9KCI: Human sodium pump WT in (2K+)E2-AlF state

Cryo-EM structure of human sodium pump WT in (2K+)E2-AlF state. Determined by electron microscopy at 2.9 Å resolution. Released 12 Nov 2025.

Method: Electron microscopy
Resolution: 2.9 Å
Organism: Homo sapiens
Chains: 3
Atoms: 10,486
Mol. weight: 165.95 kDa
Ligands: ALF, MG, PCW, CLR
Released: 12 Nov 2025

Explore 9KCI in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

9KCI contains 67 α-helices and 48 β-strands across 3 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: 58 helices, 32 β-strands

Element	Residues	Length	Sheet
α-helix	48-55	8
β-strand	63	1	1
α-helix	65-75	11
α-helix	82-84	3
α-helix	88-95	8
α-helix	99-122	24
α-helix	129-149	21
α-helix	157-162	6
β-strand	168-173	6	1
β-strand	176-181	6	1
α-helix	182-184	3
β-strand	190-194	5	1
α-helix	197	1
β-strand	198	1	1
α-helix	199	1
β-strand	202-214	13	1
α-helix	216-219	4
β-strand	224-227	4	1
β-strand	242-243	2	1
β-strand	248-260	13	1
α-helix	262-264	3
α-helix	266-276	11
α-helix	283-312	30
α-helix	317-331	15
α-helix	336-352	17
β-strand	356-358	3	2
α-helix	363-369	7
β-strand	372-375	4	2
β-strand	382	1	3
β-strand	387-393	7	4
β-strand	396-399	4	4
α-helix	416-427	12
β-strand	432-433	2	5
α-helix	434	1
α-helix	442-444	3
β-strand	447-448	2	5
α-helix	451-463	13
α-helix	467-473	7
β-strand	476-480	5	4
β-strand	488-494	7	4
β-strand	503-509	7	4
α-helix	511-514	4
α-helix	515-517	3
β-strand	518-523	6	4
β-strand	526-529	4	4
α-helix	532-546	15
β-strand	551-559	9	4
β-strand	583-592	10	4
α-helix	594	1
β-strand	595	1	3
α-helix	596	1
α-helix	599-608	10
β-strand	612-616	5	2
α-helix	621-631	11
α-helix	641-648	8
α-helix	652-654	3
α-helix	657-659	3
β-strand	662-666	5	2
α-helix	667-671	5
α-helix	675-684	10
β-strand	687-691	5	2
α-helix	695-707	13
β-strand	712-716	5	2
α-helix	719-721	3
α-helix	722-727	6
β-strand	730-734	5	2
α-helix	740-744	5
β-strand	748-750	3	2
α-helix	756-781	26
α-helix	784-796	13
α-helix	798-800	3
α-helix	804-809	6
α-helix	810-814	5
α-helix	816-820	5
α-helix	821-824	4
α-helix	835-838	4
α-helix	847-851	5
α-helix	852-857	6
α-helix	858-875	18
α-helix	880-883	4
α-helix	887-890	4
β-strand	898-899	2	6
β-strand	905-906	2	6
α-helix	908-937	30
α-helix	944-947	4
α-helix	952-970	19
α-helix	974-977	4
α-helix	985-989	5
α-helix	992-1010	19
α-helix	1016-1021	6

Chain B: 8 helices, 16 β-strands

Element	Residues	Length	Sheet
α-helix	15-19	5
β-strand	28	1	7
β-strand	31	1	7
α-helix	33-63	31
β-strand	80	1	8
β-strand	81-84	4	9
α-helix	86-87	2
β-strand	92-94	3	10
α-helix	104-114	11
α-helix	121-124	4
β-strand	126	1	11
β-strand	144	1	11
α-helix	148-150	3
β-strand	170-175	6	9
α-helix	176-177	2
β-strand	179	1	12
β-strand	189-193	5	10
β-strand	201-203	3	9
α-helix	212-214	3
β-strand	217	1	12
β-strand	230-235	6	9
β-strand	246-252	7	10
β-strand	268	1	8
β-strand	270-276	7	10

Chain C: 1 helix, 0 β-strands

Element	Residues	Length	Sheet
α-helix	139-161	23

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Sodium/potassium-transporting ATPase subunit alpha-1	A	protein	985	Homo sapiens	P05023 (AlphaFold model)
Sodium/potassium-transporting ATPase subunit beta-3	B	protein	279	Homo sapiens	P54709 (AlphaFold model)
FXYD domain-containing ion transport regulator 5	C	protein	178	Homo sapiens	Q96DB9 (AlphaFold model)

Sequence of entity 1 (A), FASTA

>9KCI_1 Sodium/potassium-transporting ATPase subunit alpha-1 (chains A)
VSMDDHKLSLDELHRKYGTDLSRGLTSARAAEILARDGPNALTPPPTTPEWIKFCRQLFG
GFSMLLWIGAILCFLAYSIQAATEEEPQNDNLYLGVVLSAVVIITGCFSYYQEAKSSKIM
ESFKNMVPQQALVIRNGEKMSINAEEVVVGDLVEVKGGDRIPADLRIISANGCKVDNSSL
TGESEPQTRSPDFTNENPLETRNIAFFSTNCVEGTARGIVVYTGDRTVMGRIATLASGLE
GGQTPIAAEIEHFIHIITGVAVFLGVSFFILSLILEYTWLEAVIFLIGIIVANVPEGLLA
TVTVCLTLTAKRMARKNCLVKNLEAVETLGSTSTICSDKTGTLTQNRMTVAHMWFDNQIH
EADTTENQSGVSFDKTSATWLALSRIAGLCNRAVFQANQENLPILKRAVAGDASESALLK
CIELCCGSVKEMRERYAKIVEIPFNSTNKYQLSIHKNPNTSEPQHLLVMKGAPERILDRC
SSILLHGKEQPLDEELKDAFQNAYLELGGLGERVLGFCHLFLPDEQFPEGFQFDTDDVNF
PIDNLCFVGLISMIDPPRAAVPDAVGKCRSAGIKVIMVTGDHPITAKAIAKGVGIISEGN
ETVEDIAARLNIPVSQVNPRDAKACVVHGSDLKDMTSEQLDDILKYHTEIVFARTSPQQK
LIIVEGCQRQGAIVAVTGDGVNDSPALKKADIGVAMGIAGSDVSKQAADMILLDDNFASI
VTGVEEGRLIFDNLKKSIAYTLTSNIPEITPFLIFIIANIPLPLGTVTILCIDLGTDMVP
AISLAYEQAESDIMKRQPRNPKTDKLVNERLISMAYGQIGMIQALGGFFTYFVILAENGF
LPIHLLGLRVDWDDRWINDVEDSYGQQWTYEQRKIVEFTCHTAFFVSIVVVQWADLVICK
TRRNSVFQQGMKNKILIFGLFEETALAAFLSYCPGMGVALRMYPLKPTWWFCAFPYSLLI
FVYDEVRKLIIRRRPGGWVEKETYY

Sequence of entity 2 (B), FASTA

>9KCI_2 Sodium/potassium-transporting ATPase subunit beta-3 (chains B)
MTKNEKKSLNQSLAEWKLFIYNPTTGEFLGRTAKSWGLILLFYLVFYGFLAALFSFTMWV
MLQTLNDEVPKYRDQIPSPGLMVFPKPVTALEYTFSRSDPTSYAGYIEDLKKFLKPYTLE
EQKNLTVCPDGALFEQKGPVYVACQFPISLLQACSGMNDPDFGYSQGNPCILVKMNRIIG
LKPEGVPRIDCVSKNEDIPNVAVYPHNGMIDLKYFPYYGKKLHVGYLQPLVAVQVSFAPN
NTGKEVTVECKIDGSANLKSQDDRDKFLGRVMFKITARA

Sequence of entity 3 (C), FASTA

>9KCI_3 FXYD domain-containing ion transport regulator 5 (chains C)
MSPSGRLCLLTIVGLILPTRGQTLKDTTSSSSADSTIMDIQVPTRAPDAVYTELQPTSPT
PTWPADETPQPQTQTQQLEGTDGPLVTDPETHKSTKAAHPTDDTTTLSERPSPSTDVQTD
PQTLKPSGFHEDDPFFYDEHTLRKRGLLVAAVLFITGIIILTSGKCRQLSRLCRNRCR

Ligands and cofactors

ID	Name	Formula	Copies
ALF	Tetrafluoroaluminate ion	Al F4	1
MG	Magnesium ion	Mg	1
PCW	1,2-dioleoyl-sn-glycero-3-phosphocholine	C44 H85 N O8 P	6
CLR	Cholesterol	C27 H46 O	3

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

Primary citation

Structural basis of a sodium pump quaternary complex leading phospholipid scrambling in the living cell. Dou, Y., Abe, K., Suzuki, J. To be published.

Other PDB entries of the same protein (UniProt P05023 (AlphaFold model), which also has an AlphaFold model), best resolution first:

9WAJ 2.39 Å, Cryo-EM structure of a human sodium pump wildtype in ouabain-bound E2P state
24RC 2.61 Å, Cryo-EM structure of human sodium pump W931R mutant in K+-occluded E2-Pi state
7E20 2.7 Å, Cryo EM structure of a K+-bound Na+,K+-ATPase in the E2 state
9WAK 2.86 Å, Cryo-EM structure of a human sodium pump W931R mutant in ouabain-bound E2P state
7E21 2.9 Å, Cryo EM structure of a Na+-bound Na+,K+-ATPase in the E1 state with ATP-gamma-S
9KCK 2.9 Å, Cryo-EM structure of human sodium pump E1003K in (2K+)E2-AlF state
9KCL 2.9 Å, Cryo-EM structure of human sodium pump E1003K complexed with NDRG3 in (2Na+)E1-AMPPCP…
9KCM 2.9 Å, Cryo-EM structure of human sodium pump E1003K complexed with NDRG3 and TMX2 in…
9KCG 3.1 Å, Cryo-EM structure of human sodium pump WT in (3Na+)E1-AMPPCP state
9KCJ 3.1 Å, Cryo-EM structure of human sodium pump E1003 in (3Na+)E1-AMPPCP state
7E1Z 3.2 Å, Cryo EM structure of a Na+-bound Na+,K+-ATPase in the E1 state
9KCR 3.2 Å, Cryo-EM structure of human sodium pump E1003K complexed with NDRG3 in (2Na+)E1 state

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