2dwd

crystal structure of KcsA-FAB-TBA complex in Tl+

Method: X-RAY DIFFRACTION

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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 12	ANTIBODY FAB HEAVY CHAIN × 4 ANTIBODY FAB LIGHT CHAIN × 4 NONAN-1-OL × 4 THALLIUM (I) ION × 16 (2S)-3-HYDROXY-2-(NONANOYLOXY)PROPYL LAURATE × 4 TETRABUTYLAMMONIUM ION × 4 water × 12	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	3
Chains and sequence ranges	Author chain C； PDBConstruct 1–103； UniProt 22–124

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	2dwd
Deposition date deposition_date	2006-08-10
Structure title title	crystal structure of KcsA-FAB-TBA complex in Tl+
Keywords keywords	potassium channel, membrane protein, tetrabutylammonium, K+, KcsA; 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.

2dwd__assembly_1__model_1

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

Download this curve (.dat)

2dwd__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

2dwd__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	46.17 Å
Rg (electron density)	45.39 Å
Total Rg	45.58 Å
Atom count	16437
Residues	2136
Excluded volume	292360 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`2dwd__assembly_1__model_1`	dodecameric （12）	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 (8)

Entity 1 Entity 1 polymer

Description description	ANTIBODY FAB HEAVY CHAIN
Molecular weight formula_weight	23411.2 kDa
Source method src_method	nat
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	A
Atom count atom_count	4190

QVQLQQPGAELVKPGASVKLSCKASGYTFTSDWIHWVKQRPGHGLEWIGEIIPSYGRANYNEKIQKKATLTADKSSSTAFMQLSSLTSEDSAVYYCARERGDGYFAVWGAGTTVTVSSAKTTPPSVYPLAPGSAAQTNSMVTLGCLVKGYFPEPVTVTWNSGSLSSGVHTFPAVLQSDLYTLSSSVTVPSSSWPSETVTCNVAHPASSTKVDKKIVPRD

Entity 2 Entity 2 polymer

Description description	ANTIBODY FAB LIGHT CHAIN
Molecular weight formula_weight	23435.7 kDa
Source method src_method	nat
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	B

DILLTQSPAILSVSPGERVSFSCRASQSIGTDIHWYQQRTNGSPRLLIKYASESISGIPSRFSGSGSGTDFTLSINSVESEDIANYYCQQSNRWPFTFGSGTKLEIKRADAAPTVSIFPPSSEQLTSGGASVVCFLNNFYPKDINVKWKIDGSERQNGVLNSWTDQDSKDSTYSMSSTLTLTKDEYERHNSYTCEATHKTSTSPIVKSFNRN

Entity 3 Entity 3 polymer

Description description	Voltage-gated potassium channel
Molecular weight formula_weight	10978.7 kDa
Mutation mutation	L90C
Source method src_method	man
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	C

SALHWRAAGAATVLLVIVLLAGSYLAVLAERGAPGAQLITYPRALWWSVETATTVGYGDLYPVTLWGRCVAVVVMVAGITSFGLVTAALATWFVGREQERRGH

Source Source

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

Entity 4 Entity 4 non-polymer

Description description	NONAN-1-OL
Molecular weight formula_weight	144.3 kDa
Source method src_method	syn
Copy count entity_count	1

Entity 5 Entity 5 non-polymer

Description description	THALLIUM (I) ION
Molecular weight formula_weight	204.4 kDa
Source method src_method	syn
Copy count entity_count	4

Entity 6 Entity 6 non-polymer

Description description	(2S)-3-HYDROXY-2-(NONANOYLOXY)PROPYL LAURATE
Molecular weight formula_weight	414.6 kDa
Source method src_method	syn
Copy count entity_count	1

Entity 7 Entity 7 non-polymer

Description description	TETRABUTYLAMMONIUM ION
Molecular weight formula_weight	242.5 kDa
Source method src_method	syn
Copy count entity_count	1

Entity 8 Entity 8 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	77

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6. Fold Classification (SCOP + CATH) 11 domains

SCOP 2.08 (6 domains)

Domain ID domain_id	d2dwda1
Class class	b — All beta proteins
Fold Fold fold	b.1 — Immunoglobulin-like beta-sandwich
Superfamily Superfamily superfamily	b.1.1 — Immunoglobulin
Family Family family	b.1.1.1 — V set domains (antibody variable domain-like)

Domain ID domain_id	d2dwda2
Class class	b — All beta proteins
Fold Fold fold	b.1 — Immunoglobulin-like beta-sandwich
Superfamily Superfamily superfamily	b.1.1 — Immunoglobulin
Family Family family	b.1.1.2 — C1 set domains (antibody constant domain-like)

Domain ID domain_id	d2dwda3
Class class	l — Artifacts
Fold Fold fold	l.1 — Tags
Superfamily Superfamily superfamily	l.1.1 — Tags
Family Family family	l.1.1.1 — Tags

Domain ID domain_id	d2dwdb1
Class class	b — All beta proteins
Fold Fold fold	b.1 — Immunoglobulin-like beta-sandwich
Superfamily Superfamily superfamily	b.1.1 — Immunoglobulin
Family Family family	b.1.1.1 — V set domains (antibody variable domain-like)

Domain ID domain_id	d2dwdb2
Class class	b — All beta proteins
Fold Fold fold	b.1 — Immunoglobulin-like beta-sandwich
Superfamily Superfamily superfamily	b.1.1 — Immunoglobulin
Family Family family	b.1.1.2 — C1 set domains (antibody constant domain-like)

Domain ID domain_id	d2dwdc_
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 (5 domains)

Domain ID domain_id	2dwdA01
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	2dwdA02
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	2dwdB01
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	2dwdB02
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	2dwdC00
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	153.180 Å
Unit-cell length b length_b	153.180 Å
Unit-cell length c length_c	75.483 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	8

Space group space_group	I 4
Space-group number int_tables_number	79
Crystal system crystal_system	—

Resolution resolution	2.600 Å
Low-resolution limit resolution_low	48.760 Å
R factor r_factor	0.2410
R_work r_work	0.2190
R_free r_free	0.2630

crystal structure of KcsA-FAB-TBA complex in Tl+

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

2. Structure Basics 2. Structure Basics

3. Official assembly/model SAXS Official SAXS Profiles

2dwd__assembly_1__model_1

2dwd__assembly_1__model_1 | I(q)

2dwd__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 (8)

Entity 1 Entity 1 polymer

Polymer Polymer

Entity 2 Entity 2 polymer

Polymer Polymer

Entity 3 Entity 3 polymer

Polymer Polymer

Source Source

Entity 4 Entity 4 non-polymer

Entity 5 Entity 5 non-polymer

Entity 6 Entity 6 non-polymer

Entity 7 Entity 7 non-polymer

Entity 8 Entity 8 water

6. Fold Classification (SCOP + CATH) 11 domains

SCOP 2.08 (6 domains)

CATH v4.4 (5 domains)

7. Citations (1)

crystal structure of KcsA-FAB-TBA complex in Tl+

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

2dwd__assembly_1__model_1

2dwd__assembly_1__model_1 | I(q)

2dwd__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 (8)

Entity 1 Entity 1 polymer

Polymer Polymer

Entity 2 Entity 2 polymer

Polymer Polymer

Entity 3 Entity 3 polymer

Polymer Polymer

Source Source

Entity 4 Entity 4 non-polymer

Entity 5 Entity 5 non-polymer

Entity 6 Entity 6 non-polymer

Entity 7 Entity 7 non-polymer

Entity 8 Entity 8 water

6. Fold Classification (SCOP + CATH) 11 domains

SCOP 2.08 (6 domains)

CATH v4.4 (5 domains)

7. Citations (1)