6r4q

Crystal structure of the periplasmic nickel-binding protein NikA from Escherichia coli in complex with Ru(bpza)CO H2O Cl

Method: X-RAY DIFFRACTION

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

Nickel-binding periplasmic protein

Escherichia coli (strain K12)

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 {[-(BIS-CARBOXYMETHYL-AMINO)-ETHYL]-CARBOXYMETHYL-AMINO}-ACETIC ACID × 1 CHLORIDE ION × 1 GLYCEROL × 11 ACETATE ION × 6 water × 1	Consistent with protein count
2	Protein monomer	Monomer	Protein 1	CHLORIDE ION × 1 GLYCEROL × 8 ACETATE ION × 2 RUTHENIUM ION × 1 bis(pyrzol-1-yl)acetate scorpionate × 1 CARBON MONOXIDE × 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	6r4q
Deposition date deposition_date	2019-03-22
Structure title title	Crystal structure of the periplasmic nickel-binding protein NikA from Escherichia coli in complex with Ru(bpza)CO H2O Cl
Keywords keywords	Artificial metalloenzyme, Ru-based oxidase, styrene oxidation, METAL BINDING PROTEIN; METAL BINDING PROTEIN
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.

6r4q__assembly_2__model_1

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

Download this curve (.dat)

6r4q__assembly_2__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

6r4q__assembly_2__model_1 | P(r) · Pending

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

Rg（Guinier）	24.67 Å
Rg (electron density)	23.64 Å
Total Rg	24.44 Å
Atom count	4000
Residues	497
Excluded volume	71264 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`6r4q__assembly_1__model_1`	monomeric （1）	Success	4.1.3-1-20251215 (887e7ef)	View Download
2	1	`6r4q__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 (10)

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	8848

AAPDEITTAWPVNVGPLNPHLYTPNQMFAQSMVYEPLVKYQADGSVIPWLAKSWTHSEDGKTWTFTLRDDVKFSNGEPFDAEAAAENFRAVLDNRQRHAWLELANQIVDVKALSKTELQITLKSAYYPFLQELALPRPFRFIAPSQFKNHETMNGIKAPIGTGPWILQESKLNQYDVFVRNENYWGEKPAIKKITFNVIPDPTTRAVAFETGDIDLLYGNEGLLPLDTFARFSQNPAYHTQLSQPIETVMLALNTAKAPTNELAVREALNYAVNKKSLIDNALYGTQQVADTLFAPSVPYANLGLKPSQYDPQKAKALLEKAGWTLPAGKDIREKNGQPLRIELSFIGTDALSKSMAEIIQADMRQIGADVSLIGEEESSIYARQRDGRFGMIFHRTWGAPYDPHAFLSSMRVPSHADFQAQQGLADKPLIDKEIGEVLATHDETQRQALYRDILTRLHDEAVYLPISYISMMVVSKPELGNIPYAPIATEIPFEQIKPVKP

Source Source

Source organism organism	Escherichia coli (strain K12)
NCBI taxonomy ID ncbi_taxonomy_id	83333
Host organism host_organism	Escherichia coli BL21(DE3)

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	1

Entity 3 Entity 3 non-polymer

Description description	{[-(BIS-CARBOXYMETHYL-AMINO)-ETHYL]-CARBOXYMETHYL-AMINO}-ACETIC ACID
Molecular weight formula_weight	292.2 kDa
Source method src_method	syn
Copy count entity_count	1

Entity 4 Entity 4 non-polymer

Description description	CHLORIDE ION
Molecular weight formula_weight	35.5 kDa
Source method src_method	syn
Copy count entity_count	2

Entity 5 Entity 5 non-polymer

Description description	GLYCEROL
Molecular weight formula_weight	92.1 kDa
Source method src_method	syn
Copy count entity_count	19

Entity 6 Entity 6 non-polymer

Description description	ACETATE ION
Molecular weight formula_weight	59.0 kDa
Source method src_method	syn
Copy count entity_count	8

Entity 7 Entity 7 non-polymer

Description description	RUTHENIUM ION
Molecular weight formula_weight	101.1 kDa
Source method src_method	syn
Copy count entity_count	1

Entity 8 Entity 8 non-polymer

Description description	bis(pyrzol-1-yl)acetate scorpionate
Molecular weight formula_weight	192.2 kDa
Source method src_method	syn
Copy count entity_count	1

Entity 9 Entity 9 non-polymer

Description description	CARBON MONOXIDE
Molecular weight formula_weight	28.0 kDa
Source method src_method	syn
Copy count entity_count	1

Entity 10 Entity 10 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	738

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6. Fold Classification (SCOP + CATH) 6 domains

SCOP 2.08 (2 domains)

Domain ID domain_id	d6r4qa_
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	d6r4qb_
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	6r4qA01
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	6r4qA02
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	6r4qB01
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	6r4qB02
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	86.629 Å
Unit-cell length b length_b	94.101 Å
Unit-cell length c length_c	124.418 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	1.900 Å
Low-resolution limit resolution_low	44.520 Å
R factor r_factor	0.1804
R_work r_work	0.1777
R_free r_free	0.2319

Crystal structure of the periplasmic nickel-binding protein NikA from Escherichia coli in complex with Ru(bpza)CO H2O Cl

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

6r4q__assembly_2__model_1

6r4q__assembly_2__model_1 | I(q)

6r4q__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 (10)

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 non-polymer

Entity 7 Entity 7 non-polymer

Entity 8 Entity 8 non-polymer

Entity 9 Entity 9 non-polymer

Entity 10 Entity 10 water

6. Fold Classification (SCOP + CATH) 6 domains

SCOP 2.08 (2 domains)

CATH v4.4 (4 domains)

7. Citations (1)

Crystal structure of the periplasmic nickel-binding protein NikA from Escherichia coli in complex with Ru(bpza)CO H2O Cl

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

6r4q__assembly_2__model_1

6r4q__assembly_2__model_1 | I(q)

6r4q__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 (10)

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 non-polymer

Entity 7 Entity 7 non-polymer

Entity 8 Entity 8 non-polymer

Entity 9 Entity 9 non-polymer

Entity 10 Entity 10 water

6. Fold Classification (SCOP + CATH) 6 domains

SCOP 2.08 (2 domains)

CATH v4.4 (4 domains)

7. Citations (1)