9VUC: Channel B complex with 2
channel B complex with 2. Determined by electron microscopy at 2.96 Å resolution. Released 11 Mar 2026.
- Method
- Electron microscopy
- Resolution
- 2.96 Å
- Organism
- Homo sapiens
- Chains
- 7
- Atoms
- 12,472
- Mol. weight
- 306.58 kDa
- Ligands
- Y7Z
- Released
- 11 Mar 2026
Explore 9VUC in 3D
Show helices and sheets
RCSB PDB
PDBe
Secondary structure: helices and β-sheets
9VUC contains 87 α-helices and 8 β-strands across 7 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: 18 helices, 2 β-strands
| Element | Residues | Length | Sheet |
|---|
| α-helix | 119-156 | 38 | |
| α-helix | 165-199 | 35 | |
| α-helix | 205-207 | 3 | |
| α-helix | 211-223 | 13 | |
| α-helix | 228-229 | 2 | |
| β-strand | 235-240 | 6 | 1 |
| β-strand | 247-252 | 6 | 1 |
| α-helix | 255-259 | 5 | |
| α-helix | 260-266 | 7 | |
| α-helix | 267-275 | 9 | |
| α-helix | 278-281 | 4 | |
| α-helix | 283-291 | 9 | |
| α-helix | 298-308 | 11 | |
| α-helix | 310-333 | 24 | |
| α-helix | 334-336 | 3 | |
| α-helix | 345-356 | 12 | |
| α-helix | 369-396 | 28 | |
| α-helix | 398-400 | 3 | |
| α-helix | 401-437 | 37 | |
| α-helix | 445-472 | 28 | |
Chain B: 19 helices, 2 β-strands
| Element | Residues | Length | Sheet |
|---|
| α-helix | 119-156 | 38 | |
| α-helix | 165-199 | 35 | |
| α-helix | 205-207 | 3 | |
| α-helix | 211-223 | 13 | |
| α-helix | 228-229 | 2 | |
| β-strand | 235-240 | 6 | 2 |
| β-strand | 247-252 | 6 | 2 |
| α-helix | 255-259 | 5 | |
| α-helix | 260-266 | 7 | |
| α-helix | 267-275 | 9 | |
| α-helix | 278-281 | 4 | |
| α-helix | 283-292 | 10 | |
| α-helix | 298-308 | 11 | |
| α-helix | 310-333 | 24 | |
| α-helix | 334-336 | 3 | |
| α-helix | 345-356 | 12 | |
| α-helix | 369-396 | 28 | |
| α-helix | 398-400 | 3 | |
| α-helix | 401-434 | 34 | |
| α-helix | 435-439 | 5 | |
| α-helix | 445-467 | 23 | |
Chain C: 16 helices, 2 β-strands
| Element | Residues | Length | Sheet |
|---|
| α-helix | 119-156 | 38 | |
| α-helix | 165-199 | 35 | |
| α-helix | 205-207 | 3 | |
| α-helix | 211-223 | 13 | |
| β-strand | 234-240 | 7 | 3 |
| β-strand | 247-253 | 7 | 3 |
| α-helix | 255-259 | 5 | |
| α-helix | 260-266 | 7 | |
| α-helix | 267-276 | 10 | |
| α-helix | 283-292 | 10 | |
| α-helix | 298-308 | 11 | |
| α-helix | 310-333 | 24 | |
| α-helix | 345-356 | 12 | |
| α-helix | 369-396 | 28 | |
| α-helix | 398-400 | 3 | |
| α-helix | 401-434 | 34 | |
| α-helix | 435-439 | 5 | |
| α-helix | 445-470 | 26 | |
Chain D: 19 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 | |
| α-helix | 228-229 | 2 | |
| β-strand | 234-240 | 7 | 4 |
| β-strand | 247-253 | 7 | 4 |
| α-helix | 255-259 | 5 | |
| α-helix | 260-267 | 8 | |
| α-helix | 268-276 | 9 | |
| α-helix | 278-281 | 4 | |
| α-helix | 283-292 | 10 | |
| α-helix | 298-308 | 11 | |
| α-helix | 310-333 | 24 | |
| α-helix | 334-336 | 3 | |
| α-helix | 345-356 | 12 | |
| α-helix | 369-396 | 28 | |
| α-helix | 398-400 | 3 | |
| α-helix | 401-434 | 34 | |
| α-helix | 435-439 | 5 | |
| α-helix | 445-472 | 28 | |
Chain E: 5 helices, 0 β-strands
| Element | Residues | Length | Sheet |
|---|
| α-helix | 83-90 | 8 | |
| α-helix | 102-106 | 5 | |
| α-helix | 107-111 | 5 | |
| α-helix | 118-128 | 11 | |
| α-helix | 138-144 | 7 | |
Chain F: 5 helices, 0 β-strands
| Element | Residues | Length | Sheet |
|---|
| α-helix | 83-90 | 8 | |
| α-helix | 102-106 | 5 | |
| α-helix | 107-111 | 5 | |
| α-helix | 118-128 | 11 | |
| α-helix | 138-145 | 8 | |
Chain G: 5 helices, 0 β-strands
| Element | Residues | Length | Sheet |
|---|
| α-helix | 83-87 | 5 | |
| α-helix | 102-106 | 5 | |
| α-helix | 107-111 | 5 | |
| α-helix | 118-128 | 11 | |
| α-helix | 138-145 | 8 | |
Molecules and chains
| Molecule | Chains | Type | Length | Organism | UniProt |
|---|
| Calmodulin-1 | E, F, G | protein | 149 | Homo sapiens | P0DP23 (AlphaFold model) |
| Small conductance calcium-activated potassium channel protein 2 | A, B, C, D | protein | 579 | Homo sapiens | Q9H2S1 (AlphaFold model) |
Sequence of entity 1 (E, F, G), FASTA
>9VUC_1 Calmodulin-1 (chains E, F, G)
MADQLTEEQIAEFKEAFSLFDKDGDGTITTKELGTVMRSLGQNPTEAELQDMINEVDADG
NGTIDFPEFLTMMARKMKDTDSEEEIREAFRVFDKDGNGYISAAELRHVMTNLGEKLTDE
EVDEMIREADIDGDGQVNYEEFVQMMTAK
Sequence of entity 2 (A, B, C, D), FASTA
>9VUC_2 Small conductance calcium-activated potassium channel protein 2 (chains A, B, C, D)
MSSCRYNGGVMRPLSNLSASRRNLHEMDSEAQPLQPPASVGGGGGASSPSAAAAAAAAVS
SSAPEIVVSKPEHNNSNNLALYGTGGGGSTGGGGGGGGSGHGSSSGTKSSKKKNQNIGYK
LGHRRALFEKRKRLSDYALIFGMFGIVVMVIETELSWGAYDKASLYSLALKCLISLSTII
LLGLIIVYHAREIQLFMVDNGADDWRIAMTYERIFFICLEILVCAIHPIPGNYTFTWTAR
LAFSYAPSTTTADVDIILSIPMFLRLYLIARVMLLHSKLFTDASSRSIGALNKINFNTRF
VMKTLMTICPGTVLLVFSISLWIIAAWTVRACERYHDQQDVTSNFLGAMWLISITFLSIG
YGDMVPNTYCGKGVCLLTGIMGAGCTALVVAVVARKLELTKAEKHVHNFMMDTQLTKRVK
NAAANVLRETWLIYKNTKLVKKIDHAKVRKHQRKFLQAIHQLRSVKMEQRKLNDQANTLV
DLAKTQNIMYDMISDLNERSEDFEKRIVTLETKLETLIGSIHALPGLISQTIRQQQRDFI
EAQMESYDKHVTYNAERSRSSSRRRRSSSTAPPTSSESS
Ligands and cofactors
| ID | Name | Formula | Copies |
|---|
| Y7Z | UCL1684 | C34 H30 N4 | 1 |
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 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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