GenePage for the flc gene of Escherichia coli K-12

Primary Gene Name: flc
EcoGene Accession Number: EG12209
K-12 Gene Accession Number: ECK0617
MG1655 Gene Identifier: b0624
Gene Name Mnemonic: Fluoride channel
Alternate Gene Symbols: crcB; fluC; ybeI
Description: Fluoride efflux channel, dual topology membrane protein; Fluc protein
  # bp Upstream # bp Downstream
MW: 13777.31 ---------127 aa Pre-Run BlastP UniProt
Pre-Run BlastP NR+Env
Left End: 657555
Left Intergenic Region

Name: cspE_flc

Length: 53 bp gap

Orientation: Convergent

Left_end: 657502

Right_end: 657554

Centisome: 14.17

Genomic Address
Counterclockwise
Minute or Centisome (%) = 14.17
Right End: 657938
Right Intergenic Region

Name: flc_ybeM

Length: 92 bp gap

Orientation: Divergent

Left_end: 657939

Right_end: 658030

Centisome: 14.17

An E. coli K-12 flc(crcB) deletion confers hypersensitivity to NaF, consistent with Flc(CrcB) being a fluoride ion efflux channel; the camphor sensitivity phenotype of an flc(crcB) mutant may be due to contaminating NaF in camphor (Baker, 2012; Stockbridge, 2012). The E. coli K-12 Flc(CrcB) protein is a dual-topopogy membrane protein (Rapp, 2006). A Flc(CrcB) family protein from an E. coli virulence plasmid has been shown to be a homodimeric inner membrane fluoride-specific efflux channel; the membrane topologies of Flc(CrcB) family members from B. pertussis and L. acidophilus have four transmembrane helices and the Flc(CrcB) subunits have opposite orientation topologies; the CrcB family of fluoride export channels has been renamed as the Fluc family (Stockbridge, 2013). There is already a flu gene in E. coli so crcB has been renamed as flc instead of fluC, which is retained as a synonym. E. coli K-12 Flc(CrcB) is an inner membrabe proteono with four predicted transmembrane helicies (Daley, 2005). A cspE-pagP-flc(crcB) clone compensates for a loss of the normal condensin MukBEF and recondenses chromosomes decondensed by camphor treatment (Hu, 1996; Sand, 2003). A cspE-pagP-flc(crcB) clone increases plasmid DNA supercoiling and reduces DNA gyrase and topoisomerase IV mutant phenotypes (Sand, 2003). A cspE-flc(crcB) double mutant confers camphor-hypersensitivity and exacerbates the phenotypes of topo IV and MukB mutants, indicating that CspE and Flc(CrcB) may have roles in maintaining condensed chromosomes, either direct or indirect, possibly through the regulation of other gene products (Sand, 2003). Multicopy expression of cspE alone confers 10-fold camphor-resistance, a cspE-flc(crcB) clone confers 100-fold resistance, and the cspE-pagP-flc(crcB) clone confers 1000-fold resistance (single flc(crcB) or pagP clones had no effect); it is not known if the pagP gene product is contributing or if the three gene clone just expresses more flc(crcB) and/or cspE (Sand, 2003).

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BamHI EcoRI HindIII