摘要：

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(1). Previously, we expressed and purified a prokaryotic ClC channel homologue(2). 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 Angstrom resolution, which shows off-axis water-filled pores within the dimeric channel complex.

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