TCDB is operated by the Saier Lab Bioinformatics Group
TCIDNameDomainKingdom/PhylumProtein(s)
*1.A.43.1.1









The camphor resistance protein, CrcB or FluC (Hu et al. 1996; Sand et al. 2003).  Exports fluoride selectively over chloride by an anion open channel mechanism (Stockbridge et al. 2013).  The active transporter is a dimer of 4 TMS subunits arranged in an antiparallel transmembrane orientation (Stockbridge et al. 2014).  In bacteria lacking Fluc, F- accumulates when the external medium is acidified as a predicted function of the transmembrane pH gradient. This weak acid accumulation effect, which results from the high pKa (3.4) and membrane permeability of HF, is abolished by Fluc channels (Sand et al. 2003).  Exports fluoride selectively over chloride by an anion open channel mechanism (Stockbridge et al. 2013).  The active transporter is a dimer of 4 TMS subunits arranged in an antiparallel transmembrane orientation (Stockbridge et al. 2014).  In bacteria lacking Fluc, F- accumulates when the external medium is acidified as a predicted function of the transmembrane pH gradient. This weak acid accumulation effect, which results from the high pKa (3.4) and membrane permeability of HF, is abolished by Fluc channels (Ji et al. 2014).

Bacteria
Proteobacteria
CrcB of E. coli (P37002)
*1.A.43.1.2









Protein CrcB homologue 2

Bacteria
Firmicutes
crcB2 of Bacillus subtilis
*1.A.43.1.3









Putative fluoride-selective channel of 143 aas and 4 TMSs, CrcB.

Bacteria
Actinobacteria
CreB of Propionibacterium acnes
*1.A.43.1.4









CreB homologue of 124 aas

Archaea
Euryarchaeota
CrcB homologue of Methanocaldococcus fervens
*1.A.43.1.5









CrcB homologue of 172 aas and 4 TMSs

Bacteria
Proteobacteria
CrcB of Parvularcula bermudensis
*1.A.43.1.6









Putative fluoride exporter, CrcB.

Bacteria
Bacteroidetes/Chlorobi group
CrcB of Pelodictyon luteolum (Chlorobium luteolum)
*1.A.43.1.7









Putative fluoride exporter, CrcB if 114 aas and 4 TMSs.

Archaea
Euryarchaeota
CrcB of Thermococcus barophilus
*1.A.43.1.8









Uncharacterized protein of 151 aas and 4 TMSs.

Bacteria
Actinobacteria
UP of Rothia mucilaginosa (Stomatococcus mucilaginosus)
*1.A.43.1.9









Putative fluoride exporter, CrcB of 113 aas and 4 TMSs.

Archaea
Euryarchaeota
UP of Haloquadratum walsbyi
*1.A.43.1.10









CrcB-like protein of 164 aas and 4 TMSs

Bacteria
Actinobacteria
CreB of Mobiluncus curtisii (Falcivibrio vaginalis)
*1.A.43.1.11









Putative fluoride transporter of 122 aas, CrcB

Bacteria
Proteobacteria
CrcB of Campylobacter jejuni
*1.A.43.1.12









CreB of 168 aas and 4 TMSs

Bacteria
Actinobacteria
CreB of Brachybacterium faecium
*1.A.43.1.13









CreB of 123 aas and 4 TMSs.

Bacteria
Bacteroidetes/Chlorobi group
CreB of Aequorivita sublithincola
*1.A.43.1.14









CrcB, putative fluoride channel protein of 124 aas and 4 TMSs

Bacteria
Firmicutes
CrcB of Lactobacillus kefiranofaciens
*1.A.43.1.15









CrcB of 133 aas and 4 TMSs.

Archaea
Euryarchaeota
CrcB of Halorubrum coriense
*1.A.43.1.16









Fluc homologue of 453 aas and 9 putative TMSs.

Eukaryota
Longamoebia
Fluc of Acanthamoeba castellanii
*1.A.43.1.17









Fluoride ion channel of 128 aas and 4 TMSs, Fluc or CrcB.  The crystal structure is known (PDB5A40; 5A43).

Bacteria
Proteobacteria
Fluc of Bordetella pertussis
*1.A.43.2.1









CrcB-like protein of 307 aas and 6 TMSs in an apparent 3 + 3 arrangement.

Eukaryota
Intramacronucleata
CrcB homologue of Tetrahymena thermophila
*1.A.43.2.2









Uncharacterized protein of 372 aas and 9 - 10 TMSs

Eukaryota
Fungi
UP of Kazachstania africana (Kluyveromyces africanus)
*1.A.43.2.3









CrcB domain containing protein of 310 aas and 9 TMSs in a 4 + 5 arrangement, with both halves showing sequence similarity with the 4 TMS CrcB of E. coli.

Eukaryota
Fungi
CrcB homologue of Schizosaccharomyces cryophilus
*1.A.43.2.4









Plasma membrane fluoride ( > chloride) export channel of 375 aas and 8 TMSs, FEX1 (Li et al. 2013). The two homologous 4 TMS domains are functionally assymetric (Smith et al. 2015).  There are two very similar fex genes in S. cerevisiae, the other having TC# 1.A.43.2.5. Fex1 is consitutively synthesized (Smith et al. 2015).

Eukaryota
Fungi
FEX1 of Saccharomyces cerevisiae
*1.A.43.2.5









Fluoride exporter, FEX2 of 375 aas and 8 TMSs (Li et al. 2013).

Eukaryota
Fungi
FEX2 of Saccharomyces cerevisiae
*1.A.43.2.6









Fluoride exporter, FEX, of 526 aas and 10 putative TMSs (Li et al. 2013).

Eukaryota
Fungi
FEX of Neurospora crassa
*1.A.43.2.7









Camphor resistance CrcB protein of 461 aas and 9 putative TMSs.

Eukaryota
Viridiplantae
CrcB of Arabidopsis thaliana
*1.A.43.2.8









Uncharacterized protein of 405 aas and 8 putative TMSs.

Eukaryota
Metazoa
UP of Ciona intestinalis (Transparent sea squirt) (Ascidia intestinalis)
*1.A.43.2.9









Uncharacterized protein of 460 aas and 9 TMSs/

Eukaryota
Oomycetes
UP of Phytophthora parasitica
*1.A.43.3.1









CreB of 346 aas and 4 TMSs.

Bacteria
Actinobacteria
CreB of Bifidobacterium longum
*1.A.43.3.2









Putative fluoride channel, CrcB, of 180 aas and 4 TMSs.

Bacteria
Actinobacteria
CrcB of Scardovia wiggsiae
*1.A.43.3.3









Putative fluoride ion channnel, CrcB, of 178 aas and 4 TMSs

Bacteria
Actinobacteria
CrcB of Bifidobacterium longum
*1.A.43.3.4









Putative fluoride ion channel, CrcB, with 310 aas and 4 TMSs.

Bacteria
Actinobacteria
CrcB of Bifidobacterium animalis subsp. lactis