HMM Summary Page: TIGR00804

Functionnucleoside transporter, NupC family
Trusted Cutoff442.00
Domain Trusted Cutoff442.00
Noise Cutoff200.80
Domain Noise Cutoff200.80
Isology Typesubfamily
HMM Length401
Mainrole CategoryTransport and binding proteins
Subrole CategoryNucleosides, purines and pyrimidines
Gene Ontology TermGO:0005337: nucleoside transmembrane transporter activity molecular_function
GO:0005887: integral to plasma membrane cellular_component
GO:0015858: nucleoside transport biological_process
AuthorPaulsen IT, Saier MH, Loftus BJ
Entry DateJul 7 2000 1:41PM
Last ModifiedFeb 14 2011 3:27PM
CommentThe Concentrative Nucleoside Transporter (CNT) Family (TC 2.A.41) Members of the CNT family mediate nucleoside uptake. In bacteria they are energized by H+ symport, but in mammals they are energized by Na+ symport. The different transporters exhibit differing specificities for nucleosides. The E. coli NupC permease transports all nucleosides (both ribo- and deoxyribonucleosides) except hypoxanthine and guanine nucleosides. The B. subtilis NupC is specific for pyrimidine nucleosides (cytidine and uridine and the corresponding deoxyribonucleosides). The mammalian permease members of the CNT family also exhibit differing specificities. Thus, rats possess at least two NupC homologues, one specific for both purine and pyrimidine nucleosides and one specific for purine nucleosides. At least three paralogues have been characterized from humans. One human homologue(CNT1) transports pyrimidine nucleosides and adenosine, but deoxyadenosine and guanosine are poor substrates of this permease. Another (CNT2) is selective for purine nucleosides. Alteration of just a few amino acyl residues in TMSs 7 and 8 interconverts their specificities.
ReferencesA2 hmmalign SE Ipaulsen AL clustalw_manual
Genome PropertyGenProp0461: utilization of deoxynucleosides (HMM-CLUST)