10NK: Xenopus KCNQ1 Intermediate State

Xenopus KCNQ1 Intermediate State (E1R/R2E) in complex with UCL2077. Determined by electron microscopy at 3.95 Å resolution. Released 2 Sept 2026.

Method: Electron microscopy
Resolution: 3.95 Å
Organisms: Homo sapiens, Xenopus laevis
Chains: 8
Atoms: 14,500
Mol. weight: 317.61 kDa
Ligands: A1C6W
Released: 2 Sept 2026

Explore 10NK in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

10NK contains 106 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 and F: 18 helices, 0 β-strands

Element	Residues	Length
α-helix	98-104	7
α-helix	110-136	27
α-helix	140-162	23
α-helix	163-167	5
α-helix	172-174	3
α-helix	177-184	8
α-helix	187-204	18
α-helix	217-229	13
α-helix	236-274	39
α-helix	277-279	3
α-helix	289-300	12
α-helix	313-329	17
α-helix	331-346	16
α-helix	357-372	16
α-helix	373-375	3
α-helix	380-383	4
α-helix	498-521	24
α-helix	527-548	22

Chains B and C: 9 helices, 4 β-strands

Element	Residues	Length	Sheet
α-helix	11-13	3
α-helix	14-17	4
β-strand	27-28	2	1
α-helix	30-37	8
α-helix	46-56	11
β-strand	64-65	2	1
α-helix	66-74	9
α-helix	80-92	13
β-strand	101	1	2
α-helix	103-112	10
α-helix	119-127	9
β-strand	137	1	2
α-helix	139-145	7

Chains D and E: 9 helices, 4 β-strands

Element	Residues	Length	Sheet
α-helix	14-17	4
β-strand	27-28	2	3
α-helix	30-38	9
α-helix	46-54	9
β-strand	64-65	2	3
α-helix	66-74	9
α-helix	80-91	12
β-strand	100-101	2	4
α-helix	103-112	10
α-helix	116-118	3
α-helix	119-128	10
β-strand	137-138	2	4
α-helix	139-143	5

Chains G and H: 17 helices, 0 β-strands

Element	Residues	Length
α-helix	96-105	10
α-helix	110-134	25
α-helix	137-141	5
α-helix	143-167	25
α-helix	168-170	3
α-helix	172-174	3
α-helix	176-183	8
α-helix	187-204	18
α-helix	217-229	13
α-helix	237-247	11
α-helix	249-273	25
α-helix	277-279	3
α-helix	289-299	11
α-helix	313-346	34
α-helix	357-375	19
α-helix	498-522	25
α-helix	527-548	22

Molecules and chains

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

Sequence of entity 1 (B, C, D, E), FASTA

>10NK_1 Calmodulin-1 (chains B, C, D, E)
MADQLTEEQIAEFKEAFSLFDKDGDGTITTKELGTVMRSLGQNPTEAELQDMINEVDADG
NGTIDFPEFLTMMARKMKDTDSEEEIREAFRVFDKDGNGYISAAELRHVMTNLGEKLTDE
EVDEMIREADIDGDGQVNYEEFVQMMTAK

Sequence of entity 2 (A, F, G, H), FASTA

>10NK_2 Potassium voltage-gated channel subfamily KQT member 1 (chains A, F, G, H)
MATDPPRPTINLDPRVSIYSGRRPLLSRTNIQGRVYNFLERPTGWKCFVYHFTVFLIVLI
CLIFSVLSTIQQYNNLATETLFWMRIVLVVFFGAEYVVRLWSAGCRSKYVGVWGRLRFAR
KPISVIDLIVVVASVIVLCVGSNGQVFATSAIRGIEFLQILRMLHVDRQGGTWRLLGSVV
FIHRQELITTLYIGFLGLIFSSYFVYLAEKDAIDSSGEYQFGSYADALWWGVVTVTTIGY
GDKVPQTWIGKTIASCFSVFAISFFALPAGILGSGFALKVQQKQRQKHFNRQIPAAASLI
QTAWRCYAAENPDSATWKIYIRKQSRNHHLMSPSPKPKKSAMVKKKKIRTERDEGSTDKM
LNIPHITYDHVADDRKNDGYSVESYENTVRKPFGFLDPSTGPFIRTSSFTDDLDMEGDTL
LTPITHISELKEHHRAAIKVIRRMQYFVAKKKFQQARKPYDVRDVIEQYSQGHLNLMVRI
KELQRRLDQSLGKPSLFLSVSDKVKDKGINTIGSRLNRVEDKVTQMDHKLNLITDMLHHL
LTNQQ

Ligands and cofactors

ID	Name	Formula	Copies
A1C6W	1,1,1-triphenyl-N-[(pyridin-3-yl)methyl]methanamine	C25 H22 N2	2

Primary citation

Structural and kinetic mechanisms of state-dependent potassium channel inhibition. Kyriakis, E., Roscioni, A., Eldstrom, J. et al. Sci Adv (2026).

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

Browse structure collections

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