Crystal Structure of a Kir3.1-Prokaryotic Kir Channel Chimera

Journal Article · Mon Jan 01 00:00:00 EST 2007 · EMBO Journal

DOI:https://doi.org/10.1038/sj.emboj.7601828· OSTI ID:959664

Nishida, M; Cadene, M; Chait, B; MacKinnon, R

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 Angstroms. The selectivity filter is identical to the Streptomyces lividans K+ channel within error of measurement (r.m.s.d.<0.2 Angstroms), suggesting that K+ selectivity requires extreme conservation of three-dimensional structure. Multiple K+ ions reside within the pore and help to explain voltage-dependent Mg2+ 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.

• Research Organization: Brookhaven National Laboratory (BNL) National Synchrotron Light Source
• Sponsoring Organization: Doe - Office Of Science
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 959664
• Report Number(s): BNL--82650-2009-JA
• Journal Information: EMBO Journal, Journal Name: EMBO Journal Vol. 26; ISSN EMJODG; ISSN 0261-4189
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CHIMERAS
CRYSTAL STRUCTURE
ESCHERICHIA COLI
GTP-ASES
LIPIDS
MEMBRANES
ORIGIN
RESIDUES
STREPTOMYCES
national synchrotron light source