1kpl
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Crystal Structure of the ClC Chloride Channel from S. typhimurium
OverviewOverview
The ClC chloride channels catalyse the selective flow of Cl- ions across cell membranes, thereby regulating electrical excitation in skeletal muscle and the flow of salt and water across epithelial barriers. Genetic defects in ClC Cl- channels underlie several familial muscle and kidney diseases. Here we present the X-ray structures of two prokaryotic ClC Cl- channels from Salmonella enterica serovar typhimurium and Escherichia coli at 3.0 and 3.5 A, respectively. Both structures reveal two identical pores, each pore being formed by a separate subunit contained within a homodimeric membrane protein. Individual subunits are composed of two roughly repeated halves that span the membrane with opposite orientations. This antiparallel architecture defines a selectivity filter in which a Cl- ion is stabilized by electrostatic interactions with alpha-helix dipoles and by chemical coordination with nitrogen atoms and hydroxyl groups. These findings provide a structural basis for further understanding the function of ClC Cl- channels, and establish the physical and chemical basis of their anion selectivity.
About this StructureAbout this Structure
1KPL is a Single protein structure of sequence from Salmonella typhimurium with , , and as ligands. Full crystallographic information is available from OCA.
ReferenceReference
X-ray structure of a ClC chloride channel at 3.0 A reveals the molecular basis of anion selectivity., Dutzler R, Campbell EB, Cadene M, Chait BT, MacKinnon R, Nature. 2002 Jan 17;415(6869):287-94. PMID:11796999
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