3SJQ: Calmodulin

Crystal structure of a small conductance potassium channel splice variant complexed with calcium-calmodulin. Determined by X-ray diffraction at 1.9 Å resolution. Released 30 May 2012.

Method: X-ray diffraction
Resolution: 1.9 Å
Organism: Rattus norvegicus
Chains: 4
Atoms: 4,171
Mol. weight: 56.78 kDa
Ligands: CA, PHU
Released: 30 May 2012

Explore 3SJQ in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

3SJQ contains 18 α-helices and 8 β-strands across 4 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: 7 helices, 4 β-strands

Element	Residues	Length	Sheet
α-helix	6-19	14
β-strand	26-27	2	1
α-helix	29-38	10
α-helix	45-53	9
β-strand	63-64	2	1
α-helix	65-92	28
β-strand	99-100	2	2
α-helix	102-112	11
α-helix	118-128	11
β-strand	136-137	2	2
α-helix	138-146	9

Chain B: 7 helices, 4 β-strands

Element	Residues	Length	Sheet
α-helix	6-19	14
β-strand	27	1	3
α-helix	29-38	10
α-helix	45-53	9
β-strand	63	1	3
α-helix	65-92	28
β-strand	99-100	2	4
α-helix	102-111	10
α-helix	118-128	11
β-strand	136-137	2	4
α-helix	138-145	8

Chain C: 2 helices, 0 β-strands

Element	Residues	Length	Sheet
α-helix	415-439	25
α-helix	446-488	43

Chain D: 2 helices, 0 β-strands

Element	Residues	Length	Sheet
α-helix	416-439	24
α-helix	446-488	43

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Calmodulin	A, B	protein	149	Rattus norvegicus	P0DP29 (AlphaFold model)
Small conductance calcium-activated potassium channel protein 2	C, D	protein	87	Rattus norvegicus	P70604 (AlphaFold model)

Sequence of entity 1 (A, B), FASTA

>3SJQ_1 Calmodulin (chains A, B)
MADQLTEEQIAEFKEAFSLFDKDGDGTITTKELGTVMRSLGQNPTEAELQDMINEVDADG
NGTIDFPEFLTMMARKMKDTDSEEEIREAFRVFDKDGNGYISAAELRHVMTNLGEKLTDE
EVDEMIREADIDGDGQVNYEEFVQMMTAK

Sequence of entity 2 (C, D), FASTA

>3SJQ_2 Small conductance calcium-activated potassium channel protein 2 (chains C, D)
MDTQLTKRVKNAAANVLRETWLIYKNTKLVKKIDHAKVRKHQRKFLQAIHQARKLRSVKM
EQRKLNDQANTLVDLAKTQLEHHHHHH

Ligands and cofactors

ID	Name	Formula	Copies
CA	Calcium ion	Ca	8
PHU	1-phenylurea	C7 H8 N2 O	4

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

Primary citation

Structural basis for calmodulin as a dynamic calcium sensor. Zhang, M., Abrams, C., Wang, L. et al. Structure (2012) 20:911-923. DOI 10.1016/j.str.2012.03.019 · PubMed

Other PDB entries of the same protein (UniProt P0DP29 (AlphaFold model), which also has an AlphaFold model), best resolution first:

2PQ3 1.3 Å, N-Terminal Calmodulin Zn-Trapped Intermediate
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…
3B32 1.6 Å, Crystal Structure of Calcium-Saturated Calmodulin N-Terminal Domain Fragment, Residues…
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…
9M6G 1.7 Å, the crystal structure of the Ca2+/CaM-CASK-CaMK-Mint1-CID complex
9KYS 1.76 Å, the Ca2+/CaM-CASK-ARD complex
6MBA 1.8 Å, Crystal Structure of Human Nav1.4 CTerminal Domain in Complex with apo Calmodulin
9M5Y 1.8 Å, the crystal structure of the Ca2+/CaM-CASK-CaMK complex
9U9D 1.8 Å, Bipartite Genetically Encoded Biosensor sG-GECO1

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