9U7F: Human KCNQ1-KCNE1-CaM complex

structure of human KCNQ1-KCNE1-CaM complex. Determined by electron microscopy at 2.9 Å resolution. Released 5 Nov 2025.

Method: Electron microscopy
Resolution: 2.9 Å
Organism: Homo sapiens
Chains: 12
Atoms: 17,224
Mol. weight: 430.04 kDa
Ligands: PT5, CA
Released: 5 Nov 2025

Explore 9U7F in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

9U7F contains 120 α-helices and 24 β-strands across 12 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.

Chains A, D, G and J: 20 helices, 2 β-strands

Element	Residues	Length	Sheet
α-helix	106-114	9
α-helix	120-142	23
α-helix	151-176	26
α-helix	187-194	8
α-helix	197-214	18
α-helix	221-230	10
α-helix	231-234	4
α-helix	235-238	4
α-helix	248-257	10
α-helix	260-283	24
β-strand	288	1	1
β-strand	294	1	1
α-helix	299-310	12
α-helix	323-331	9
α-helix	338-340	3
α-helix	342-356	15
α-helix	357-359	3
α-helix	361-363	3
α-helix	368-380	13
α-helix	392-394	3
α-helix	514-532	19
α-helix	538-568	31

Chains B, E, H and K: 8 helices, 4 β-strands

Element	Residues	Length	Sheet
α-helix	7-21	15
β-strand	28	1	2
α-helix	30-40	11
α-helix	46-54	9
β-strand	64	1	2
α-helix	66-74	9
α-helix	80-91	12
β-strand	100-102	3	3
α-helix	103-110	8
α-helix	119-129	11
β-strand	136-138	3	3
α-helix	139-148	10

Chains C, F, I and L: 2 helices, 0 β-strands

Element	Residues	Length	Sheet
α-helix	43-61	19
α-helix	62-64	3

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Potassium voltage-gated channel subfamily KQT member 1	A, D, G, J	protein	676	Homo sapiens	P51787 (AlphaFold model)
Calmodulin-1	B, E, H, K	protein	149	Homo sapiens	P0DP23 (AlphaFold model)
Potassium voltage-gated channel subfamily E member 1	C, F, I, L	protein	129	Homo sapiens	P15382 (AlphaFold model)

Sequence of entity 1 (A, D, G, J), FASTA

>9U7F_1 Potassium voltage-gated channel subfamily KQT member 1 (chains A, D, G, J)
MAAASSPPRAERKRWGWGRLPGARRGSAGLAKKCPFSLELAEGGPAGGALYAPIAPGAPG
PAPPASPAAPAAPPVASDLGPRPPVSLDPRVSIYSTRRPVLARTHVQGRVYNFLERPTGW
KCFVYHFAVFLIVLVCLIFSVLSTIEQYAALATGTLFWMEIVLVVFFGTEYVVRLWSAGC
RSKYVGLWGRLRFARKPISIIDLIVVVASMVVLCVGSKGQVFATSAIRGIRFLQILRMLH
VDRQGGTWRLLGSVVFIHRQELITTLYIGFLGLIFSSYFVYLAEKDAVNESGRVEFGSYA
DALWWGVVTVTTIGYGDKVPQTWVGKTIASCFSVFAISFFALPAGILGSGFALKVQQKQR
QKHFNRQIPAAASLIQTAWRCYAAENPDSSTWKIYIRKAPRSHTLLSPSPKPKKSVVVKK
KKFKLDKDNGVTPGEKMLTVPHITCDPPEERRLDHFSVDGYDSSVRKSPTLLEVSMPHFM
RTNSFAEDLDLEGETLLTPITHISQLREHHRATIKVIRRMQYFVAKKKFQQARKPYDVRD
VIEQYSQGHLNLMVRIKELQRRLDQSIGKPSLFISVSEKSKDRGSNTIGARLNRVEDKVT
QLDQRLALITDMLHQLLSLHGGSTPGSGGPPREGGAHITQPCGSGGSVDPELFLPSNTLP
TYEQLTVPRRGPDEGS

Sequence of entity 2 (B, E, H, K), FASTA

>9U7F_2 Calmodulin-1 (chains B, E, H, K)
MADQLTEEQIAEFKEAFSLFDKDGDGTITTKELGTVMRSLGQNPTEAELQDMINEVDADG
NGTIDFPEFLTMMARKMKDTDSEEEIREAFRVFDKDGNGYISAAELRHVMTNLGEKLTDE
EVDEMIREADIDGDGQVNYEEFVQMMTAK

Sequence of entity 3 (C, F, I, L), FASTA

>9U7F_3 Potassium voltage-gated channel subfamily E member 1 (chains C, F, I, L)
MILSNTTAVTPFLTKLWQETVQQGGNMSGLARRSPRSSDGKLEALYVLMVLGFFGFFTLG
IMLSYIRSKKLEHSNDPFNVYIESDAWQEKDKAYVQARVLESYRSCYVVENHLAIEQPNT
HLPETKPSP

Ligands and cofactors

ID	Name	Formula	Copies
PT5	[(2R)-1-octadecanoyloxy-3-[oxidanyl-[(1R,2R,3S,4R,5R,6S)-2,3,6-tris(oxidanyl)-4…	C47 H85 O19 P3	4
CA	Calcium ion	Ca	8

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

Primary citation

Secondary structure transitions and dual PIP2 binding define cardiac KCNQ1-KCNE1 channel gating. Zhong, L., Lin, X., Cheng, X. et al. Cell Res (2025) 35:887-899. DOI 10.1038/s41422-025-01182-9 · PubMed

Other PDB entries of the same protein (UniProt P51787 (AlphaFold model), which also has an AlphaFold model), best resolution first:

3HFE 1.7 Å, A trimeric form of the Kv7.1 A domain Tail
3BJ4 2.0 Å, The KCNQ1 (Kv7.1) C-terminus, a multi-tiered scaffold for subunit assembly and protein…
7VVH 2.3 Å, Crystal Structure of the Kv7.1 C-terminal Domain in Complex with Calmodulin disease…
3HFC 2.45 Å, A trimeric form of the Kv7.1 A domain Tail, L602M/L606M mutant Semet
7XNN 2.5 Å, human KCNQ1-CaM-ML277-PIP2 complex in state B
9UJ4 2.59 Å, Structure of human KCNQ1-CaM complex
7XNK 2.6 Å, human KCNQ1-CaM in complex with ML277
7VUO 2.68 Å, Crystal Structure of the Kv7.1 C-terminal Domain in Complex with Calmodulin disease…
9VEC 2.7 Å, structure of human KCNQ1-KCNE1-CaM complex
4V0C 2.86 Å, Crystal Structure of the Kv7.1 proximal C-terminal Domain in Complex with Calmodulin
8SIK 2.9 Å, KCNQ1 with voltage sensor in the up conformation
4UMO 3.0 Å, Crystal Structure of the Kv7.1 proximal C-terminal Domain in Complex with Calmodulin

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