1G4Y: 1.60 A Crystal Structure Of The Gating Domain From Small Conductance Potassium Channel Complexed With Calcium-Calmodulin

Citation:
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.
PDB ID: 1G4YDownload
MMDB ID: 16082
PDB Deposition Date: 2001/1/7
Updated in MMDB: 2011/11
Experimental Method:
x-ray diffraction
Resolution: 1.6  Å
Source Organism:
Similar Structures:
Biological Unit for 1G4Y: tetrameric; determined by author and by software (PISA,PQS)
Molecular Components in 1G4Y
Label Count Molecule
Proteins (4 molecules)
2
Calcium-activated Potassium Channel Rsk2(Gene symbol: Kcnn2)
Molecule annotation
2
Calmodulin
Molecule annotation
Chemicals (6 molecules)
1
2
2
4
* Click molecule labels to explore molecular sequence information.

Citing MMDB
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