7TCI: Xenopus KCNQ1-CaM

Structure of Xenopus KCNQ1-CaM in complex with ML277. Determined by electron microscopy at 3.9 Å resolution. Released 6 Jul 2022.

Method: Electron microscopy
Resolution: 3.9 Å
Organisms: Xenopus laevis, Homo sapiens
Chains: 8
Atoms: 15,084
Mol. weight: 320.43 kDa
Ligands: I0S, CA
Released: 6 Jul 2022

Explore 7TCI in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

7TCI contains 108 α-helices and 24 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, 2 β-strands

Element	Residues	Length	Sheet
α-helix	96-105	10
α-helix	110-134	25
α-helix	140-167	28
α-helix	176-184	9
α-helix	187-205	19
α-helix	219-227	9
α-helix	228-231	4
α-helix	233-235	3
α-helix	238-247	10
α-helix	249-273	25
β-strand	278	1	1
β-strand	284	1	1
α-helix	289-300	12
α-helix	313-349	37
α-helix	352-353	2
α-helix	354-356	3
α-helix	358-375	18
α-helix	498-522	25
α-helix	524-525	2
α-helix	527-555	29

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

Element	Residues	Length	Sheet
α-helix	11-21	11
β-strand	28	1	2
α-helix	30-40	11
α-helix	46-56	11
β-strand	64	1	2
α-helix	66-74	9
α-helix	80-93	14
α-helix	95-97	3
β-strand	100-102	3	3
α-helix	103-112	10
α-helix	119-129	11
β-strand	136-138	3	3
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	548	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

>7TCI_1 Potassium voltage-gated channel subfamily KQT member 1 (chains A, C, E, G)
MATDPPRPTINLDPRVSIYSGRRPLLSRTNIQGRVYNFLERPTGWKCFVYHFTVFLIVLI
CLIFSVLSTIQQYNNLATETLFWMEIVLVVFFGAEYVVRLWSAGCRSKYVGVWGRLRFAR
KPISVIDLIVVVASVIVLCVGSNGQVFATSAIRGIRFLQILRMLHVDRQGGTWRLLGSVV
FIHRQELITTLYIGFLGLIFSSYFVYLAEKDAIDSSGEYQFGSYADALWWGVVTVTTIGY
GDKVPQTWIGKTIASCFSVFAISFFALPAGILGSGFALKVQQKQRQKHFNRQIPAAASLI
QTAWRCYAAENPDSATWKIYIRKQSRNHHLMSPSPKPKKSAMVKKKKIRTERDEGSTDKM
LNIPHITYDHVADDRKNDGYSVESYENTVRKPFGFLDPSTGPFIRTSSFTDDLDMEGDTL
LTPITHISELKEHHRAAIKVIRRMQYFVAKKKFQQARKPYDVRDVIEQYSQGHLNLMVRI
KELQRRLDQSLGKPSLFLSVSDKVKDKGINTIGSRLNRVEDKVTQMDHKLNLITDMLHHL
LTNQQSNS

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

>7TCI_2 Calmodulin-1 (chains B, D, F, H)
MADQLTEEQIAEFKEAFSLFDKDGDGTITTKELGTVMRSLGQNPTEAELQDMINEVDADG
NGTIDFPEFLTMMARKMKDTDSEEEIREAFRVFDKDGNGYISAAELRHVMTNLGEKLTDE
EVDEMIREADIDGDGQVNYEEFVQMMTAK

Ligands and cofactors

ID	Name	Formula	Copies
I0S	(2R)-N-[4-(4-methoxyphenyl)-1,3-thiazol-2-yl]-1-(4-methylbenzene-1-sulfonyl)pip…	C23 H25 N3 O4 S2	4
CA	Calcium ion	Ca	12

Primary citation

Structural and electrophysiological basis for the modulation of KCNQ1 channel currents by ML277. Willegems, K., Eldstrom, J., Kyriakis, E. et al. Nat Commun (2022) 13:3760-3760. DOI 10.1038/s41467-022-31526-7 · 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
9MY4 3.53 Å, Structure of Xenopus KCNQ1(E150R/R221E)-CaM with the VSD in the intermediate state
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
10NK 3.95 Å, Xenopus KCNQ1 Intermediate State (E1R/R2E) in complex with UCL2077

Browse structure collections

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