9YDZ: PDB entry 9YDZ

Cryo EM structure of KCa3.1_R355K_II/calmodulin channel in complex with rimtuzalcap. Determined by electron microscopy at 3.4 Å resolution. Released 1 Oct 2025.

Method
Electron microscopy
Resolution
3.4 Å
Organism
Homo sapiens
Chains
8
Atoms
12,219
Mol. weight
191.82 kDa
Released
1 Oct 2025

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

Secondary structure: helices and β-sheets

9YDZ contains 85 α-helices and 0 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.

Chain A: 17 helices, 0 β-strands

ElementResiduesLengthSheet
α-helix10-5041
α-helix56-7217
α-helix76-9116
α-helix96-994
α-helix102-11514
α-helix150-1545
α-helix155-1617
α-helix162-1698
α-helix177-1859
α-helix192-20211
α-helix204-21411
α-helix218-2269
α-helix237-2437
α-helix245-2484
α-helix272-28817
α-helix293-33139
α-helix335-36531
Chain B: 15 helices, 0 β-strands
ElementResiduesLengthSheet
α-helix10-5041
α-helix56-9136
α-helix102-11413
α-helix147-1548
α-helix155-1628
α-helix163-1719
α-helix177-18610
α-helix192-20211
α-helix206-21510
α-helix220-2267
α-helix237-2437
α-helix245-2484
α-helix272-28817
α-helix293-33139
α-helix338-36528
Chain C: 18 helices, 0 β-strands
ElementResiduesLengthSheet
α-helix11-4939
α-helix51-533
α-helix56-9035
α-helix96-994
α-helix102-11514
α-helix150-1545
α-helix155-1617
α-helix162-1698
α-helix177-18610
α-helix192-20211
α-helix206-21813
α-helix222-2265
α-helix237-2437
α-helix245-2484
α-helix261-2699
α-helix275-28814
α-helix293-33139
α-helix335-36531
Chain D: 19 helices, 0 β-strands
ElementResiduesLengthSheet
α-helix11-3222
α-helix34-4512
α-helix46-505
α-helix55-7218
α-helix77-9115
α-helix102-11413
α-helix147-1548
α-helix155-1617
α-helix162-1709
α-helix177-1837
α-helix192-20211
α-helix206-2149
α-helix218-2269
α-helix237-2437
α-helix245-2484
α-helix261-2644
α-helix269-28820
α-helix293-33139
α-helix336-36530
Chains E, F, G and H: 4 helices, 0 β-strands
ElementResiduesLengthSheet
α-helix85-917
α-helix102-11110
α-helix118-12811
α-helix143-1464

Molecules and chains

MoleculeChainsTypeLengthOrganismUniProt
Intermediate conductance calcium-activated potassium channel protein 4A, B, C, Dprotein358Homo sapiensO15554 (AlphaFold model)
Calmodulin-1E, F, G, Hprotein67Homo sapiensP0DP23 (AlphaFold model)
Sequence of entity 1 (A, B, C, D), FASTA
>9YDZ_1 Intermediate conductance calcium-activated potassium channel protein 4 (chains A, B, C, D)
LGALRRRKRLLEQEKSLAGWALVLAGTGIGLMVLHAEMLWFGGCSWALYLFLVKCTISIS
TFLLLCLIVAFHAKEVQLFMTDNGLRDWRVALTGRQAAQIVLELVVCGLHPAPVRGPPCV
QDLGAPLTSPQPWPGFLGQGEALLSLAMLLRLYLVPRAVLLRSGVLLNASYRSIGALNQV
RFRHWFVAKLYMNTHPGRLLLGLTLGLWLTTAWVLSVAERQAVNATGHLSDTLWLIPITF
LTIGYGDVVPGTMWGKIVCLCTGVMGVCCTALLVAVVARKLEFNKAEKHVHNFMMDIQYT
KEMKESAARVLQEAWMFYKHTRRKESHAARRHQRKLLAAINAFRQVKLKHRKLREQVN
Sequence of entity 2 (E, F, G, H), FASTA
>9YDZ_2 Calmodulin-1 (chains E, F, G, H)
SEEEIREAFRVFDKDGNGYISAAELRHVMTNLGEKLTDEEVDEMIREADIDGDGQVNYEE
FVQMMTA

Primary citation

Structural basis for the subtype-selectivity of K Ca 2.2 channel activators. Nam, Y.W., Ramanishka, A., Xu, Y. et al. Nat Commun (2026) 17:531-531. DOI 10.1038/s41467-025-67232-3 · PubMed

Other PDB entries of the same protein (UniProt O15554 (AlphaFold model), which also has an AlphaFold model), best resolution first:

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