SAXSdb — 2a9h

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

Voltage-gated potassium channel

Streptomyces lividans

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein heterocomplex	Heteromer	Protein 5	charybdotoxin × 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 24–155； UniProt 1–132 Author chain B； PDBConstruct 24–155； UniProt 1–132 Author chain C； PDBConstruct 24–155； UniProt 1–132 Author chain D； PDBConstruct 24–155； UniProt 1–132

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	2a9h
Deposition date deposition_date	2005-07-11
Structure title title	NMR structural studies of a potassium channel / charybdotoxin complex
Keywords keywords	Potassium channel, KcsA, membrane protein, METAL TRANSPORT; METAL TRANSPORT, membrane protein
Experimental Method method	SOLUTION NMR

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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.

2a9h__assembly_1__model_1

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

Download this curve (.dat)

2a9h__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

2a9h__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	22.06 Å
Rg (electron density)	21.02 Å
Total Rg	21.98 Å
Atom count	6381
Residues	424
Excluded volume	57610 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`2a9h__assembly_1__model_1`	pentameric （5）	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 (2)

Entity 1 Entity 1 polymer

Description description	Voltage-gated potassium channel
Molecular weight formula_weight	16717.5 kDa
Mutation mutation	Q58A, T61S, R64D, F103Y, T107F, L110V
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	6381

MSGSHHHHHHSSGIEGRGRLIKHMPPMLSGLLARLVKLLLGRHGSALHWRAAGAATVLLVIVLLAGSYLAVLAERGAPGAALISYPDALWWSVETATTVGYGDLYPVTLWGRCVAVVVMVAGITSYGLVFAAVATWFVGREQERRGHFVRHSEKA

Source Source

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

Entity 2 Entity 2 polymer

Description description	charybdotoxin
Molecular weight formula_weight	4310.0 kDa
Source method src_method	syn
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	E

QFTNVSCTTSKECWSVCQRLHNTSRGKCMNKKCRCYS

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6. Fold Classification (SCOP + CATH) 9 domains

SCOP 2.08 (5 domains)

Domain ID domain_id	d2a9ha1
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	d2a9hb_
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	d2a9hc_
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	d2a9hd_
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	d2a9he1
Class class	g — Small proteins
Fold Fold fold	g.3 — Knottins (small inhibitors, toxins, lectins)
Superfamily Superfamily superfamily	g.3.7 — Scorpion toxin-like
Family Family family	g.3.7.2 — Short-chain scorpion toxins

CATH v4.4 (4 domains)

Domain ID domain_id	2a9hA00
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	287 — Helix Hairpins
Homologous superfamily homologous superfamily	70 —

Domain ID domain_id	2a9hB00
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	287 — Helix Hairpins
Homologous superfamily homologous superfamily	70 —

Domain ID domain_id	2a9hC00
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	287 — Helix Hairpins
Homologous superfamily homologous superfamily	70 —

Domain ID domain_id	2a9hD00
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	287 — Helix Hairpins
Homologous superfamily homologous superfamily	70 —

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NMR structural studies of a potassium channel / charybdotoxin complex

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

Voltage-gated potassium channel

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

2a9h__assembly_1__model_1

2a9h__assembly_1__model_1 | I(q)

2a9h__assembly_1__model_1 | P(r) · Pending

4. Crystallography and Experiment 4. Crystallography & Experiment

5. Entities and Polymers Entities & Polymers (2)

Entity 1 Entity 1 polymer

Polymer Polymer

Source Source

Entity 2 Entity 2 polymer

Polymer Polymer

6. Fold Classification (SCOP + CATH) 9 domains

SCOP 2.08 (5 domains)

CATH v4.4 (4 domains)

7. Citations (1)