4I9W: Potassium channel subfamily K member 4

Human two pore domain K+ channel TRAAK (K2P4.1) - Fab complex structure. Determined by X-ray diffraction at 2.75 Å resolution. Released 23 Jan 2013.

Method: X-ray diffraction
Resolution: 2.75 Å
Organisms: Homo sapiens, Mus musculus
Chains: 6
Atoms: 10,544
Mol. weight: 160.47 kDa
Ligands: CA
Released: 23 Jan 2013

Explore 4I9W in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

4I9W contains 51 α-helices and 87 β-strands across 6 chains. Residue ranges use author residue numbering, as in the PDB file, from PDBe. To see them in 3D, choose the Cartoon representation with Secondary structure coloring: helices, sheets and coils get different colors.

Chain A: 11 helices, 2 β-strands

Element	Residues	Length	Sheet
α-helix	29-54	26
α-helix	55-57	3
α-helix	60-75	16
α-helix	81-96	16
α-helix	116-127	12
α-helix	140-185	46
α-helix	190-205	16
α-helix	206-211	6
α-helix	212-221	10
α-helix	225-236	12
β-strand	251	1	1
β-strand	254	1	1
α-helix	257-285	29

Chain B: 9 helices, 0 β-strands

Element	Residues	Length
α-helix	29-75	47
α-helix	81-96	16
α-helix	116-127	12
α-helix	140-185	46
α-helix	190-205	16
α-helix	206-211	6
α-helix	212-221	10
α-helix	225-236	12
α-helix	257-283	27

Chain D: 8 helices, 21 β-strands

Element	Residues	Length	Sheet
β-strand	4-5	2	2
β-strand	10-13	4	3
β-strand	19-25	7	2
β-strand	33-37	5	3
β-strand	44-48	5	3
β-strand	52-53	2	3
α-helix	54	1
β-strand	61-66	6	2
β-strand	69-74	6	2
α-helix	79-81	3
β-strand	83-89	7	3
α-helix	95	1
β-strand	96-97	2	3
β-strand	101-105	5	3
β-strand	110	1	4
α-helix	111-112	2
β-strand	113-117	5	5
α-helix	118-120	3
α-helix	121-125	5
β-strand	128-138	11	5
β-strand	139	1	4
β-strand	144-149	6	6
β-strand	152-154	3	6
β-strand	158-162	5	5
α-helix	163-166	4
β-strand	172-181	10	5
α-helix	182-187	6
β-strand	190-196	7	6
β-strand	204-209	6	6

Chain E: 7 helices, 21 β-strands

Element	Residues	Length	Sheet
β-strand	3-6	4	7
β-strand	10-12	3	8
β-strand	18-25	8	7
α-helix	29-31	3
β-strand	34-39	6	8
β-strand	45-51	7	8
β-strand	58-60	3	8
α-helix	62-64	3
β-strand	68-73	6	7
β-strand	78-83	6	7
α-helix	88-90	3
β-strand	92-98	7	8
β-strand	105-106	2	8
β-strand	110-114	5	8
β-strand	120	1	9
α-helix	121-122	2
β-strand	123-127	5	10
β-strand	138-148	11	10
β-strand	149	1	9
β-strand	154-157	4	11
α-helix	158-160	3
β-strand	166-168	3	10
α-helix	169-171	3
β-strand	172-174	3	10
β-strand	177-187	11	10
β-strand	196-202	7	11
α-helix	203-205	3
β-strand	207-213	7	11

Chain F: 9 helices, 21 β-strands

Element	Residues	Length	Sheet
β-strand	4-5	2	12
β-strand	10-13	4	13
β-strand	19-25	7	12
β-strand	33-37	5	13
β-strand	44-48	5	13
β-strand	52-53	2	13
α-helix	54	1
β-strand	61-66	6	12
β-strand	69-74	6	12
α-helix	79-81	3
β-strand	83-89	7	13
α-helix	95	1
β-strand	96-97	2	13
β-strand	101-105	5	13
α-helix	106	1
β-strand	110	1	14
α-helix	111-112	2
β-strand	113-117	5	15
α-helix	118-120	3
α-helix	121-125	5
β-strand	128-138	11	15
β-strand	139	1	14
β-strand	144-149	6	16
β-strand	152-154	3	16
β-strand	158-162	5	15
α-helix	163-166	4
β-strand	172-181	10	15
α-helix	182-187	6
β-strand	190-196	7	16
β-strand	204-209	6	16

Chain G: 7 helices, 22 β-strands

Element	Residues	Length	Sheet
β-strand	3-6	4	17
β-strand	10-12	3	18
β-strand	18-25	8	17
α-helix	29-31	3
β-strand	34-39	6	18
β-strand	45-51	7	18
β-strand	58-60	3	18
α-helix	62-64	3
β-strand	68-73	6	17
β-strand	78-83	6	17
α-helix	88-90	3
β-strand	92-98	7	18
β-strand	105-106	2	18
β-strand	110-114	5	18
β-strand	120	1	19
α-helix	121-122	2
β-strand	123-127	5	20
β-strand	138-148	11	20
β-strand	149	1	19
β-strand	154-157	4	21
α-helix	158-160	3
β-strand	162	1	21
β-strand	166-168	3	20
α-helix	169-171	3
β-strand	172-174	3	20
β-strand	177-187	11	20
β-strand	196-202	7	21
α-helix	203-205	3
β-strand	207-213	7	21

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Potassium channel subfamily K member 4	A, B	protein	309	Homo sapiens	Q9NYG8 (AlphaFold model)
Antibody FAB fragment light chain	D, F	protein	211	Mus musculus
Antibody FAB fragment heavy chain	E, G	protein	217	Mus musculus

Sequence of entity 1 (A, B), FASTA

>4I9W_1 Potassium channel subfamily K member 4 (chains A, B)
MTTAPQEPPARPLQAGSGAGPAPGRAMRSTTLLALLALVLLYLVSGALVFRALEQPHEQQ
AQRELGEVREKFLRAHPCVSDQELGLLIKEVADALGGGADPETQSTSQSSHSAWDLGSAF
FFSGTIITTIGYGNVALRTDAGRLFCIFYALVGIPLFGILLAGVGDRLGSSLRHGIGHIE
AIFLKWHVPPELVRVLSAMLFLLIGCLLFVLTPTFVFCYMEDWSKLEAIYFVIVTLTTVG
FGDYVAGADPRQDSPAYQPLVWFWILLGLAYFASVLTTIGNWLRVVSRRTRAEMGGLTAQ
SNSLEVLFQ

Sequence of entity 2 (D, F), FASTA

>4I9W_2 ANTIBODY FAB FRAGMENT LIGHT CHAIN (chains D, F)
QIVLTQSPAIMSASPGEKVTMTCSASSSVSYMHWYQQKSGTSPKRWIYDTSKLASGVPAR
FSGSGSGTSYSLTISSMEAEDAATYYCQQWSNSPPTFGAGAKLELKRADAAPTVSIFPPS
SEQLTSGGASVVCFLNNFYPKDINVKWKIDGSERQNGVLNSWTDQDSKDSTYSMSSTLTL
TKDEYERHNSYTCEATHKTSTSPIVKSFNRN

Sequence of entity 3 (E, G), FASTA

>4I9W_3 ANTIBODY FAB FRAGMENT HEAVY CHAIN (chains E, G)
EVQLQQSGPELVKPGASMKTSCKVSGYSFTGYIMNWVKQRHGKNLEWIGLINPNTGYTTY
NQKFKGKATLTVDKSSSTAYMELLSLTSEDSAIYYCTRGNYVFDYWGQGTTLTVSSAKTT
PPSVYPLAPGSAAQTNSMVTLGCLVKGYFPEPVTVTWNSGSLSSGVHTFPAVLQSDLYTL
SSSVTVPSSSWPSETVTCNVAHPASSTKVDKKIVPRD

Ligands and cofactors

ID	Name	Formula	Copies
CA	Calcium ion	Ca	2

Water and common crystallization additives (K) are not listed.

Primary citation

Domain-swapped chain connectivity and gated membrane access in a Fab-mediated crystal of the human TRAAK K+ channel. Brohawn, S.G., Campbell, E.B., Mackinnon, R. Proc Natl Acad Sci U S A (2013) 110:2129-2134. DOI 10.1073/pnas.1218950110 · PubMed

Other PDB entries of the same protein (UniProt Q9NYG8 (AlphaFold model), which also has an AlphaFold model), best resolution first:

7LJ5 2.26 Å, Human TRAAK K+ channel FHIEG mutant A198E in a K+ bound conductive conformation
4WFE 2.5 Å, Human TRAAK K+ channel in a K+ bound conductive conformation
4WFF 2.5 Å, Human TRAAK K+ channel in a K+ bound nonconductive conformation
7LJA 2.77 Å, Human TRAAK K+ channel FHEIG mutant A198E in a Tl+ bound conductive conformation
7LJ4 2.78 Å, Human TRAAK K+ channel FHEIG mutant A270P in a K+ bound conductive conformation
7LJB 2.97 Å, Human TRAAK K+ channel mutant G158D in a K+ bound conductive conformation
4WFG 3.0 Å, Human TRAAK K+ channel in a Tl+ bound conductive conformation
4WFH 3.01 Å, Human TRAAK K+ channel in a Tl+ bound nonconductive conformation
4RUE 3.3 Å, Human K2P4.1 (TRAAK) potassium channel, G124I mutant
3UM7 3.31 Å, Crystal structure of the human two pore domain K+ ion channel TRAAK (K2P4.1)
4RUF 3.4 Å, Human K2P4.1 (TRAAAK) potassium channel, W262S mutant

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