1g4y
From Proteopedia
1.60 A CRYSTAL STRUCTURE OF THE GATING DOMAIN FROM SMALL CONDUCTANCE POTASSIUM CHANNEL COMPLEXED WITH CALCIUM-CALMODULIN
Overview
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.
About this Structure
1G4Y is a Protein complex structure of sequences from Rattus norvegicus. Full crystallographic information is available from OCA.
Reference
Structure of the gating domain of a Ca2+-activated K+ channel complexed with Ca2+/calmodulin., Schumacher MA, Rivard AF, Bachinger HP, Adelman JP, Nature. 2001 Apr 26;410(6832):1120-4. PMID:11323678 Page seeded by OCA on Fri May 2 17:08:37 2008
