Cryo-EM structure of the human SK4/calmodulin channel complex in the Ca2+ bound state I. Determined by electron microscopy at 3.5 Å resolution. Released 2 May 2018.
Explore 6CNN in 3D Show helices and sheets RCSB PDB PDBe
6CNN contains 100 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.
| Element | Residues | Length | Sheet |
|---|---|---|---|
| α-helix | 10-48 | 39 | |
| α-helix | 55-90 | 36 | |
| α-helix | 96-99 | 4 | |
| α-helix | 102-114 | 13 | |
| α-helix | 153-158 | 6 | |
| α-helix | 162-170 | 9 | |
| α-helix | 172-174 | 3 | |
| α-helix | 177-186 | 10 | |
| α-helix | 192-202 | 11 | |
| α-helix | 204-226 | 23 | |
| α-helix | 237-248 | 12 | |
| α-helix | 261-288 | 28 | |
| α-helix | 291-292 | 2 | |
| α-helix | 293-331 | 39 | |
| α-helix | 334-368 | 35 | |
| α-helix | 370-381 | 12 | |
| α-helix | 382-384 | 3 |
| Element | Residues | Length | Sheet |
|---|---|---|---|
| α-helix | 6-16 | 11 | |
| β-strand | 27 | 1 | 1 |
| α-helix | 29-38 | 10 | |
| α-helix | 45-53 | 9 | |
| β-strand | 63 | 1 | 1 |
| α-helix | 65-74 | 10 | |
| α-helix | 83-92 | 10 | |
| β-strand | 100 | 1 | 2 |
| α-helix | 102-111 | 10 | |
| α-helix | 120-128 | 9 | |
| β-strand | 136 | 1 | 2 |
| α-helix | 139-145 | 7 |
| Element | Residues | Length | Sheet |
|---|---|---|---|
| α-helix | 6-16 | 11 | |
| β-strand | 27 | 1 | 3 |
| α-helix | 29-38 | 10 | |
| α-helix | 45-53 | 9 | |
| β-strand | 63 | 1 | 3 |
| α-helix | 65-74 | 10 | |
| α-helix | 83-92 | 10 | |
| β-strand | 100 | 1 | 4 |
| α-helix | 102-111 | 10 | |
| α-helix | 119-128 | 10 | |
| β-strand | 136 | 1 | 4 |
| α-helix | 139-145 | 7 |
| Molecule | Chains | Type | Length | Organism | UniProt |
|---|---|---|---|---|---|
| Intermediate conductance calcium-activated potassium channel protein 4 | A, B, C, D | protein | 427 | Homo sapiens | O15554 (AlphaFold model) |
| Calmodulin-1 | E, F, G, H | protein | 149 | Homo sapiens | P0DP23 (AlphaFold model) |
>6CNN_1 Intermediate conductance calcium-activated potassium channel protein 4 (chains A, B, C, D) MGGDLVLGLGALRRRKRLLEQEKSLAGWALVLAGTGIGLMVLHAEMLWFGGCSWALYLFL VKCTISISTFLLLCLIVAFHAKEVQLFMTDNGLRDWRVALTGRQAAQIVLELVVCGLHPA PVRGPPCVQDLGAPLTSPQPWPGFLGQGEALLSLAMLLRLYLVPRAVLLRSGVLLNASYR SIGALNQVRFRHWFVAKLYMNTHPGRLLLGLTLGLWLTTAWVLSVAERQAVNATGHLSDT LWLIPITFLTIGYGDVVPGTMWGKIVCLCTGVMGVCCTALLVAVVARKLEFNKAEKHVHN FMMDIQYTKEMKESAARVLQEAWMFYKHTRRKESHAARRHQRKLLAAINAFRQVRLKHRK LREQVNSMVDISKMHMILYDLQQNLSSSHRALEKQIDTLAGKLDALTELLSTALGPRQLP EPSQQSK
>6CNN_2 Calmodulin-1 (chains E, F, G, H) MADQLTEEQIAEFKEAFSLFDKDGDGTITTKELGTVMRSLGQNPTEAELQDMINEVDADG NGTIDFPEFLTMMARKMKDTDSEEEIREAFRVFDKDGNGYISAAELRHVMTNLGEKLTDE EVDEMIREADIDGDGQVNYEEFVQMMTAK
| ID | Name | Formula | Copies |
|---|---|---|---|
| CA | Calcium ion | Ca | 12 |
| LMT | Dodecyl-beta-D-maltoside | C24 H46 O11 | 8 |
| POV | (2S)-3-(hexadecanoyloxy)-2-[(9Z)-octadec-9-enoyloxy]propyl… | C42 H82 N O8 P | 4 |
Water and common crystallization additives (K) are not listed.
Activation mechanism of a human SK-calmodulin channel complex elucidated by cryo-EM structures. Lee, C.H., MacKinnon, R. Science (2018) 360:508-513. DOI 10.1126/science.aas9466 · 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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