6CNO: PDB entry 6CNO

Cryo-EM structure of the human SK4/calmodulin channel complex in the Ca2+ bound state II. Determined by electron microscopy at 4.7 Å resolution. Released 2 May 2018.

Method: Electron microscopy
Resolution: 4.7 Å
Organism: Homo sapiens
Chains: 8
Atoms: 15,428
Mol. weight: 258.93 kDa
Ligands: CA
Released: 2 May 2018

Explore 6CNO in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

6CNO contains 96 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.

Chains A, B, C and D: 16 helices, 0 β-strands

Element	Residues	Length
α-helix	10-50	41
α-helix	55-89	35
α-helix	96-99	4
α-helix	102-114	13
α-helix	148-154	7
α-helix	155-162	8
α-helix	163-170	8
α-helix	177-186	10
α-helix	192-202	11
α-helix	204-226	23
α-helix	237-248	12
α-helix	261-287	27
α-helix	291-292	2
α-helix	293-330	38
α-helix	334-368	35
α-helix	371-385	15

Chains E, F, G and H: 8 helices, 4 β-strands

Element	Residues	Length	Sheet
α-helix	6-17	12
β-strand	27	1	1
α-helix	29-38	10
α-helix	45-55	11
β-strand	63	1	1
α-helix	65-76	12
α-helix	81-92	12
β-strand	100	1	2
α-helix	102-109	8
α-helix	118-128	11
β-strand	136	1	2
α-helix	138-145	8

Molecules and chains

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)

Sequence of entity 1 (A, B, C, D), FASTA

>6CNO_1 Intermediate conductance calcium-activated potassium channel protein 4 (chains A, B, C, D)
MGGDLVLGLGALRRRKRLLEQEKSLAGWALVLAGTGIGLMVLHAEMLWFGGCSWALYLFL
VKCTISISTFLLLCLIVAFHAKEVQLFMTDNGLRDWRVALTGRQAAQIVLELVVCGLHPA
PVRGPPCVQDLGAPLTSPQPWPGFLGQGEALLSLAMLLRLYLVPRAVLLRSGVLLNASYR
SIGALNQVRFRHWFVAKLYMNTHPGRLLLGLTLGLWLTTAWVLSVAERQAVNATGHLSDT
LWLIPITFLTIGYGDVVPGTMWGKIVCLCTGVMGVCCTALLVAVVARKLEFNKAEKHVHN
FMMDIQYTKEMKESAARVLQEAWMFYKHTRRKESHAARRHQRKLLAAINAFRQVRLKHRK
LREQVNSMVDISKMHMILYDLQQNLSSSHRALEKQIDTLAGKLDALTELLSTALGPRQLP
EPSQQSK

Sequence of entity 2 (E, F, G, H), FASTA

>6CNO_2 Calmodulin-1 (chains E, F, G, H)
MADQLTEEQIAEFKEAFSLFDKDGDGTITTKELGTVMRSLGQNPTEAELQDMINEVDADG
NGTIDFPEFLTMMARKMKDTDSEEEIREAFRVFDKDGNGYISAAELRHVMTNLGEKLTDE
EVDEMIREADIDGDGQVNYEEFVQMMTAK

Ligands and cofactors

ID	Name	Formula	Copies
CA	Calcium ion	Ca	12

Primary citation

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:

6D42 1.75 Å, Crystal structure of the KCa3.1 C-terminal four-helix bundle (with copper)
9ZRK 2.99 Å, Cryo-EM structure of KCa3.1_I/calmodulin channel in complex with SKA111.
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…
9O53 3.3 Å, Cryo-EM structure of the human SK2-4 chimera/calmodulin channel complex bound to a small…
9ZRL 3.38 Å, Cryo-EM structure of KCa3.1_II/calmodulin channel in complex with SKA111.
9ZPT 3.39 Å, Cryo-EM structure of KCa3.1_II/calmodulin channel in complex with SKA31.
6CNM 3.4 Å, Cryo-EM structure of the human SK4/calmodulin channel complex
9O51 3.4 Å, Cryo-EM structure of the human SK2-4 chimera/calmodulin channel complex in the Ca2+ free…
9YDZ 3.4 Å, Cryo EM structure of KCa3.1_R355K_II/calmodulin channel in complex with rimtuzalcap
6CNN 3.5 Å, Cryo-EM structure of the human SK4/calmodulin channel complex in the Ca2+ bound state I

Browse structure collections

About this viewer

MolViewer shows 6CNO directly in your browser with nothing to install. Switch between cartoon, ball-and-stick, spacefill and surface views, color by chain, secondary structure or B-factor, measure distances, angles and dihedrals, and share or embed the view.