5NKQ

Crystal structure of a dual topology fluoride ion channel.

Replaces:  5FXBReplaces:  5A41

Summary for 5NKQ

• Entry DOI: 10.2210/pdb5nkq/pdb
• Descriptor: Putative fluoride ion transporter CrcB, Monobody, SODIUM ION, ... (5 entities in total)
• Functional Keywords: dual topology channel, fluoride channel, monobody, transport protein
• Biological source: Bordetella pertussis; More
• Cellular location: Cell inner membrane ; Multi-pass membrane protein : Q7VYU0
• Total number of polymer chains: 8
• Total formula weight: 93816.90

Authors

Stockbridge, R.,Miller, C.,Newstead, S. (deposition date: 2017-03-31, release date: 2017-04-26, Last modification date: 2024-01-17)

Primary citation

Stockbridge, R.B.,Kolmakova-Partensky, L.,Shane, T.,Koide, A.,Koide, S.,Miller, C.,Newstead, S.
Crystal structures of a double-barrelled fluoride ion channel.
Nature, 525:548-551, 2015

PubMed Abstract: 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 Å. 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.

PubMed: 26344196
DOI: 10.1038/nature14981

Experimental method

X-RAY DIFFRACTION (2.17 Å)