8V2H: KCa2.2 channel

Cryo-EM structure of the KCa2.2 channel bound to inhibitor AP14145. Determined by electron microscopy at 3.1 Å resolution. Released 23 Apr 2025.

Method: Electron microscopy
Resolution: 3.1 Å
Organism: Rattus norvegicus
Chains: 8
Atoms: 16,168
Mol. weight: 231.02 kDa
Ligands: CA
Released: 23 Apr 2025

Explore 8V2H in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

8V2H contains 95 α-helices and 22 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	123-159	37
α-helix	166-201	36
α-helix	206-209	4
α-helix	213-225	13
β-strand	235-241	7	1
β-strand	248-254	7	1
α-helix	256-260	5
α-helix	261-267	7
α-helix	268-276	9
α-helix	279-281	3
α-helix	286-293	8
α-helix	301-309	9
α-helix	314-334	21
α-helix	346-357	12
α-helix	370-396	27
α-helix	402-438	37
α-helix	446-477	32

Chain B: 15 helices, 2 β-strands

Element	Residues	Length	Sheet
α-helix	124-159	36
α-helix	166-200	35
α-helix	206-208	3
α-helix	214-225	12
β-strand	235-241	7	4
β-strand	248-254	7	4
α-helix	256-260	5
α-helix	261-267	7
α-helix	268-276	9
α-helix	279-281	3
α-helix	284-293	10
α-helix	301-309	9
α-helix	314-334	21
α-helix	346-357	12
α-helix	370-396	27
α-helix	402-438	37
α-helix	446-477	32

Chain C: 15 helices, 2 β-strands

Element	Residues	Length	Sheet
α-helix	119-159	41
α-helix	166-200	35
α-helix	206-209	4
α-helix	214-225	12
β-strand	235-241	7	7
β-strand	248-254	7	7
α-helix	256-260	5
α-helix	261-267	7
α-helix	268-276	9
α-helix	279-281	3
α-helix	285-293	9
α-helix	301-309	9
α-helix	314-334	21
α-helix	346-357	12
α-helix	370-396	27
α-helix	402-438	37
α-helix	446-476	31

Chain D: 16 helices, 2 β-strands

Element	Residues	Length	Sheet
α-helix	119-123	5
α-helix	124-159	36
α-helix	166-200	35
α-helix	206-209	4
α-helix	214-225	12
β-strand	235-241	7	10
β-strand	248-254	7	10
α-helix	256-260	5
α-helix	261-267	7
α-helix	268-276	9
α-helix	279-281	3
α-helix	284-293	10
α-helix	301-309	9
α-helix	314-334	21
α-helix	346-357	12
α-helix	370-397	28
α-helix	402-438	37
α-helix	446-477	32

Chain E: 8 helices, 4 β-strands

Element	Residues	Length	Sheet
α-helix	6-17	12
β-strand	27	1	2
α-helix	32-38	7
α-helix	45-54	10
β-strand	63	1	2
α-helix	65-76	12
α-helix	81-91	11
β-strand	100-101	2	3
α-helix	102-111	10
α-helix	118-128	11
β-strand	135-136	2	3
α-helix	139-144	6

Chain F: 9 helices, 4 β-strands

Element	Residues	Length	Sheet
α-helix	6-17	12
β-strand	27	1	5
α-helix	29-38	10
α-helix	45-54	10
β-strand	63	1	5
α-helix	65-75	11
α-helix	81-83	3
α-helix	84-91	8
β-strand	100-101	2	6
α-helix	102-111	10
α-helix	118-125	8
β-strand	135-136	2	6
α-helix	139-144	6

Chain G: 8 helices, 4 β-strands

Element	Residues	Length	Sheet
α-helix	6-19	14
β-strand	27	1	8
α-helix	29-37	9
α-helix	45-54	10
β-strand	63	1	8
α-helix	65-76	12
α-helix	84-90	7
β-strand	100-101	2	9
α-helix	102-110	9
α-helix	118-128	11
β-strand	135-136	2	9
α-helix	139-144	6

Chain H: 9 helices, 2 β-strands

Element	Residues	Length	Sheet
α-helix	6-16	11
α-helix	17-19	3
α-helix	29-37	9
α-helix	45-54	10
α-helix	65-76	12
α-helix	84-91	8
β-strand	100-101	2	11
α-helix	104-110	7
α-helix	118-128	11
β-strand	135-136	2	11
α-helix	139-144	6

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Small conductance calcium-activated potassium channel protein 2	A, B, C, D	protein	361	Rattus norvegicus	P70604 (AlphaFold model)
Calmodulin-1	E, F, G, H	protein	146	Rattus norvegicus	P0DP29 (AlphaFold model)

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

>8V2H_1 Small conductance calcium-activated potassium channel protein 2 (chains A, B, C, D)
IGYKLGHRRALFEKRKRLSDYALIFGMFGIVVMVIETELSWGAYDKASLYSLALKCLISL
STIILLGLIIVYHAREIQLFMVDNGADDWRIAMTYERIFFICLEILVCAIHPIPGNYTFT
WTARLAFSYAPSTTTADVDIILSIPMFLRLYLIARVMLLHSKLFTDASSRSIGALNKINF
NTRFVMKTLMTICPGTVLLVFSISLWIIAAWTVRACERYHDQQDVTSNFLGAMWLISITF
LSIGYGDMVPNTYCGKGVCLLTGIMGAGCTALVVAVVARKLELTKAEKHVHNFMMDTQLT
KRVKNAAANVLRETWLIYKNTKLVKKIDHAKVRKHQRKFLQAIHQLRSVKMEQRKLNDQA
N

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

>8V2H_2 Calmodulin-1 (chains E, F, G, H)
DQLTEEQIAEFKEAFSLFDKDGDGTITTKELGTVMRSLGQNPTEAELQDMINEVDADGNG
TIDFPEFLTMMARKMKDTDSEEEIREAFRVFDKDGNGYISAAELRHVMTNLGEKLTDEEV
DEMIREADIDGDGQVNYEEFVQMMTA

Ligands and cofactors

ID	Name	Formula	Copies
CA	Calcium ion	Ca	8

Water and common crystallization additives (K) are not listed.

Primary citation

Cryo-EM structures of the small-conductance Ca 2+ -activated K Ca 2.2 channel. Nam, Y.W., Im, D., Garcia, A.S.C. et al. Nat Commun (2025) 16:3690-3690. DOI 10.1038/s41467-025-59061-1 · PubMed

Other PDB entries of the same protein (UniProt P70604 (AlphaFold model), which also has an AlphaFold model), best resolution first:

4J9Y 1.51 Å, Calcium-calmodulin complexed with the calmodulin binding domain from a small conductance…
1G4Y 1.6 Å, 1.60 a crystal structure of the gating domain from small conductance potassium channel…
4G28 1.63 Å, Calcium-calmodulin complexed with the calmodulin binding domain from a small conductance…
4G27 1.65 Å, Calcium-calmodulin complexed with the calmodulin binding domain from a small conductance…
4J9Z 1.66 Å, Calcium-calmodulin complexed with the calmodulin binding domain from a small conductance…
3SJQ 1.9 Å, Crystal structure of a small conductance potassium channel splice variant complexed with…
4QNH 2.02 Å, Calcium-calmodulin (T79D) complexed with the calmodulin binding domain from a small…
2PNV 2.1 Å, Crystal Structure of the leucine zipper domain of small-conductance Ca2+-activated K+…
6CZQ 2.2 Å, A V-to-F substitution in SK2 channels causes Ca2+ hypersensitivity and improves…
9O7S 2.71 Å, Cryo-EM structure of KCa2.2/calmodulin channel in complex with NS309
9O93 2.96 Å, Cryo-EM structure of KCa2.2_II/calmodulin channel in complex with rimtuzalcap
1QX7 3.09 Å, Crystal structure of apoCaM bound to the gating domain of small conductance…

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