SAXSdb — 4dcx

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

Nickel-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	SULFATE ION × 2 ACETATE ION × 17 GLYCEROL × 10 {2,2'-[(1R,2R)-cyclohexane-1,2-diylbis{[(pyridin-2-yl-kappaN)methyl]imino-kappaN}]diacetato-kappaO(2-)}iron × 1 water × 1	Consistent with protein count
2	Protein monomer	Monomer	Protein 1	SULFATE ION × 1 ACETATE ION × 10 GLYCEROL × 8 {2,2'-[(1R,2R)-cyclohexane-1,2-diylbis{[(pyridin-2-yl-kappaN)methyl]imino-kappaN}]diacetato-kappaO(2-)}iron × 1 water × 1	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	NIKA_ECOLI
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 1–502； UniProt 23–524 Author chain B； PDBConstruct 1–502； UniProt 23–524

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	4dcx
Deposition date deposition_date	2012-01-18
Structure title title	X-ray structure of NikA in complex with Fe(1R,2R)-N,N'-Bis(2-pyridylmethyl)-N,N'-dicarboxymethyl-1,2-cyclohexanediamine
Keywords keywords	TRANSPORT PROTEIN, Protein-bound iron complex, 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.

4dcx__assembly_2__model_1

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

Download this curve (.dat)

4dcx__assembly_2__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

4dcx__assembly_2__model_1 | P(r) · Pending

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

Rg（Guinier）	24.97 Å
Rg (electron density)	23.82 Å
Total Rg	24.73 Å
Atom count	4070
Residues	497
Excluded volume	72564 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`4dcx__assembly_1__model_1`	monomeric （1）	Success	4.1.3-1-20251215 (887e7ef)	View Download
2	1	`4dcx__assembly_2__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 (6)

Entity 1 Entity 1 polymer

Description description	Nickel-binding periplasmic protein
Molecular weight formula_weight	56360.7 kDa
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	9194

AAPDEITTAWPVNVGPLNPHLYTPNQMFAQSMVYEPLVKYQADGSVIPWLAKSWTHSEDGKTWTFTLRDDVKFSNGEPFDAEAAAENFRAVLDNRQRHAWLELANQIVDVKALSKTELQITLKSAYYPFLQELALPRPFRFIAPSQFKNHETMNGIKAPIGTGPWILQESKLNQYDVFVRNENYWGEKPAIKKITFNVIPDPTTRAVAFETGDIDLLYGNEGLLPLDTFARFSQNPAYHTQLSQPIETVMLALNTAKAPTNELAVREALNYAVNKKSLIDNALYGTQQVADTLFAPSVPYANLGLKPSQYDPQKAKALLEKAGWTLPAGKDIREKNGQPLRIELSFIGTDALSKSMAEIIQADMRQIGADVSLIGEEESSIYARQRDGRFGMIFHRTWGAPYDPHAFLSSMRVPSHADFQAQQGLADKPLIDKEIGEVLATHDETQRQALYRDILTRLHDEAVYLPISYISMMVVSKPELGNIPYAPIATEIPFEQIKPVKP

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	SULFATE ION
Molecular weight formula_weight	96.1 kDa
Source method src_method	syn
Copy count entity_count	3

Entity 3 Entity 3 non-polymer

Description description	ACETATE ION
Molecular weight formula_weight	59.0 kDa
Source method src_method	syn
Copy count entity_count	27

Entity 4 Entity 4 non-polymer

Description description	GLYCEROL
Molecular weight formula_weight	92.1 kDa
Source method src_method	syn
Copy count entity_count	18

Entity 5 Entity 5 non-polymer

Description description	{2,2'-[(1R,2R)-cyclohexane-1,2-diylbis{[(pyridin-2-yl-kappaN)methyl]imino-kappaN}]diacetato-kappaO(2-)}iron
Molecular weight formula_weight	466.3 kDa
Source method src_method	syn
Copy count entity_count	2

Entity 6 Entity 6 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	858

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6. Fold Classification (SCOP + CATH) 6 domains

SCOP 2.08 (2 domains)

Domain ID domain_id	d4dcxa_
Class class	c — Alpha and beta proteins (a/b)
Fold Fold fold	c.94 — Periplasmic binding protein-like II
Superfamily Superfamily superfamily	c.94.1 — Periplasmic binding protein-like II
Family Family family	c.94.1.1 — Phosphate binding protein-like

Domain ID domain_id	d4dcxb_
Class class	c — Alpha and beta proteins (a/b)
Fold Fold fold	c.94 — Periplasmic binding protein-like II
Superfamily Superfamily superfamily	c.94.1 — Periplasmic binding protein-like II
Family Family family	c.94.1.1 — Phosphate binding protein-like

CATH v4.4 (4 domains)

Domain ID domain_id	4dcxA01
Class class	3 — Alpha Beta
Architecture architecture	40 — 3-Layer(aba) Sandwich
Topology topology	190 — D-Maltodextrin-Binding Protein; domain 2
Homologous superfamily homologous superfamily	10 — Periplasmic binding protein-like II

Domain ID domain_id	4dcxA02
Class class	3 — Alpha Beta
Architecture architecture	10 — Roll
Topology topology	105 — Dipeptide-binding Protein; domain 3
Homologous superfamily homologous superfamily	10 — Dipeptide-binding Protein; Domain 3

Domain ID domain_id	4dcxB01
Class class	3 — Alpha Beta
Architecture architecture	40 — 3-Layer(aba) Sandwich
Topology topology	190 — D-Maltodextrin-Binding Protein; domain 2
Homologous superfamily homologous superfamily	10 — Periplasmic binding protein-like II

Domain ID domain_id	4dcxB02
Class class	3 — Alpha Beta
Architecture architecture	10 — Roll
Topology topology	105 — Dipeptide-binding Protein; domain 3
Homologous superfamily homologous superfamily	10 — Dipeptide-binding Protein; Domain 3

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Unit-cell length a length_a	86.350 Å
Unit-cell length b length_b	95.640 Å
Unit-cell length c length_c	125.190 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	2.000 Å
Low-resolution limit resolution_low	47.820 Å
R factor r_factor	0.1574
R_work r_work	0.1549
R_free r_free	0.2032

X-ray structure of NikA in complex with Fe(1R,2R)-N,N'-Bis(2-pyridylmethyl)-N,N'-dicarboxymethyl-1,2-cyclohexanediamine

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

Nickel-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

4dcx__assembly_2__model_1

4dcx__assembly_2__model_1 | I(q)

4dcx__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 (6)

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 non-polymer

Entity 6 Entity 6 water

6. Fold Classification (SCOP + CATH) 6 domains

SCOP 2.08 (2 domains)

CATH v4.4 (4 domains)

7. Citations (1)

X-ray structure of NikA in complex with Fe(1R,2R)-N,N'-Bis(2-pyridylmethyl)-N,N'-dicarboxymethyl-1,2-cyclohexanediamine

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

Nickel-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

4dcx__assembly_2__model_1

4dcx__assembly_2__model_1 | I(q)

4dcx__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 (6)

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 non-polymer

Entity 6 Entity 6 water

6. Fold Classification (SCOP + CATH) 6 domains

SCOP 2.08 (2 domains)

CATH v4.4 (4 domains)

7. Citations (1)