TCDB is operated by the Saier Lab Bioinformatics Group
TCIDNameDomainKingdom/PhylumProtein(s)
*2.A.41.1.1









Pyrimidine nucleoside:H+ symporter, NupC (Craig et al. 1994; Patching et al. 2005). Wild-type NupC had an apparent affinity for uridine of 22.2 +/- 3.7 muM and an apparent binding affinity of 1.8-2.6 mM, and various mutants with alterred properties were isolated and characterized (Sun et al. 2017).

Bacteria
Proteobacteria
NupC of E. coli (P0AFF2)
*2.A.41.1.2









Pyrimidine-specific nucleoside:H+ symporter, NupC
Bacteria
Firmicutes
NupC of Bacillus subtilis
*2.A.41.1.3









The purine nucleoside uptake transporter NupG (YxjA) (Johansen et al., 2003)
Bacteria
Firmicutes
NupG of Bacillus subtilis (P42312)
*2.A.41.2.1









Purine-specific nucleoside:Na+ symporter
Eukaryota
Metazoa
The bile canalicular purine-specific nucleoside:Na+ symporter of Rattus norvegicus (Q62773)
*2.A.41.2.2









Nonspecific nucleoside:Na+ symporter
Eukaryota
Metazoa
The nucleoside:Na+ symporter of Rattus norvegicus (Q62674)
*2.A.41.2.3









Pyrimidine-preferring nucleoside:Na+ symporter, CNT1 (Na+/nucleoside = 2)(transports uridine, gemcitabine and 5'-deoxy-5'-fluorouridine) (Larráyoz et al., 2004)

Eukaryota
Metazoa
SLC28A1 of Homo sapiens
*2.A.41.2.4









Purine nucleoside, uridine, and 2'3'dideoxyinosine cladribrine:Na+ symporter, CNT2 (Na+/nucleoside = 1) (Owen et al., 2006)
Eukaryota
Metazoa
SLC28A2 of Homo sapiens
*2.A.41.2.5









Broadly selective nucleoside:Na+ cotransporter, hfCNT (transports uridine, thymidine, inosine, 3'-azido-3'deoxythymidine, 2'3'dideoxycytidine, and 2'3'dideoxyinosine) (Na+/uridine = 2)
Eukaryota
Metazoa
hfCNT of Eptatretus stouti (Q9UA35)
*2.A.41.2.6









Broad-specificity nucleoside:Na+, H+ and Li+ symporter, hCNT3 (Slc28a3) transports a broad range of both purine and pyrimidine nucleosides as well as anticancer and antiviral nucleoside drugs, but guanosine, 3'azido-3-deoxythymidine and 2',3'-dideoxycytidine, which were substrates with Na+, were not substrates with H+. Thus, both of the two cation-binding sites can apparently bind Na+, but only one can bind H+, and the Na+ and H+ forms transport different ranges of substrates. (Note: Cnt1 and Cnt2 are Na+-specific.) (Smith et al., 2005).  (Na+/nucleoside = 2; Na+ + H+/nucleoside = 2; H+ nucleoside = 1).  The matricellular protein, cysteine-rich angiogenic inducer 61 (CYR61), negatively regulates synthesis of the nucleoside transporters hENT1 and hCNT3, both of which transport the anti-cancer agent, gemcitabine (Hesler et al. 2016). Also probably transports gemcitabine, 3'-azido-3'-deoxythymidine (AZT), ribavirin and 3-deazauridine. Modeling revealed mobility of selected binding site and homotrimer interface residues (Latek 2017).

Eukaryota
Metazoa
CNT3 of Homo sapiens (Q9ERH8)
*2.A.41.2.7









Broad specificity nucleoside:H+ symporter (1:1 stoichiometry). Adenosine, uridine, inosine, and guanosine are transported but not cytidine, thymidine or the nucleobase hypoxanthine (Km range: 15-65 μM). Purine and uridine nucleoside drug analogues including cordycepin (3'-deoxyadenosine) are substrates.

Eukaryota
Fungi
CNT of Candida albicans, (Q874I3)
*2.A.41.2.8









Solute carrier family 28 member 3 (Concentrative Na+-nucleoside cotransporter 3) (CNT 3) (hCNT3).  This protein is distinct from TC# 2.A.41.2.6 (78% identity) although these two proteins are called Slc28a3 and CNT3 and have the same description in UniProt (see 2.A.41.2.6 for a more complete description). 

Eukaryota
Metazoa
SLC28A3 of Homo sapiens
*2.A.41.2.9









Putative pseudouridine transporter, PsuT

Bacteria
Proteobacteria
PsuT of Escherichia coli
*2.A.41.2.10









Nucleoside permease NupX

Bacteria
Proteobacteria
NupX of Escherichia coli
*2.A.41.2.11









Concentrative nucleoside transporter, CNT, of 418 aas and 12 TMSs. A repeat-swapped model of VcCNT predicts that nucleoside transport occurs via a mechanism involving an elevator-like substrate binding domain movement across the membrane (Vergara-Jaque et al. 2015).

Bacteria
Proteobacteria
CNT of Vibrio cholerae