SAXSdb — 1bl8

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

PROTEIN (POTASSIUM CHANNEL PROTEIN)

Streptomyces lividans

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein homooligomer	Homooligomer	Protein 4	POTASSIUM ION × 3 water × 1	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	KCSA_STRLI
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 1–97； UniProt 23–119 Author chain B； PDBConstruct 1–97； UniProt 23–119 Author chain C； PDBConstruct 1–97； UniProt 23–119 Author chain D； PDBConstruct 1–97； UniProt 23–119

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	1bl8
Deposition date deposition_date	1998-07-23
Structure title title	POTASSIUM CHANNEL (KCSA) FROM STREPTOMYCES LIVIDANS
Keywords keywords	POTASSIUM CHANNEL, INTEGRAL MEMBRANE PROTEIN, 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.

1bl8__assembly_1__model_1

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

Download this curve (.dat)

1bl8__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

1bl8__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	21.64 Å
Rg (electron density)	20.58 Å
Total Rg	21.46 Å
Atom count	2823
Residues	388
Excluded volume	51698 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`1bl8__assembly_1__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	PROTEIN (POTASSIUM CHANNEL PROTEIN)
Molecular weight formula_weight	10253.0 kDa
Mutation mutation	L90C
Source method src_method	man
Copy count entity_count	4

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	A,B,C,D
Atom count atom_count	2824

ALHWRAAGAATVLLVIVLLAGSYLAVLAERGAPGAQLITYPRALWWSVETATTVGYGDLYPVTLWGRCVAVVVMVAGITSFGLVTAALATWFVGREQ

Source Source

Source organism organism	Streptomyces lividans
NCBI taxonomy ID ncbi_taxonomy_id	1916
Host organism host_organism	Escherichia coli

Entity 2 Entity 2 non-polymer

Description description	POTASSIUM ION
Molecular weight formula_weight	39.1 kDa
Source method src_method	syn
Copy count entity_count	3

Entity 3 Entity 3 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	1

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6. Fold Classification (SCOP + CATH) 8 domains

SCOP 2.08 (4 domains)

Domain ID domain_id	d1bl8a_
Class class	f — Membrane and cell surface proteins and peptides
Fold Fold fold	f.14 — Gated ion channels
Superfamily Superfamily superfamily	f.14.1 — Voltage-gated ion channels
Family Family family	f.14.1.1 — Voltage-gated potassium channels

Domain ID domain_id	d1bl8b_
Class class	f — Membrane and cell surface proteins and peptides
Fold Fold fold	f.14 — Gated ion channels
Superfamily Superfamily superfamily	f.14.1 — Voltage-gated ion channels
Family Family family	f.14.1.1 — Voltage-gated potassium channels

Domain ID domain_id	d1bl8c_
Class class	f — Membrane and cell surface proteins and peptides
Fold Fold fold	f.14 — Gated ion channels
Superfamily Superfamily superfamily	f.14.1 — Voltage-gated ion channels
Family Family family	f.14.1.1 — Voltage-gated potassium channels

Domain ID domain_id	d1bl8d_
Class class	f — Membrane and cell surface proteins and peptides
Fold Fold fold	f.14 — Gated ion channels
Superfamily Superfamily superfamily	f.14.1 — Voltage-gated ion channels
Family Family family	f.14.1.1 — Voltage-gated potassium channels

CATH v4.4 (4 domains)

Domain ID domain_id	1bl8A00
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	287 — Helix Hairpins
Homologous superfamily homologous superfamily	70 —

Domain ID domain_id	1bl8B00
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	287 — Helix Hairpins
Homologous superfamily homologous superfamily	70 —

Domain ID domain_id	1bl8C00
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	287 — Helix Hairpins
Homologous superfamily homologous superfamily	70 —

Domain ID domain_id	1bl8D00
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	128.780 Å
Unit-cell length b length_b	68.930 Å
Unit-cell length c length_c	112.040 Å
Unit-cell angle α angle_alpha	90.00 °
Unit-cell angle β angle_beta	124.63 °
Unit-cell angle γ angle_gamma	90.00 °
Molecules per unit cell Z z_pdb	16

Space group space_group	C 1 2 1
Space-group number int_tables_number	5
Crystal system crystal_system	—

Resolution resolution	3.200 Å
Low-resolution limit resolution_low	10.000 Å
R factor r_factor	0.2800
R_work r_work	0.2800
R_free r_free	0.2900

POTASSIUM CHANNEL (KCSA) FROM STREPTOMYCES LIVIDANS

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

PROTEIN (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

1bl8__assembly_1__model_1

1bl8__assembly_1__model_1 | I(q)

1bl8__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

6. Fold Classification (SCOP + CATH) 8 domains

SCOP 2.08 (4 domains)

CATH v4.4 (4 domains)

7. Citations (1)

POTASSIUM CHANNEL (KCSA) FROM STREPTOMYCES LIVIDANS

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

PROTEIN (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

1bl8__assembly_1__model_1

1bl8__assembly_1__model_1 | I(q)

1bl8__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

6. Fold Classification (SCOP + CATH) 8 domains

SCOP 2.08 (4 domains)

CATH v4.4 (4 domains)

7. Citations (1)