4G28: Calcium-calmodulin

Calcium-calmodulin complexed with the calmodulin binding domain from a small conductance potassium channel splice variant and EBIO-1. Determined by X-ray diffraction at 1.63 Å resolution. Released 12 Sept 2012.

Method: X-ray diffraction
Resolution: 1.63 Å
Organism: Rattus norvegicus
Chains: 2
Atoms: 2,164
Mol. weight: 29.72 kDa
Ligands: 0W8, CA
Released: 12 Sept 2012

Explore 4G28 in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

4G28 contains 12 α-helices and 6 β-strands across 2 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 B: 4 helices, 1 β-strand

Element	Residues	Length	Sheet
β-strand	400-401	2	1
α-helix	402-403	2
α-helix	415-439	25
α-helix	446-485	40
α-helix	486-488	3

Chain R: 8 helices, 5 β-strands

Element	Residues	Length	Sheet
α-helix	6-19	14
β-strand	27	1	2
α-helix	29-38	10
α-helix	45-55	11
β-strand	63	1	2
α-helix	65-73	9
β-strand	78-79	2	1
α-helix	82-90	9
β-strand	99-101	3	3
α-helix	102-109	8
α-helix	118-128	11
β-strand	135-137	3	3
α-helix	138-146	9

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Small conductance calcium-activated potassium channel protein 2	B	protein	102	Rattus norvegicus	P70604 (AlphaFold model)
Calmodulin	R	protein	149	Rattus norvegicus	P0DP29 (AlphaFold model)

Sequence of entity 1 (B), FASTA

>4G28_1 Small conductance calcium-activated potassium channel protein 2 (chains B)
MGRKLELTKAEKHVHNFMMDTQLTKRVKNAAANVLRETWLIYKNTKLVKKIDHAKVRKHQ
RKFLQAIHQLRSVKMEQRKLNDQANTLVDLAKTQLEHHHHHH

Sequence of entity 2 (R), FASTA

>4G28_2 Calmodulin (chains R)
MADQLTEEQIAEFKEAFSLFDKDGDGTITTKELGTVMRSLGQNPTEAELQDMINEVDADG
NGTIDFPEFLTMMARKMKDTDSEEEIREAFRVFDKDGNGYISAAELRHVMTNLGEKLTDE
EVDEMIREADIDGDGQVNYEEFVQMMTAK

Ligands and cofactors

ID	Name	Formula	Copies
0W8	1-ethyl-1,3-dihydro-2H-benzimidazol-2-one	C9 H10 N2 O	1
CA	Calcium ion	Ca	2

Water and common crystallization additives (GOL, SO4) are not listed.

Primary citation

Identification of the functional binding pocket for compounds targeting small-conductance Ca(2+)-activated potassium channels. Zhang, M., Pascal, J.M., Schumann, M. et al. Nat Commun (2012) 3:1021-1021. DOI 10.1038/ncomms2017 · 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…
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…
8V2H 3.1 Å, Cryo-EM structure of the KCa2.2 channel bound to inhibitor AP14145.

Browse structure collections

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