Structural highlights
Function
CRCB_BORPE Important for reducing fluoride concentration in the cell, thus reducing its toxicity.
Publication Abstract from PubMed
To contend with hazards posed by environmental fluoride, microorganisms export this anion through F(-)-specific ion channels of the Fluc family. Since the recent discovery of Fluc channels, numerous idiosyncratic features of these proteins have been unearthed, including strong selectivity for F(-) over Cl(-) and dual-topology dimeric assembly. To understand the chemical basis for F(-) permeation and how the antiparallel subunits convene to form a F(-)-selective pore, here we solve the crystal structures of two bacterial Fluc homologues in complex with three different monobody inhibitors, with and without F(-) present, to a maximum resolution of 2.1 A. The structures reveal a surprising 'double-barrelled' channel architecture in which two F(-) ion pathways span the membrane, and the dual-topology arrangement includes a centrally coordinated cation, most likely Na(+). F(-) selectivity is proposed to arise from the very narrow pores and an unusual anion coordination that exploits the quadrupolar edges of conserved phenylalanine rings.
Crystal structures of a double-barrelled fluoride ion channel.,Stockbridge RB, Kolmakova-Partensky L, Shane T, Koide A, Koide S, Miller C, Newstead S Nature. 2015 Sep 24;525(7570):548-51. doi: 10.1038/nature14981. Epub 2015 Sep 7. PMID:26344196[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Stockbridge RB, Kolmakova-Partensky L, Shane T, Koide A, Koide S, Miller C, Newstead S. Crystal structures of a double-barrelled fluoride ion channel. Nature. 2015 Sep 24;525(7570):548-51. doi: 10.1038/nature14981. Epub 2015 Sep 7. PMID:26344196 doi:http://dx.doi.org/10.1038/nature14981