3BXK: Calmodulin

Crystal structure of the P/Q-type calcium channel (CaV2.1) IQ domain and CA2+calmodulin complex. Determined by X-ray diffraction at 2.55 Å resolution. Released 25 Mar 2008.

Method: X-ray diffraction
Resolution: 2.55 Å
Organism: Rattus norvegicus
Chains: 4
Atoms: 2,601
Mol. weight: 39.25 kDa
Ligands: CA
Released: 25 Mar 2008

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

Secondary structure: helices and β-sheets

3BXK contains 19 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: 8 helices, 4 β-strands

Element	Residues	Length	Sheet
α-helix	6-19	14
β-strand	27	1	1
α-helix	29-38	10
α-helix	47-55	9
β-strand	63	1	1
α-helix	65-74	10
α-helix	82-92	11
β-strand	100-101	2	2
α-helix	102-111	10
α-helix	118-128	11
β-strand	135-136	2	2
α-helix	138-143	6

Chain B: 1 helix, 0 β-strands

Element	Residues	Length	Sheet
α-helix	1961-1975	15

Chain C: 9 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	45-55	11
β-strand	63	1	3
α-helix	65-75	11
α-helix	79-81	3
α-helix	82-92	11
β-strand	99-100	2	4
α-helix	102-111	10
α-helix	118-128	11
β-strand	136-137	2	4
α-helix	138-144	7

Chain D: 1 helix, 0 β-strands

Element	Residues	Length	Sheet
α-helix	1961-1977	17

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Calmodulin	A, C	protein	148	Rattus norvegicus	P0DP29 (AlphaFold model)
Voltage-dependent P/Q-type calcium channel subunit alpha-1A peptide	B, D	protein	21		O00555 (AlphaFold model)

Sequence of entity 1 (A, C), FASTA

>3BXK_1 Calmodulin (chains A, C)
ADQLTEEQIAEFKEAFSLFDKDGDGTITTKELGTVMRSLGQNPTEAELQDMINEVDADGN
GTIDFPEFLTMMARKMKDTDSEEEIREAFRVFDKDGNGYISAAELRHVMTNLGEKLTDEE
VDEMIREADIDGDGQVNYEEFVQMMTAK

Sequence of entity 2 (B, D), FASTA

>3BXK_2 Voltage-dependent P/Q-type calcium channel subunit alpha-1A peptide (chains B, D)
KIYAAMMIMEYYRQSKAKKLQ

Ligands and cofactors

ID	Name	Formula	Copies
CA	Calcium ion	Ca	8

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

Primary citation

Crystal structure of the P/Q-type calcium channel (CaV2.1) IQ domain and CA2+calmodulin complex. Mori, M.X., Vander Kooi, C.W., Leahy, D.J. et al. To be published.

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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