9VUB: Channel C complex with 3
channel C complex with 3. Determined by electron microscopy at 3.35 Å resolution. Released 11 Mar 2026.
- Method
- Electron microscopy
- Resolution
- 3.35 Å
- Organism
- Homo sapiens
- Chains
- 8
- Atoms
- 16,807
- Mol. weight
- 352.3 kDa
- Ligands
- POV, CLR, CA, A1B92
- Released
- 11 Mar 2026
Explore 9VUB in 3D
Show helices and sheets
RCSB PDB
PDBe
Secondary structure: helices and β-sheets
9VUB contains 96 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.
Chain A: 15 helices, 2 β-strands
| Element | Residues | Length | Sheet |
|---|
| α-helix | 119-155 | 37 | |
| α-helix | 165-199 | 35 | |
| α-helix | 205-207 | 3 | |
| α-helix | 211-223 | 13 | |
| β-strand | 234-240 | 7 | 10 |
| β-strand | 247-253 | 7 | 10 |
| α-helix | 255-259 | 5 | |
| α-helix | 260-266 | 7 | |
| α-helix | 267-276 | 10 | |
| α-helix | 283-291 | 9 | |
| α-helix | 298-308 | 11 | |
| α-helix | 310-333 | 24 | |
| α-helix | 345-356 | 12 | |
| α-helix | 369-396 | 28 | |
| α-helix | 401-435 | 35 | |
| α-helix | 445-476 | 32 | |
| α-helix | 481-492 | 12 | |
Chain B: 16 helices, 2 β-strands
| Element | Residues | Length | Sheet |
|---|
| α-helix | 119-155 | 37 | |
| α-helix | 165-199 | 35 | |
| α-helix | 205-208 | 4 | |
| α-helix | 211-223 | 13 | |
| β-strand | 234-240 | 7 | 11 |
| β-strand | 247-253 | 7 | 11 |
| α-helix | 255-259 | 5 | |
| α-helix | 260-266 | 7 | |
| α-helix | 267-276 | 10 | |
| α-helix | 278-281 | 4 | |
| α-helix | 283-291 | 9 | |
| α-helix | 298-308 | 11 | |
| α-helix | 310-333 | 24 | |
| α-helix | 345-356 | 12 | |
| α-helix | 369-395 | 27 | |
| α-helix | 401-434 | 34 | |
| α-helix | 435-439 | 5 | |
| α-helix | 445-492 | 48 | |
Chain C: 17 helices, 2 β-strands
| Element | Residues | Length | Sheet |
|---|
| α-helix | 119-155 | 37 | |
| α-helix | 165-199 | 35 | |
| α-helix | 205-207 | 3 | |
| α-helix | 211-225 | 15 | |
| β-strand | 234-240 | 7 | 1 |
| β-strand | 247-253 | 7 | 1 |
| α-helix | 255-259 | 5 | |
| α-helix | 260-266 | 7 | |
| α-helix | 267-276 | 10 | |
| α-helix | 278-281 | 4 | |
| α-helix | 283-291 | 9 | |
| α-helix | 298-308 | 11 | |
| α-helix | 310-333 | 24 | |
| α-helix | 345-356 | 12 | |
| α-helix | 369-397 | 29 | |
| α-helix | 399-400 | 2 | |
| α-helix | 401-434 | 34 | |
| α-helix | 435-439 | 5 | |
| α-helix | 445-492 | 48 | |
Chain D: 16 helices, 2 β-strands
| Element | Residues | Length | Sheet |
|---|
| α-helix | 119-155 | 37 | |
| α-helix | 165-199 | 35 | |
| α-helix | 205-207 | 3 | |
| α-helix | 211-223 | 13 | |
| β-strand | 234-240 | 7 | 12 |
| β-strand | 247-253 | 7 | 12 |
| α-helix | 255-259 | 5 | |
| α-helix | 260-266 | 7 | |
| α-helix | 267-276 | 10 | |
| α-helix | 283-291 | 9 | |
| α-helix | 298-308 | 11 | |
| α-helix | 310-333 | 24 | |
| α-helix | 345-356 | 12 | |
| α-helix | 369-396 | 28 | |
| α-helix | 401-434 | 34 | |
| α-helix | 435-439 | 5 | |
| α-helix | 445-476 | 32 | |
| α-helix | 481-492 | 12 | |
Chain E: 8 helices, 4 β-strands
| Element | Residues | Length | Sheet |
|---|
| α-helix | 6-19 | 14 | |
| β-strand | 27 | 1 | 6 |
| α-helix | 29-39 | 11 | |
| α-helix | 45-53 | 9 | |
| β-strand | 63 | 1 | 6 |
| α-helix | 65-76 | 12 | |
| α-helix | 83-92 | 10 | |
| β-strand | 99-101 | 3 | 7 |
| α-helix | 102-111 | 10 | |
| α-helix | 118-128 | 11 | |
| β-strand | 135-137 | 3 | 7 |
| α-helix | 138-146 | 9 | |
Chain F: 8 helices, 4 β-strands
| Element | Residues | Length | Sheet |
|---|
| α-helix | 6-19 | 14 | |
| β-strand | 27 | 1 | 8 |
| α-helix | 29-38 | 10 | |
| α-helix | 45-55 | 11 | |
| β-strand | 63 | 1 | 8 |
| α-helix | 65-76 | 12 | |
| α-helix | 83-91 | 9 | |
| β-strand | 99-101 | 3 | 9 |
| α-helix | 102-111 | 10 | |
| α-helix | 118-128 | 11 | |
| β-strand | 135-137 | 3 | 9 |
| α-helix | 138-146 | 9 | |
Chain G: 8 helices, 4 β-strands
| Element | Residues | Length | Sheet |
|---|
| α-helix | 7-19 | 13 | |
| β-strand | 27 | 1 | 2 |
| α-helix | 29-39 | 11 | |
| α-helix | 45-55 | 11 | |
| β-strand | 63 | 1 | 2 |
| α-helix | 65-76 | 12 | |
| α-helix | 82-91 | 10 | |
| β-strand | 99-101 | 3 | 3 |
| α-helix | 102-111 | 10 | |
| α-helix | 118-128 | 11 | |
| β-strand | 135-137 | 3 | 3 |
| α-helix | 138-146 | 9 | |
Chain H: 8 helices, 4 β-strands
| Element | Residues | Length | Sheet |
|---|
| α-helix | 6-19 | 14 | |
| β-strand | 27 | 1 | 4 |
| α-helix | 29-39 | 11 | |
| α-helix | 45-55 | 11 | |
| β-strand | 63 | 1 | 4 |
| α-helix | 65-76 | 12 | |
| α-helix | 83-91 | 9 | |
| β-strand | 99-101 | 3 | 5 |
| α-helix | 102-111 | 10 | |
| α-helix | 118-128 | 11 | |
| β-strand | 135-137 | 3 | 5 |
| α-helix | 138-146 | 9 | |
Molecules and chains
| Molecule | Chains | Type | Length | Organism | UniProt |
|---|
| Small conductance calcium-activated potassium channel protein 2 | A, B, C, D | protein | 579 | Homo sapiens | Q9H2S1 (AlphaFold model) |
| Calmodulin-1 | E, F, G, H | protein | 149 | Homo sapiens | P0DP23 (AlphaFold model) |
Sequence of entity 1 (A, B, C, D), FASTA
>9VUB_1 Small conductance calcium-activated potassium channel protein 2 (chains A, B, C, D)
MSSCRYNGGVMRPLSNLSASRRNLHEMDSEAQPLQPPASVGGGGGASSPSAAAAAAAAVS
SSAPEIVVSKPEHNNSNNLALYGTGGGGSTGGGGGGGGSGHGSSSGTKSSKKKNQNIGYK
LGHRRALFEKRKRLSDYALIFGMFGIVVMVIETELSWGAYDKASLYSLALKCLISLSTII
LLGLIIVYHAREIQLFMVDNGADDWRIAMTYERIFFICLEILVCAIHPIPGNYTFTWTAR
LAFSYAPSTTTADVDIILSIPMFLRLYLIARVMLLHSKLFTDASSRSIGALNKINFNTRF
VMKTLMTICPGTVLLVFSISLWIIAAWTVRACERYHDQQDVTSNFLGAMWLISITFLSIG
YGDMVPNTYCGKGVCLLTGIMGAGCTALVVAVVARKLELTKAEKHVHNFMMDTQLTKRVK
NAAANVLRETWLIYKNTKLVKKIDHAKVRKHQRKFLQAIHQLRSVKMEQRKLNDQANTLV
DLAKTQNIMYDMISDLNERSEDFEKRIVTLETKLETLIGSIHALPGLISQTIRQQQRDFI
EAQMESYDKHVTYNAERSRSSSRRRRSSSTAPPTSSESS
Sequence of entity 2 (E, F, G, H), FASTA
>9VUB_2 Calmodulin-1 (chains E, F, G, H)
MADQLTEEQIAEFKEAFSLFDKDGDGTITTKELGTVMRSLGQNPTEAELQDMINEVDADG
NGTIDFPEFLTMMARKMKDTDSEEEIREAFRVFDKDGNGYISAAELRHVMTNLGEKLTDE
EVDEMIREADIDGDGQVNYEEFVQMMTAK
Ligands and cofactors
| ID | Name | Formula | Copies |
|---|
| POV | (2S)-3-(hexadecanoyloxy)-2-[(9Z)-octadec-9-enoyloxy]propyl… | C42 H82 N O8 P | 32 |
| CLR | Cholesterol | C27 H46 O | 8 |
| CA | Calcium ion | Ca | 12 |
| A1B92 | Rimtuzalcap | C18 H24 F2 N6 O | 4 |
Water and common crystallization additives (K) are not listed.
Primary citation
Structural mechanisms for inhibition and activation of human small-conductance Ca 2+ -activated potassium channel SK2. Ma, B., Wu, D., Cao, E. et al. Nat Commun (2026) 17:1770-1770. DOI 10.1038/s41467-026-68475-4 · PubMed
Other PDB entries of the same protein (UniProt Q9H2S1 (AlphaFold model), which also has an AlphaFold model), best resolution first:
- 5V03 1.58 Å, A positive allosteric modulator binding pocket in SK2 ion channels is shared by Riluzole…
- 5V02 1.78 Å, A positive allosteric modulator binding pocket in SK2 ion channels is shared by Riluzole…
- 5WBX 1.9 Å, Structural insights into the potency of SK/IK channel positive modulators
- 5WC5 2.3 Å, Structural insights into the potency of SK/IK channel positive modulators
- 6ALE 2.5 Å, A V-to-F substitution in SK2 channels causes Ca2+ hypersensitivity and improves…
- 9ZRQ 2.77 Å, Cryo-EM structure of KCa2.2/calmodulin channel in complex with SKA31.
- 9VUC 2.96 Å, channel B complex with 2
- 9O48 3.1 Å, Cryo-EM structure of the human SK2-4 chimera/calmodulin channel complex in the Ca2+…
- 9O5O 3.1 Å, Cryo-EM structure of the human SK2-4 chimera/calmodulin channel complex bound to a small…
- 9O52 3.18 Å, Cryo-EM structure of the human SK2-4 chimera/calmodulin channel complex bound to the bee…
- 9VUA 3.23 Å, channel A complex with 1
- 9O53 3.3 Å, Cryo-EM structure of the human SK2-4 chimera/calmodulin channel complex bound to a small…
Browse structure collections
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