2QKS

Crystal structure of a Kir3.1-prokaryotic Kir channel chimera

Summary for 2QKS

• Entry DOI: 10.2210/pdb2qks/pdb
• Descriptor: Kir3.1-prokaryotic Kir channel chimera, nonyl beta-D-glucopyranoside, POTASSIUM ION, ... (4 entities in total)
• Functional Keywords: chimera, g-protein gated inward rectifier, potassium channel, selectivity filter, metal transport
• Biological source: Mus musculus (Mouse); More
• Total number of polymer chains: 2
• Total formula weight: 73128.74

Authors

Nishida, M.,MacKinnon, R. (deposition date: 2007-07-11, release date: 2007-08-28, Last modification date: 2023-08-30)

Primary citation

Nishida, M.,Cadene, M.,Chait, B.T.,Mackinnon, R.
Crystal structure of a Kir3.1-prokaryotic Kir channel chimera.
Embo J., 26:4005-4015, 2007

PubMed Abstract: The Kir3.1 K(+) channel participates in heart rate control and neuronal excitability through G-protein and lipid signaling pathways. Expression in Escherichia coli has been achieved by replacing three fourths of the transmembrane pore with the pore of a prokaryotic Kir channel, leaving the cytoplasmic pore and membrane interfacial regions of Kir3.1 origin. Two structures were determined at 2.2 A. The selectivity filter is identical to the Streptomyces lividans K(+) channel within error of measurement (r.m.s.d.<0.2 A), suggesting that K(+) selectivity requires extreme conservation of three-dimensional structure. Multiple K(+) ions reside within the pore and help to explain voltage-dependent Mg(2+) and polyamine blockade and strong rectification. Two constrictions, at the inner helix bundle and at the apex of the cytoplasmic pore, may function as gates: in one structure the apex is open and in the other, it is closed. Gating of the apex is mediated by rigid-body movements of the cytoplasmic pore subunits. Phosphatidylinositol 4,5-biphosphate-interacting residues suggest a possible mechanism by which the signaling lipid regulates the cytoplasmic pore.

PubMed: 17703190
DOI: 10.1038/sj.emboj.7601828

Experimental method

X-RAY DIFFRACTION (2.2 Å)