Calmodulin binding domain

In molecular biology, calmodulin binding domain (CaMBD) is a protein domain found in small-conductance calcium-activated potassium channels (SK channels). These channels are independent of voltage and gated solely by intracellular Ca²⁺. They are heteromeric complexes that comprise pore-forming alpha-subunits and the Ca²⁺-binding protein calmodulin (CaM).^[1] CaM binds to the SK channel through the CaMBD, which is located in an intracellular region of the alpha-subunit immediately carboxy-terminal to the pore. Channel opening is triggered when Ca²⁺ binds the EF hands in the N-lobe of CaM. The structure of this domain complexed with CaM is known.^[1] This domain forms an elongated dimer with a CaM molecule bound at each end; each CaM wraps around three alpha-helices, two from one CaMBD subunit and one from the other.

CaMBD
solution structure of the calmodulin binding domain (cambd) of small conductanceCa2+-activated potassium channels (sk2)
Identifiers
Symbol	CaMBD
Pfam	PF02888
InterPro	IPR004178
SCOP2	1kkd / SCOPe / SUPFAM
Available protein structures: Pfam   structures / ECOD   PDB RCSB PDB; PDBe; PDBj PDBsum structure summary