9VEC: Human KCNQ1-KCNE1-CaM complex

structure of human KCNQ1-KCNE1-CaM complex. Determined by electron microscopy at 2.7 Å resolution. Released 20 Aug 2025.

Method: Electron microscopy
Resolution: 2.7 Å
Organism: Homo sapiens
Chains: 12
Atoms: 15,880
Mol. weight: 374.69 kDa
Ligands: CA
Released: 20 Aug 2025

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

Secondary structure: helices and β-sheets

9VEC contains 116 α-helices and 16 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: 19 helices, 0 β-strands

Element	Residues	Length
α-helix	107-114	8
α-helix	122-142	21
α-helix	169-177	9
α-helix	178-180	3
α-helix	186-194	9
α-helix	197-215	19
α-helix	225-228	4
α-helix	230-236	7
α-helix	237-240	4
α-helix	246-257	12
α-helix	259-284	26
α-helix	299-310	12
α-helix	323-357	35
α-helix	361-363	3
α-helix	364-366	3
α-helix	368-383	16
α-helix	392-395	4
α-helix	508-532	25
α-helix	538-567	30

Chains B, E, H and K: 9 helices, 4 β-strands

Element	Residues	Length	Sheet
α-helix	9-21	13
β-strand	28	1	3
α-helix	30-38	9
α-helix	46-53	8
β-strand	64	1	3
α-helix	66-73	8
α-helix	80-91	12
β-strand	100-102	3	4
α-helix	103-112	10
α-helix	116-118	3
α-helix	119-126	8
β-strand	136-138	3	4
α-helix	139-148	10

Chains C, F, I and L: 1 helix, 0 β-strands

Element	Residues	Length	Sheet
α-helix	43-64	22

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
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)
Potassium voltage-gated channel subfamily KQT member 1	A, D, G, J	protein	546	Homo sapiens	P51787 (AlphaFold model)

Sequence of entity 1 (B, E, H, K), FASTA

>9VEC_1 Calmodulin-1 (chains B, E, H, K)
MADQLTEEQIAEFKEAFSLFDKDGDGTITTKELGTVMRSLGQNPTEAELQDMINEVDADG
NGTIDFPEFLTMMARKMKDTDSEEEIREAFRVFDKDGNGYISAAELRHVMTNLGEKLTDE
EVDEMIREADIDGDGQVNYEEFVQMMTAK

Sequence of entity 2 (C, F, I, L), FASTA

>9VEC_2 Potassium voltage-gated channel subfamily E member 1 (chains C, F, I, L)
MILSNTTAVTPFLTKLWQETVQQGGNMSGLARRSPRSSDGCLEALYVLMVLGFFGFFTLG
IMLSYIRSKKLEHSNDPFNVYIESDAWQEKDKAYVQARVLESYRSCYVVENHLAIEQPNT
HLPETKPSP

Sequence of entity 3 (A, D, G, J), FASTA

>9VEC_3 Potassium voltage-gated channel subfamily KQT member 1 (chains A, D, G, J)
MASDLGPRPPVSLDPRVSIYSTRRPVLARTHVQGRVYNFLERPTGWKCFVYHFAVFLIVL
VCLIFSVLSTCEQYAALATGTLFWMEIVLVVFFGTEYVVRLWSAGCRSKYVGLWGRLRFA
RKPISIIDLIVVVASMVVLCVGSKGQVFATSAIRGIRFLQILRMLHVDRQGGTWRLLGSV
VFIHRQELITTLYIGFLGLIFSSYFVYLAEKDAVNESGRVEFGSYADALWWGVVTVTTIG
YGDKVPQTWVGKTIASCFSVFAISFFALPAGILGSGFALKVQQKQRQKHFNRQIPAAASL
IQTAWRCYAAENPDSSTWKIYIRKAPRSHTLLSPSPKPKKSVVVKKKKFKLDKDNGVTPG
EKMLTVPHITCDPPEERRLDHFSVDGYDSSVRKSPTLLEVSMPHFMRTNSFAEDLDLEGE
TLLTPITHISQLREHHRATIKVIRRMQYFVAKKKFQQARKPYDVRDVIEQYSQGHLNLMV
RIKELQRRLDQSIGKPSLFISVSEKSKDRGSNTIGARLNRVEDKVTQLDQRLALITDMLH
QLLSLH

Ligands and cofactors

ID	Name	Formula	Copies
CA	Calcium ion	Ca	8

Primary citation

Mechanisms of KCNQ1 gating modulation by KCNE1/3 for cell-specific function. Cui, C., Zhao, L., Kermani, A.A. et al. Cell Res (2025) 35:876-886. DOI 10.1038/s41422-025-01152-1 · PubMed

Other PDB entries of the same protein (UniProt P0DP23 (AlphaFold model), which also has an AlphaFold model), best resolution first:

9MXD 1.17 Å, Human E104A calmodulin:MLCK RM20 complex
7BF1 1.24 Å, Ca2+-Calmodulin in complex with peptide from brain-type creatine kinase in extended 1:2…
6XXX 1.25 Å, 1.25 Angstrom crystal structure of Ca/CaM A102V:RyR2 peptide complex
4DJC 1.35 Å, 1.35 A crystal structure of the NaV1.5 DIII-IV-Ca/CaM complex
7BF2 1.43 Å, Ca2+-Calmodulin in complex with human muscle form creatine kinase peptide in extended…
2F3Y 1.45 Å, Calmodulin/IQ domain complex
2W73 1.45 Å, High-resolution structure of the complex between calmodulin and a peptide from…
4LZX 1.5 Å, Complex of IQCG and Ca2+-free CaM
5V03 1.58 Å, A positive allosteric modulator binding pocket in SK2 ion channels is shared by Riluzole…
9MVW 1.58 Å, Crystal structure of S101F calmodulin - CaM:RM20 analog complex
2F3Z 1.6 Å, Calmodulin/IQ-AA domain complex
6M7H 1.6 Å, Structure of calmodulin with KN93

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