4I9W | pdb_00004i9w

Human two pore domain K+ channel TRAAK (K2P4.1) - Fab complex structure

External Resource: Annotation

Domain Annotation: SCOP/SCOPe Classification
Domain Annotation: ECOD Classification
Domain Annotation: CATH
IMGT Antibody Annotation
SAbDab Antibody Annotation
Protein Family Annotation
Gene Ontology: Gene Product Annotation
InterPro: Protein Family Classification
Pharos: Disease Associations
Membrane Protein Annotation: OPM
Membrane Protein Annotation: PDBTM
Membrane Protein Annotation: MemProtMD
Membrane Protein Annotation: mpstruc

Domain Annotation: SCOP/SCOPe Classification SCOP-e Database Homepage

Chains	Domain Info	Class	Fold	Superfamily	Family	Domain	Species	Provenance Source (Version)
F [auth G]	d4i9wg_	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	V set domains (antibody variable domain-like)	automated matches	mouse (Mus musculus ) [TaxId: 10090 ],	SCOPe (2.08)
D [auth E]	d4i9we_	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	V set domains (antibody variable domain-like)	automated matches	mouse (Mus musculus ) [TaxId: 10090 ],	SCOPe (2.08)
E [auth F]	d4i9wf2	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	C1 set domains (antibody constant domain-like)	automated matches	mouse (Mus musculus ) [TaxId: 10090 ],	SCOPe (2.08)
E [auth F]	d4i9wf1	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	automated matches	automated matches	mouse (Mus musculus ) [TaxId: 10090 ],	SCOPe (2.08)
C [auth D]	d4i9wd2	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	C1 set domains (antibody constant domain-like)	automated matches	mouse (Mus musculus ) [TaxId: 10090 ],	SCOPe (2.08)
C [auth D]	d4i9wd1	All beta proteins	Immunoglobulin-like beta-sandwich	Immunoglobulin	automated matches	automated matches	mouse (Mus musculus ) [TaxId: 10090 ],	SCOPe (2.08)

Domain Annotation: ECOD Classification ECOD Database Homepage

Chains	Family Name	Domain Identifier	Architecture	Possible Homology	Homology	Topology	Family	Provenance Source (Version)
B	Ribosomal_L12_N	e4i9wB3	A: a/b three-layered sandwiches	X: Fusion glycoprotein F2	H: MoeA-I/Ornithine decarboxylase-C/Reverse ferredoxin-like domain in RNA-polymerase	T: MoeA-I/Ornithine decarboxylase-C/Reverse ferredoxin-like domain in RNA-polymerase	F: Ribosomal_L12_N	ECOD (v294.1)
A	Alba	e4i9wA1	A: a/b three-layered sandwiches	X: Thioredoxin-like	H: ClpP/crotonase	T: ClpP/crotonase	F: Alba	ECOD (v294.1)
F [auth G]	Rrf2	e4i9wG1	A: a/b three-layered sandwiches	X: beta-Grasp	H: HTH	T: winged helix domain	F: Rrf2	ECOD (v294.1)
D [auth E]	Mannitol_dh	e4i9wE1	A: a/b three-layered sandwiches	X: Ribonuclease H-like	H: Ribonuclease H-like	T: Ribonuclease H-like	F: Mannitol_dh	ECOD (v294.1)
E [auth F]	RRM_1	e4i9wF1	A: a/b three-layered sandwiches	X: beta-Grasp	H: HTH	T: winged helix domain	F: RRM_1	ECOD (v294.1)
C [auth D]	Mannitol_dh	e4i9wD1	A: a/b three-layered sandwiches	X: Ribonuclease H-like	H: Ribonuclease H-like	T: Ribonuclease H-like	F: Mannitol_dh	ECOD (v294.1)

Domain Annotation: CATH CATH Database Homepage

Chain	Domain	Class	Architecture	Topology	Homology	Provenance Source (Version)
B	1.10.287.70	Mainly Alpha	Orthogonal Bundle	Helix Hairpins		CATH (4.3.0)
A	1.10.287.70	Mainly Alpha	Orthogonal Bundle	Helix Hairpins		CATH (4.3.0)
F [auth G]	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
D [auth E]	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
E [auth F]	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)
C [auth D]	2.60.40.10	Mainly Beta	Sandwich	Immunoglobulin-like	Immunoglobulins	CATH (4.3.0)

IMGT Antibody Annotation IMGT Database Homepage

Chain	Protein Name	Description	Organism Name	Gene Allele Name(s)	Domain Name(s)	Receptor Type	Receptor Description	Provenance Source
D [auth E], F [auth G]	Antibody Fab Fragment	VH-CH1	Mus musculus (house mouse)	IGHV1-3701, IGHV1-2601, IGHJ201, IGHG102	V-DOMAIN VH, C-DOMAIN CH1	IG	FAB-GAMMA-1_KAPPA	IMGT (202611-0)
C [auth D], E [auth F]	Antibody Fab Fragment	L-KAPPA	Mus musculus (house mouse)	IGKV4-5901, IGKJ501, IGKC01, IGKC02	V-DOMAIN V-KAPPA, C-DOMAIN C-KAPPA	IG	FAB-GAMMA-1_KAPPA	IMGT (202611-0)

SAbDab Antibody Annotation SAbDab Database Homepage

Chain	Chain Class	Chain Subclass	Chain Type	Antigen Name(s)	Provenance Source
D [auth E], F [auth G]	Heavy Chain	IGHV1	-	potassium channel subfamily k member 4	SAbDab (2026-03-27)
C [auth D], E [auth F]	Light Chain	IGKV4	Kappa	potassium channel subfamily k member 4	SAbDab (2026-03-27)

Protein Family Annotation Pfam Database Homepage

Chains	Accession	Name	Description	Comments	Source
A, B	PF07885	Ion channel (Ion_trans_2)	Ion channel	-	Family

Gene Ontology: Gene Product Annotation Gene Ontology Database Homepage

Chains	Polymer	Molecular Function	Biological Process	Cellular Component
A, B	Potassium channel subfamily K member 4	monoatomic cation transmembrane transporter activity potassium ion transmembrane transporter activity monoatomic ion channel activity potassium channel activity monoatomic cation channel activity passive transmembrane transporter activity channel activity monoatomic ion transmembrane transporter activity transporter activity metal ion transmembrane transporter activity transmembrane transporter activity gated channel activity temperature-gated ion channel activity temperature-gated cation channel activity monoatomic cation transmembrane transporter activity potassium ion transmembrane transporter activity monoatomic ion channel activity potassium channel activity monoatomic cation channel activity passive transmembrane transporter activity channel activity monoatomic ion transmembrane transporter activity transporter activity metal ion transmembrane transporter activity transmembrane transporter activity gated channel activity temperature-gated ion channel activity temperature-gated cation channel activity potassium ion leak channel activity narrow pore channel activity leak channel activity mechanosensitive monoatomic cation channel activity mechanosensitive potassium channel activity mechanosensitive monoatomic ion channel activity cation binding ion binding binding metal ion binding small molecule binding identical protein binding protein binding outward rectifier potassium channel activity voltage-gated channel activity voltage-gated monoatomic ion channel activity voltage-gated monoatomic cation channel activity voltage-gated potassium channel activity	transport monoatomic ion transmembrane transport potassium ion transmembrane transport establishment of localization metal ion transport monoatomic cation transmembrane transport transmembrane transport localization monoatomic ion transport potassium ion transport cellular process monoatomic cation transport response to stimulus response to mechanical stimulus transport monoatomic ion transmembrane transport potassium ion transmembrane transport establishment of localization metal ion transport monoatomic cation transmembrane transport transmembrane transport localization monoatomic ion transport potassium ion transport cellular process monoatomic cation transport response to stimulus response to mechanical stimulus response to abiotic stimulus response to external stimulus response to ultrasound cellular response to stimulus response to pH cellular response to pH cellular response to acidic pH response to acidic pH cellular response to abiotic stimulus cellular response to environmental stimulus multicellular organismal process system process sensory perception nervous system process sensory perception of temperature stimulus behavior learning or memory cognition memory response to lipid response to fatty acid response to oxygen-containing compound cellular response to arachidonate cellular response to oxygen-containing compound cellular response to fatty acid cellular response to chemical stimulus response to chemical cellular response to lipid response to arachidonate biological regulation action potential transmission of nerve impulse cell communication neuronal action potential regulation of biological quality regulation of membrane potential detection of external stimulus detection of mechanical stimulus involved in sensory perception of touch sensory perception of touch detection of mechanical stimulus involved in sensory perception sensory perception of mechanical stimulus detection of abiotic stimulus detection of stimulus detection of mechanical stimulus detection of stimulus involved in sensory perception cellular response to mechanical stimulus cellular response to external stimulus sensory perception of pain cellular response to temperature stimulus response to temperature stimulus response to alkaline pH cellular response to alkaline pH	axon cell projection cellular anatomical structure main axon neuron projection node of Ranvier plasma membrane bounded cell projection cell periphery plasma membrane membrane protein-containing complex transmembrane transporter complex potassium channel complex membrane protein complex axon cell projection cellular anatomical structure main axon neuron projection node of Ranvier plasma membrane bounded cell projection cell periphery plasma membrane membrane protein-containing complex transmembrane transporter complex potassium channel complex membrane protein complex cation channel complex transporter complex monoatomic ion channel complex
D [auth E], F [auth G]	ANTIBODY FAB FRAGMENT HEAVY CHAIN	-	-	-
C [auth D], E [auth F]	ANTIBODY FAB FRAGMENT LIGHT CHAIN	-	-	-

InterPro: Protein Family Classification InterPro Database Homepage

Chains	Accession	Name	Type
A, B	IPR008074	Two pore domain potassium channel, TRAAK	Family
A, B	IPR013099	Potassium channel domain	Domain
A, B	IPR003280	Two pore domain potassium channel	Family

Pharos: Disease Associations Pharos Homepage Annotation

Chains	Drug Target	Associated Disease
A, B	Pharos: Q9NYG8	alopecia areata epilepsy leprosy sclerosing cholangitis attention deficit hyperactivity disorder, inattentive type hypertensive disorder primary biliary cholangitis skin basal cell carcinoma Crohn disease inflammatory bowel disease psoriasis vitiligo

Membrane Protein Annotation: OPM OPM Database Homepage

Chains	External Link	Type	Class	Superfamily	Family
A, B	OPM	Transmembrane	Alpha-helical polytopic	Ion channel (VIC) superfamily	Two pore Na+ channels

Membrane Protein Annotation: PDBTM PDBTM Database Homepage

Chains	External Link	Comment
A, B	PDBTM	Annotated as membrane protein by PDBTM

Membrane Protein Annotation: MemProtMD MemProtMD Database Homepage

Chains	External Link	Comment
A, B	MemProtMD	Annotated as membrane protein by MemProtMD

Membrane Protein Annotation: mpstruc mpstruc Database Homepage

Chains	Resource Link	Group	Subgroup	Protein
A, B	mpstruc	TRANSMEMBRANE PROTEINS: ALPHA-HELICAL	Channels: Potassium, Sodium, & Proton Ion-Selective	Two-Pore Domain Potassium Channel K_2P4.1 (TRAAK)

RCSB PDB Core Operations are funded by the U.S. National Science Foundation (DBI-2321666), the US Department of Energy (DE-SC0019749), and the National Cancer Institute, National Institute of Allergy and Infectious Diseases, and National Institute of General Medical Sciences of the National Institutes of Health under grant R01GM157729. RCSB PDB uses resources of the National Energy Research Scientific Computing Center (NERSC), a Department of Energy User Facility.

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