Citations (1)