4QNH: Calcium-calmodulin

Calcium-calmodulin (T79D) complexed with the calmodulin binding domain from a small conductance potassium channel SK2-a. Determined by X-ray diffraction at 2.02 Å resolution. Released 6 Aug 2014.

Method: X-ray diffraction
Resolution: 2.02 Å
Organism: Rattus norvegicus
Chains: 2
Atoms: 2,083
Mol. weight: 29.29 kDa
Ligands: CA
Released: 6 Aug 2014

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

Secondary structure: helices and β-sheets

4QNH 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	45-54	10
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	102-111	10
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

>4QNH_1 Small conductance calcium-activated potassium channel protein 2 (chains B)
MGRKLELTKAEKHVHNFMMDTQLTKRVKNAAANVLRETWLIYKNTKLVKKIDHAKVRKHQ
RKFLQAIHQLRSVKMEQRKLNDQANTLVDLAKTQLEHHHHHH

Sequence of entity 2 (R), FASTA

>4QNH_2 Calmodulin (chains R)
MADQLTEEQIAEFKEAFSLFDKDGDGTITTKELGTVMRSLGQNPTEAELQDMINEVDADG
NGTIDFPEFLTMMARKMKDDDSEEEIREAFRVFDKDGNGYISAAELRHVMTNLGEKLTDE
EVDEMIREADIDGDGQVNYEEFVQMMTAK

Ligands and cofactors

ID	Name	Formula	Copies
CA	Calcium ion	Ca	2

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

Primary citation

Selective phosphorylation modulates the PIP2 sensitivity of the CaM-SK channel complex. Zhang, M., Meng, X.Y., Cui, M. et al. Nat Chem Biol (2014) 10:753-759. DOI 10.1038/nchembio.1592 · 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…
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

About this viewer

MolViewer shows 4QNH 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.