TCDB is operated by the Saier Lab Bioinformatics Group
TCIDNameDomainKingdom/PhylumProtein(s)
*2.A.88.1.1









Biotin transporter, BioY (Biotin ECF transporter S component) (Hebbeln et al., 2007; Rodionov et al., 2009).

Bacteria
Proteobacteria
BioY of Rhizobium etli (Q6GUB0)
*2.A.88.1.2









The BioY homologue (190 aas; 6TMSs)
Bacteria
Proteobacteria
BioY homologue of Rickettsia typhi (Q68X47)
*2.A.88.1.3









Biotin transporter, BioY (Biotin ECF transporter S component) (Hebbeln et al. 2007; Rodionov et al., 2009). The functional unit is a dimer (Kirsch et al., 2012).

Bacteria
Proteobacteria
BioY of Rhodobacter capsulatus (D5ARG8)
*2.A.88.1.4









Biotin transporter, BioY of 201 aas and 6 TMSs.  Transports biotin with high affinity without other subunits (Finkenwirth et al. 2013).

Bacteria
Proteobacteria
BioY of Oceanicola batsensis
*2.A.88.1.5









Biotin transporter, BioY of 192 aas and 5 TMSs.  Transports biotin without other subunits (Finkenwirth et al. 2013).

Bacteria
Proteobacteria
BioY of Rhodopseudomonas palustris
*2.A.88.1.6









BioY of 195 aas and 6 TMSs.  Transports biotin with high affinity without additional subunits (Finkenwirth et al. 2013).

Bacteria
Proteobacteria
BioY of Ruegeria pomeroyi (Silicibacter pomeroyi)
*2.A.88.1.7









BioY biotin uptake porter.  (note: no AT energizer was found encoded in the genome of C. trachomatis (Fisher et al. 2012).

Bacteria
Chlamydiae/Verrucomicrobia group
BioY of Chlamydia trachomatis
*2.A.88.1.8









The distant BioY homologue (183 aas; 6 TMSs)
Bacteria
Proteobacteria
BioY homologue of Bordetella avium (Q2KUS5)
*2.A.88.1.9









Biotin transporter, BioY (Biotin ECF transporter S component) (Hebbeln et al., 2007; Rodionov et al., 2009).

Bacteria
Firmicutes
BioY of Bacillus subtilis (O07620)
*2.A.88.2.1









Folate transporter, FolT (Folate ECF transporter S component) (Rodionov et al., 2009). Regulated by a THF riboswitch (Ames et al. 2010).

 

Bacteria
Firmicutes
FolT of Clostridium acetobutylicum (Q97GE9)
*2.A.88.3.1









Thiamin transporter, ThiT (Thiamin ECF transporter S component) (Rodionov et al. 2002; Rodionov et al. 2009).

Bacteria
Firmicutes
YuaJ of Bacillus subtilis (O32074)
*2.A.88.3.2









Thiamin transporter, ThiT (Thiamin ECF transporter S component) (Rodionov et al. 2002; Rodionov et al., 2009). High affinity thiamin transporter ThiT (Ka=120 pM). Other substrates include TPP, TMP and pyrithiamin with nM binding constants at 1:1 stoichiometry (protein:ligand). Binding depends on a tryptophan-rich loop between TMSs 5 and 6 (Erkens and Slotboom, 2010). Erkens et al. (2011) presented the crystal structure of the thiamine-specific S-component of the ECF-type ABC transporter, ThiT from Lactococcus lactis at 2.0 Å. Extensive protein-substrate interactions explain its high binding affinity for thiamine (Kd ~ 10-10 M). ThiT has a fold similar to that of the riboflavin-specific S-component RibU, with which it shares only 14% sequence identity. Two alanines in a conserved motif (AxxxA) located on the membrane-embedded surface of the S-components mediate the interaction with the energizing module. A general transport mechanism for ECF transporters has been proposed (Erkens et al., 2011).  Substrate binding induces conformational changes in ThiT (Majsnerowska et al. 2013).

Bacteria
Firmicutes
ThiT of Lactococcus lactis (A2RI47)
*2.A.88.3.3









Thiamin transporter, ThiT (Thiamin ECF transporter S component) (Rodionov et al. 2002; Rodionov et al. 2009).

 

 

Bacteria
Firmicutes
ThiT of Lactobacillus casei (Q037U3)
*2.A.88.4.1









Tryptophan transporter TrpP (YhaG; Tryptophan ECF transporter S component) (Rodionov et al., 2009; Sarsero et al., 2000)

Bacteria
Firmicutes
TrpP of Bacillus subtilis (O07515)
*2.A.88.4.2









Putative dimethylbenzimidazole porter, CblT (dimethylbenzimidazole ECF transporter S component) Rodionov et al., 2009) Regulated by a Vitamin B12 riboswitch (Rodionov et al. 2003).

Bacteria
Firmicutes
CblT of Clostridium botulinum (A5I0E4)
*2.A.88.5.1









Putative niacin uptake transporter, NiaX (niacin ECF transporter S component) (Rodionov et al., 2009). 

Bacteria
Firmicutes
NiaX of Streptococcus pyogenes (Q99Z31)
*2.A.88.5.2









Putative niacin uptake transporter, NiaX (niacin ECF transporter S component) Rodionov et al., 2009).

Bacteria
Firmicutes
NiaX of Lactococcus lactis subsp. cremoris
*2.A.88.6.1









Putative queuosine precursor uptake transporter, QrtT  (queosine ECF transporter S component) (Rodionov et al., 2009) (5 or 6 TM5s).

Bacteria
Firmicutes
QrtT of Lactobacillus sakei (Q38XE8)
*2.A.88.7.1









Putative lipoate transporter, LipT (lipoate ECF transporter S component) (Rodionov et al., 2009).

Bacteria
Tenericutes
LipT of Onion yellows phytoplasma (Q6YQR5)
*2.A.88.8.1









Putative queuosine precursor transporter, YpdP (queuosine ECF transporter S component). Regulated by a preQ1 riboswitch (243 aas, 7 TMSs).

Bacteria
Firmicutes
YpdP of Staphylococcus lugdunensis (D3QD12)
*2.A.88.8.2









YhhQ transporter (Duf165)

Bacteria
Firmicutes
YhhQ transporter of Bacillus subtilis (P54163)
*2.A.88.8.3









YpdP transporter (Duf165) (229 aas; 7 TMSs)

Bacteria
Firmicutes
YpdP of Bacillus subtilis (G4P330)
*2.A.88.8.4









Duf165 transporter (229 aas; 5 TMSs)

Archaea
Euryarchaeota
Transporter of Methanosarcina mazei (Q8PW04)
*2.A.88.8.5









Putative ACR family transporter (DUF165) (261 aas; 6 TMSs)

Bacteria
Proteobacteria
ACR family transporter of Stenotrophomonas maltophilia (B2FPS5)
*2.A.88.8.6









YhhQ protein (DUF165) (encoded within the purine regulon (PurR) (Ravcheev et al., 2002)) (221 aas; 6 TMSs).  It may be a 7-cyano-7-deazaguanine (preQ₀) transporter. PreQ0 is the product of the reaction catalyzed by GTP cyclhydrolase I, important for the synthesis of folic acid, and an intermediate of interest due to its central role in tRNA and DNA modification and secondary metabolism (Zallot et al. 2017).

Bacteria
Proteobacteria
YhhQ of E. coli (B3WJF3)
*2.A.88.8.7









Uncharacterized protein; YpdP homologue of 248 aas and 6 TMSs.

Bacteria
Spirochaetes
UP of Treponema succinifaciens
*2.A.88.9.1









Predicted queuosine precursor transporter, QueT (queuosine ECF transporter S component) (Rodionov et al., 2009) (169 aas; 5 TMss).

Bacteria
Firmicutes
QueT of Lactococcus lactis (A2RM05) 
*2.A.88.9.2









Predicted queuosine precursor transporter, QueT (queuosine ECF transporter S component) (Rodionov et al., 2009) (187 aas; 4 TMSs).

Bacteria
Firmicutes
QueT of Leuconostoc gasicomitatum (D8MFQ0)
*2.A.88.9.3









Uncharacterized protein of 378 aas and 6 TMSs, one in the middle of the N-terminal hydrophilic domain of about 220 aas, and the remaining 5 together in the C-terminal domain. The N-terminal domain is the QueC or ExsB family, where the former is involved in queosine biosynthesis and may be a regulator, while the latter is the trannsmembrane transport protein. This is the only protein in the NCBI protein database with this fusion, so it may be an artifact.

Archaea
Candidatus Lokiarchaeota
UP of Candidatus Korarchaeota archaeon (hot springs metagenome)
*2.A.88.10.1










Putative thiazole transporter, ThiW. (thiazole ECF transporter S component) Regulated by a TPP riboswitch (Rodionov et al. 2009).

Bacteria
Firmicutes
ThiW of Streptococcus pneumoniae (Q97RS0)