Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2001 Apr 26;410(6832):1120-4.
doi: 10.1038/35074145.

Structure of the Gating Domain of a Ca2+-activated K+ Channel Complexed With Ca2+/calmodulin

Affiliations

Structure of the Gating Domain of a Ca2+-activated K+ Channel Complexed With Ca2+/calmodulin

M A Schumacher et al. Nature. .

Abstract

Small-conductance Ca2+-activated K+ channels (SK channels) are independent of voltage and gated solely by intracellular Ca2+. These membrane channels are heteromeric complexes that comprise pore-forming alpha-subunits and the Ca2+-binding protein calmodulin (CaM). CaM binds to the SK channel through the CaM-binding domain (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. Here we report the 1.60 A crystal structure of the SK channel CaMBD/Ca2+/CaM complex. The CaMBD 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. As only the CaM N-lobe has bound Ca2+, the structure provides a view of both calcium-dependent and -independent CaM/protein interactions. Together with biochemical data, the structure suggests a possible gating mechanism for the SK channel.

Similar articles

See all similar articles

Cited by 210 articles

See all "Cited by" articles

Publication types

Substances

LinkOut - more resources

Feedback