7KK9

Fluoride channel Fluc-Ec2 mutant S81A/T82A with bromide

Summary for 7KK9

• Entry DOI: 10.2210/pdb7kk9/pdb
• Descriptor: Putative fluoride ion transporter CrcB, monobody, BROMIDE ION, ... (5 entities in total)
• Functional Keywords: fluoride channel, membrane protein
• Biological source: Escherichia coli; More
• Total number of polymer chains: 4
• Total formula weight: 49520.10

Authors

McIlwain, B.C.,Stockbridge, R.B. (deposition date: 2020-10-27, release date: 2021-08-04, Last modification date: 2023-10-18)

Primary citation

McIlwain, B.C.,Gundepudi, R.,Koff, B.B.,Stockbridge, R.B.
The fluoride permeation pathway and anion recognition in Fluc family fluoride channels.
Elife, 10:-, 2021

PubMed Abstract: Fluc family fluoride channels protect microbes against ambient environmental fluoride by undermining the cytoplasmic accumulation of this toxic halide. These proteins are structurally idiosyncratic, and thus the permeation pathway and mechanism have no analogy in other known ion channels. Although fluoride-binding sites were identified in previous structural studies, it was not evident how these ions access aqueous solution, and the molecular determinants of anion recognition and selectivity have not been elucidated. Using x-ray crystallography, planar bilayer electrophysiology, and liposome-based assays, we identified additional binding sites along the permeation pathway. We used this information to develop an oriented system for planar lipid bilayer electrophysiology and observed anion block at one of these sites, revealing insights into the mechanism of anion recognition. We propose a permeation mechanism involving alternating occupancy of anion-binding sites that are fully assembled only as the substrate approaches.

PubMed: 34250906
DOI: 10.7554/eLife.69482

Experimental method

X-RAY DIFFRACTION (3.1 Å)