2exw
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Crystal structure of a EcClC-Fab complex in the absence of bound ions
OverviewOverview
The ClC channels are members of a large protein family of chloride (Cl-) channels and secondary active Cl- transporters. Despite their diverse functions, the transmembrane architecture within the family is conserved. Here we present a crystallographic study on the ion-binding properties of the ClC selectivity filter in the close homolog from Escherichia coli (EcClC). The ClC selectivity filter contains three ion-binding sites that bridge the extra- and intracellular solutions. The sites bind Cl- ions with mM affinity. Despite their close proximity within the filter, the three sites can be occupied simultaneously. The ion-binding properties are found conserved from the bacterial transporter EcClC to the human Cl- channel ClC-1, suggesting a close functional link between ion permeation in the channels and active transport in the transporters. In resemblance to K+ channels, ions permeate the ClC channel in a single file, with mutual repulsion between the ions fostering rapid conduction.
About this StructureAbout this Structure
2EXW is a Single protein structure of sequence from Escherichia coli and Mus musculus. Full crystallographic information is available from OCA.
ReferenceReference
Ion-binding properties of the ClC chloride selectivity filter., Lobet S, Dutzler R, EMBO J. 2006 Jan 11;25(1):24-33. Epub 2005 Dec 8. PMID:16341087
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