SAXSdb — 3e8b

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

Potassium channel protein

Bacillus cereus

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein homooligomer	Homooligomer	Protein 4	(4S)-2-METHYL-2,4-PENTANEDIOL × 8 RUBIDIUM ION × 24 water × 4	Consistent with protein count
2	Protein homooligomer	Homooligomer	Protein 4	(4S)-2-METHYL-2,4-PENTANEDIOL × 8 RUBIDIUM ION × 20 water × 4	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	Q81HW2_BACCR
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 1–92； UniProt 19–110 Author chain B； PDBConstruct 1–92； UniProt 19–110

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	3e8b
Deposition date deposition_date	2008-08-19
Structure title title	Crystal Structure of the the open NaK channel- Rb+ complex
Keywords keywords	non-selective cation channel, membrane protein, tetrameric cation channel family, 2-transmembrane helix channels, Ionic channel; 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.

3e8b__assembly_1__model_1

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

Download this curve (.dat)

3e8b__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

3e8b__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	21.40 Å
Rg (electron density)	20.24 Å
Total Rg	21.28 Å
Atom count	2906
Residues	364
Excluded volume	54685 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`3e8b__assembly_1__model_1`	tetrameric （4）	Success	4.1.3-1-20251215 (887e7ef)	View Download
2	1	`3e8b__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 (4)

Entity 1 Entity 1 polymer

Description description	Potassium channel protein
Molecular weight formula_weight	10706.5 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	1603

WKDKEFQVLFVLTILTLISGTIFYSTVEGLRPIDALYFSVVTLTTVGDGNFSPQTDFGKIFTILYIFIGIGLVFGFIHKLAVNVQLPSILSNLVPR

Source Source

Source organism organism	Bacillus cereus
NCBI taxonomy ID ncbi_taxonomy_id	1396
Host organism host_organism	Escherichia coli

Entity 2 Entity 2 non-polymer

Description description	(4S)-2-METHYL-2,4-PENTANEDIOL
Molecular weight formula_weight	118.2 kDa
Source method src_method	syn
Copy count entity_count	4

Entity 3 Entity 3 non-polymer

Description description	RUBIDIUM ION
Molecular weight formula_weight	85.5 kDa
Source method src_method	syn
Copy count entity_count	11

Entity 4 Entity 4 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	94

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6. Fold Classification (SCOP + CATH) 2 domains

CATH v4.4 (2 domains)

Domain ID domain_id	3e8bA00
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	287 — Helix Hairpins
Homologous superfamily homologous superfamily	70 —

Domain ID domain_id	3e8bB00
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	287 — Helix Hairpins
Homologous superfamily homologous superfamily	70 —

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Unit-cell length a length_a	68.134 Å
Unit-cell length b length_b	68.134 Å
Unit-cell length c length_c	89.359 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	I 4
Space-group number int_tables_number	79
Crystal system crystal_system	—

Resolution resolution	1.700 Å
Low-resolution limit resolution_low	27.090 Å
R factor r_factor	—
R_work r_work	0.2200
R_free r_free	0.2290

Crystal Structure of the the open NaK channel- Rb+ complex

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

Potassium channel 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

3e8b__assembly_1__model_1

3e8b__assembly_1__model_1 | I(q)

3e8b__assembly_1__model_1 | P(r) · Pending

4. Crystallography and Experiment 4. Crystallography & Experiment

Unit cell Unit Cell

Symmetry Symmetry

Refinement Refinement

5. Entities and Polymers Entities & Polymers (4)

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 water

6. Fold Classification (SCOP + CATH) 2 domains

CATH v4.4 (2 domains)

7. Citations (1)

Crystal Structure of the the open NaK channel- Rb+ complex

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

Potassium channel 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

3e8b__assembly_1__model_1

3e8b__assembly_1__model_1 | I(q)

3e8b__assembly_1__model_1 | P(r) · Pending

4. Crystallography and Experiment 4. Crystallography & Experiment

Unit cell Unit Cell

Symmetry Symmetry

Refinement Refinement

5. Entities and Polymers Entities & Polymers (4)

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 water

6. Fold Classification (SCOP + CATH) 2 domains

CATH v4.4 (2 domains)

7. Citations (1)