Easy passage for fluoride ions revealed in new structure

Professor Mark Sansom, Head of Department

News Highlight

Easy passage for fluoride ions revealed in new structure

Fluc channel from Bordetella pertussis (Bpe). Homodimer viewed parallel to the membrane, with colouring according to the transmembrane helix schematic on left (Click to enlarge)

A collaboration between Simon Newstead and researchers in the States has led to the discovery of the structure of an ion channel that rids cells of toxic fluoride ions.

Simon Newstead, working with Christopher Miller and Randy Stockbridge at Brandeis University and Shohei Koide at the University of Chicago, have published the work on the dual-topology ion channel Fluc in Nature (1).

The Fluc family of ion channels is found in organisms from bacteria to eukaryotes. They export fluoride ions, which are toxic because they inhibit certain phosphoryl-transfer enzymes, out of the cell. Microorganisms in particular are continuously exposed to fluoride ions, which are present in soil and water.

Recent work from Professor Miller's lab on the Fluc channels showed that they have unusual properties (2, 3). They have a dual-topology architecture - two identical subunits are arranged in an inverted dimer orientiation to form the active channel, an assembly not previously seen in ion channels but common in multidrug transporters. The channels also show extreme selectivity towards fluoride ions over the more abundant chloride ions.

Whilst Professor Miller was in Oxford as a Newton Abraham Visiting Professor in 2013-14, his and Professor Newstead's paths crossed. This led to collaboration on the X-ray structure of the Fluc channel.

Beyond my understanding but some of you may be interested.