9MY4: PDB entry 9MY4

Structure of Xenopus KCNQ1(E150R/R221E)-CaM with the VSD in the intermediate state. Determined by electron microscopy at 3.53 Å resolution. Released 15 Oct 2025.

Method: Electron microscopy
Resolution: 3.53 Å
Organisms: Xenopus laevis, Homo sapiens
Chains: 8
Atoms: 14,992
Mol. weight: 316.91 kDa
Released: 15 Oct 2025

Explore 9MY4 in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

9MY4 contains 108 α-helices and 16 β-strands across 8 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, C, E and G: 18 helices, 0 β-strands

Element	Residues	Length
α-helix	96-104	9
α-helix	110-134	25
α-helix	139-167	29
α-helix	168-170	3
α-helix	177-184	8
α-helix	187-204	18
α-helix	217-223	7
α-helix	225-229	5
α-helix	236-247	12
α-helix	249-273	25
α-helix	289-299	11
α-helix	313-347	35
α-helix	351-353	3
α-helix	354-356	3
α-helix	358-373	16
α-helix	380-383	4
α-helix	499-520	22
α-helix	527-552	26

Chains B, D, F and H: 9 helices, 4 β-strands

Element	Residues	Length	Sheet
α-helix	13-20	8
β-strand	27-28	2	1
α-helix	30-38	9
α-helix	46-54	9
β-strand	64-65	2	1
α-helix	66-73	8
α-helix	80-92	13
β-strand	102	1	2
α-helix	103-112	10
α-helix	116-118	3
α-helix	119-127	9
β-strand	136	1	2
α-helix	139-145	7

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Potassium voltage-gated channel subfamily KQT member 1	A, C, E, G	protein	545	Xenopus laevis	P70057 (AlphaFold model)
Calmodulin-1	B, D, F, H	protein	149	Homo sapiens	P0DP23 (AlphaFold model)

Sequence of entity 1 (A, C, E, G), FASTA

>9MY4_1 Potassium voltage-gated channel subfamily KQT member 1 (chains A, C, E, G)
MATDPPRPTINLDPRVSIYSGRRPLLSRTNIQGRVYNFLERPTGWKCFVYHFTVFLIVLI
CLIFSVLSTIQQYNNLATETLFWMRIVLVVFFGAEYVVRLWSAGCRSKYVGVWGRLRFAR
KPISVIDLIVVVASVIVLCVGSNGQVFATSAIRGIEFLQILRMLHVDRQGGTWRLLGSVV
FIHRQELITTLYIGFLGLIFSSYFVYLAEKDAIDSSGEYQFGSYADALWWGVVTVTTIGY
GDKVPQTWIGKTIASCFSVFAISFFALPAGILGSGFALKVQQKQRQKHFNRQIPAAASLI
QTAWRCYAAENPDSATWKIYIRKQSRNHHLMSPSPKPKKSAMVKKKKIRTERDEGSTDKM
LNIPHITYDHVADDRKNDGYSVESYENTVRKPFGFLDPSTGPFIRTSSFTDDLDMEGDTL
LTPITHISELKEHHRAAIKVIRRMQYFVAKKKFQQARKPYDVRDVIEQYSQGHLNLMVRI
KELQRRLDQSLGKPSLFLSVSDKVKDKGINTIGSRLNRVEDKVTQMDHKLNLITDMLHHL
LTNQQ

Sequence of entity 2 (B, D, F, H), FASTA

>9MY4_2 Calmodulin-1 (chains B, D, F, H)
MADQLTEEQIAEFKEAFSLFDKDGDGTITTKELGTVMRSLGQNPTEAELQDMINEVDADG
NGTIDFPEFLTMMARKMKDTDSEEEIREAFRVFDKDGNGYISAAELRHVMTNLGEKLTDE
EVDEMIREADIDGDGQVNYEEFVQMMTAK

Primary citation

A physiologically-relevant intermediate state structure of a voltage-gated potassium channel. Kyriakis, E., Sastre, D., Eldstrom, J. et al. Nat Commun (2025) 16:8814-8814. DOI 10.1038/s41467-025-64060-3 · PubMed

Other PDB entries of the same protein (UniProt P70057 (AlphaFold model), which also has an AlphaFold model), best resolution first:

9MY3 3.46 Å, Structure of Xenopus KCNQ1-CaM in GDN
5VMS 3.7 Å, CryoEM structure of Xenopus KCNQ1 channel
10NL 3.81 Å, Xenopus KCNQ1 in complex with UCL2077
7TCP 3.84 Å, Structure of Xenopus KCNQ1-CaM
7TCI 3.9 Å, Structure of Xenopus KCNQ1-CaM in complex with ML277
10NK 3.95 Å, Xenopus KCNQ1 Intermediate State (E1R/R2E) in complex with UCL2077

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