Projection structure of a ClC-type chloride channel at 6.5 A resolution.
Virtually all cells in all eukaryotic organisms express ion channels of the ClC type, the only known molecular family of chloride-ion-selective channels. The diversity of ClC channels highlights the multitude and range of functions served by gated chloride-ion conduction in biological membranes, such as controlling electrical excitability in skeletal muscle, maintaining systemic blood pressure, acidifying endosomal compartments, and regulating electrical responses of GABA (gamma-aminobutyric acid)-containing interneurons in the central nervous system. Previously, we expressed and purified a prokaryotic ClC channel homologue. Here we report the formation of two-dimensional crystals of this ClC channel protein reconstituted into phospholipid bilayer membranes. Cryo-electron microscopic analysis of these crystals yields a projection structure at 6.5 A resolution, which shows off-axis water-filled pores within the dimeric channel complex.
Mindell
J A
JA
Department of Biochemistry, Howard Hughes Medical Institute, Basic Medical Science Research Center, Brandeis University, Waltham, Massachusetts 02454, USA. jmindell@brandeis.edu
Maduke
M
M
Miller
C
C
Grigorieff
N
N
D018118:Chloride Channels / Q000737:chemistry*; D003001:Cloning, Molecular; D018360:Crystallography, X-Ray; D004926:Escherichia coli; D008051:Lipid Bilayers; D011487:Protein Conformation
D018118:Chloride Channels; D008051:Lipid Bilayers