1kpk

Crystal Structure of the ClC Chloride Channel from E. coli

Method: X-RAY DIFFRACTION

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

putative channel transporter

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	No other associated polymer	Consistent with protein count
2	Protein homooligomer	Homooligomer	Protein 2	No other associated polymer	Consistent with protein count
3	Protein homooligomer	Homooligomer	Protein 2	No other associated polymer	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	CLCA_ECOLI
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 1–473； UniProt 1–473 Author chain B； PDBConstruct 1–473； UniProt 1–473 Author chain C； PDBConstruct 1–473； UniProt 1–473 Author chain D； PDBConstruct 1–473； UniProt 1–473 Author chain E； PDBConstruct 1–473； UniProt 1–473 Author chain F； PDBConstruct 1–473； UniProt 1–473

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	1kpk
Deposition date deposition_date	2001-12-31
Structure title title	Crystal Structure of the ClC Chloride Channel from E. coli
Keywords keywords	helical membrane protein, homodimer, MEMBRANE PROTEIN; MEMBRANE 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.

1kpk__assembly_2__model_1

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

Download this curve (.dat)

1kpk__assembly_2__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

1kpk__assembly_2__model_1 | P(r) · Pending

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

Rg（Guinier）	29.27 Å
Rg (electron density)	28.46 Å
Total Rg	29.25 Å
Atom count	6758
Residues	900
Excluded volume	123600 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`1kpk__assembly_1__model_1`	dimeric （2）	Success	4.1.3-1-20251215 (887e7ef)	View Download
2	1	`1kpk__assembly_2__model_1`	dimeric （2）	Success	4.1.3-1-20251215 (887e7ef)	View Download
3	1	`1kpk__assembly_3__model_1`	dimeric （2）	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 (1)

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6. Fold Classification (SCOP + CATH) 12 domains

SCOP 2.08 (6 domains)

Domain ID domain_id	d1kpka_
Class class	f — Membrane and cell surface proteins and peptides
Fold Fold fold	f.20 — Clc chloride channel
Superfamily Superfamily superfamily	f.20.1 — Clc chloride channel
Family Family family	f.20.1.1 — Clc chloride channel

Domain ID domain_id	d1kpkb_
Class class	f — Membrane and cell surface proteins and peptides
Fold Fold fold	f.20 — Clc chloride channel
Superfamily Superfamily superfamily	f.20.1 — Clc chloride channel
Family Family family	f.20.1.1 — Clc chloride channel

Domain ID domain_id	d1kpkc_
Class class	f — Membrane and cell surface proteins and peptides
Fold Fold fold	f.20 — Clc chloride channel
Superfamily Superfamily superfamily	f.20.1 — Clc chloride channel
Family Family family	f.20.1.1 — Clc chloride channel

Domain ID domain_id	d1kpkd_
Class class	f — Membrane and cell surface proteins and peptides
Fold Fold fold	f.20 — Clc chloride channel
Superfamily Superfamily superfamily	f.20.1 — Clc chloride channel
Family Family family	f.20.1.1 — Clc chloride channel

Domain ID domain_id	d1kpke_
Class class	f — Membrane and cell surface proteins and peptides
Fold Fold fold	f.20 — Clc chloride channel
Superfamily Superfamily superfamily	f.20.1 — Clc chloride channel
Family Family family	f.20.1.1 — Clc chloride channel

Domain ID domain_id	d1kpkf_
Class class	f — Membrane and cell surface proteins and peptides
Fold Fold fold	f.20 — Clc chloride channel
Superfamily Superfamily superfamily	f.20.1 — Clc chloride channel
Family Family family	f.20.1.1 — Clc chloride channel

CATH v4.4 (6 domains)

Domain ID domain_id	1kpkA00
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	3080 — Clc chloride channel
Homologous superfamily homologous superfamily	10 — Clc chloride channel

Domain ID domain_id	1kpkB00
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	3080 — Clc chloride channel
Homologous superfamily homologous superfamily	10 — Clc chloride channel

Domain ID domain_id	1kpkC00
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	3080 — Clc chloride channel
Homologous superfamily homologous superfamily	10 — Clc chloride channel

Domain ID domain_id	1kpkD00
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	3080 — Clc chloride channel
Homologous superfamily homologous superfamily	10 — Clc chloride channel

Domain ID domain_id	1kpkE00
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	3080 — Clc chloride channel
Homologous superfamily homologous superfamily	10 — Clc chloride channel

Domain ID domain_id	1kpkF00
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	3080 — Clc chloride channel
Homologous superfamily homologous superfamily	10 — Clc chloride channel

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Unit-cell length a length_a	105.660 Å
Unit-cell length b length_b	152.525 Å
Unit-cell length c length_c	263.064 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	P 21 21 21
Space-group number int_tables_number	19
Crystal system crystal_system	—

Resolution resolution	3.500 Å
Low-resolution limit resolution_low	20.000 Å
R factor r_factor	0.2900
R_work r_work	0.2900
R_free r_free	0.3010

Description description	putative channel transporter
Molecular weight formula_weight	50390.4 kDa
Source method src_method	man
Copy count entity_count	6

Polymer type type	polypeptide(L)
Chain IDs strand_id	A,B,C,D,E,F
Atom count atom_count	20274

Crystal Structure of the ClC Chloride Channel from E. coli

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

putative channel transporter

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

1kpk__assembly_2__model_1

1kpk__assembly_2__model_1 | I(q)

1kpk__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 (1)

Entity 1 Entity 1 polymer

Polymer Polymer

Source Source

6. Fold Classification (SCOP + CATH) 12 domains

SCOP 2.08 (6 domains)

CATH v4.4 (6 domains)

7. Citations (1)

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

Crystal Structure of the ClC Chloride Channel from E. coli

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

putative channel transporter

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

1kpk__assembly_2__model_1

1kpk__assembly_2__model_1 | I(q)

1kpk__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 (1)

Entity 1 Entity 1 polymer

Polymer Polymer

Source Source

6. Fold Classification (SCOP + CATH) 12 domains

SCOP 2.08 (6 domains)

CATH v4.4 (6 domains)

7. Citations (1)