Calmodulin binding domain

CaMBD
solution structure of the calmodulin binding domain (cambd) of small conductanceCa^2+-activated potassium channels (sk2)
Identifiers
Symbol	CaMBD
Pfam	PF02888
InterPro	IPR004178
SCOP	1kkd
SUPERFAMILY	1kkd
Available protein structures: Pfam structures PDB RCSB PDB; PDBe; PDBj PDBsum structure summary

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.

References

1. Schumacher MA, Rivard AF, Bachinger HP, Adelman JP (April 2001). "Structure of the gating domain of a Ca²⁺-activated K+ channel complexed with Ca²⁺/calmodulin". Nature 410 (6832): 1120–4. doi:10.1038/35074145. PMID 11323678.

This article incorporates text from the public domain Pfam and InterPro IPR004178