2EXW

Crystal structure of a EcClC-Fab complex in the absence of bound ions

Summary for 2EXW

• Entry DOI: 10.2210/pdb2exw/pdb
• Related: 1OTS 2exy 2ez0
• Descriptor: H(+)/Cl(-) exchange transporter clcA, Fab Fragment (Heavy Chain), Fab Fragment (Light Chain) (3 entities in total)
• Functional Keywords: clc family of cl- channels and transporters, h+/cl- antiporter, membrane protein-fab complex, membrane protein
• Biological source: Escherichia coli; More
• Cellular location: Cell inner membrane; Multi-pass membrane protein (Probable): P37019
• Total number of polymer chains: 6
• Total formula weight: 194603.75

Authors

Lobet, S.,Dutzler, R. (deposition date: 2005-11-09, release date: 2006-01-24, Last modification date: 2024-11-13)

Primary citation

Lobet, S.,Dutzler, R.
Ion-binding properties of the ClC chloride selectivity filter.
Embo J., 25:24-33, 2006

PubMed Abstract: 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.

PubMed: 16341087
DOI: 10.1038/sj.emboj.7600909

Experimental method

X-RAY DIFFRACTION (3.2 Å)