SAXSdb — 6d42

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

Intermediate conductance calcium-activated potassium channel protein 4

Homo sapiens

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein homooligomer	Homooligomer	Protein 4	COPPER (II) ION × 4 water × 4	Consistent with protein count
2	Protein homooligomer	Homooligomer	Protein 4	COPPER (II) ION × 4 water × 4	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	KCNN4_HUMAN
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 3–42； UniProt 376–415 Author chain B； PDBConstruct 3–42； UniProt 376–415

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	6d42
Deposition date deposition_date	2018-04-17
Structure title title	Crystal structure of the KCa3.1 C-terminal four-helix bundle (with copper)
Keywords keywords	Four-helix bundle, copper, 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.

6d42__assembly_1__model_1

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

Download this curve (.dat)

6d42__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

6d42__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	18.96 Å
Rg (electron density)	19.01 Å
Total Rg	19.86 Å
Atom count	1189
Residues	152
Excluded volume	21422 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`6d42__assembly_1__model_1`	tetrameric （4）	Success	4.1.3-1-20251215 (887e7ef)	View Download
2	1	`6d42__assembly_2__model_1`	tetrameric （4）	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 (3)

Entity 1 Entity 1 polymer

Description description	Intermediate conductance calcium-activated potassium channel protein 4
Molecular weight formula_weight	4567.0 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	642

GSMILYDLQQNLSSSHRALEKQIDTLAGKLDALTELLSTALG

Source Source

Source organism organism	Homo sapiens
Common name common_name	Human
NCBI taxonomy ID ncbi_taxonomy_id	9606
Host organism host_organism	Escherichia coli

Entity 2 Entity 2 non-polymer

Description description	COPPER (II) ION
Molecular weight formula_weight	63.5 kDa
Source method src_method	syn
Copy count entity_count	2

Entity 3 Entity 3 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	42

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Unit-cell length a length_a	37.590 Å
Unit-cell length b length_b	37.590 Å
Unit-cell length c length_c	116.946 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 4 21 2
Space-group number int_tables_number	90
Crystal system crystal_system	tetragonal

Resolution resolution	1.750 Å
Low-resolution limit resolution_low	27.059 Å
R factor r_factor	0.2595
R_work r_work	0.2521
R_free r_free	0.3226

Crystal structure of the KCa3.1 C-terminal four-helix bundle (with copper)

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

Intermediate conductance calcium-activated potassium channel protein 4

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

6d42__assembly_1__model_1

6d42__assembly_1__model_1 | I(q)

6d42__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 (3)

Entity 1 Entity 1 polymer

Polymer Polymer

Source Source

Entity 2 Entity 2 non-polymer

Entity 3 Entity 3 water

7. Citations (1)

Crystal structure of the KCa3.1 C-terminal four-helix bundle (with copper)

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

Intermediate conductance calcium-activated potassium channel protein 4

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

6d42__assembly_1__model_1

6d42__assembly_1__model_1 | I(q)

6d42__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 (3)

Entity 1 Entity 1 polymer

Polymer Polymer

Source Source

Entity 2 Entity 2 non-polymer

Entity 3 Entity 3 water

7. Citations (1)