betT-I (PP_5061) encodes a predicted multi-pass cytoplasmic-membrane transporter of the betaine/choline/carnitine transporter family. It is the BetT paralog adjacent and divergently oriented to the betIBA choline-oxidation operon. Choline uptake is therefore a plausible substrate assignment, but direct transport measurements and checkable literature evidence that distinguish BetT-I from the other KT2440 BCCT paralogs are unavailable.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0005886 plasma membrane | IEA GO_REF:0000120 | ACCEPT | Summary: Twelve predicted transmembrane helices and the BBCT-family assignment support localization in the bacterial plasma membrane. Reason: Twelve Phobius-predicted transmembrane helices and BCCT-family membership (all characterized BCCT carriers, e.g. E. coli BetT, sit in the cytoplasmic membrane) support plasma-membrane localization. Supporting Evidence: file:PSEPK/betT-I/betT-I-uniprot.txt TRANSMEM 20..38 file:PSEPK/betT-I/betT-I-uniprot.txt DR InterPro; IPR000060; BCCT_transptr. PMID:17322201 the predictions that BetT comprised 12 membrane-spanning regions and that its N- and C-terminal extensions of about 12 and 180 amino acid residues, respectively, were situated in the cytoplasm were confirmed |
| GO:0016020 membrane | IEA GO_REF:0000002 | MODIFY | Summary: Membrane localization is correct but general beside the plasma-membrane row. Reason: Correct but general: plasma membrane (GO:0005886) is accepted on the sibling row. Refined to GO:0005886, as for E. coli BetT. Proposed replacements: plasma membrane Supporting Evidence: file:PSEPK/betT-I/betT-I-uniprot.txt TRANSMEM 20..38 file:PSEPK/betT-I/betT-I-uniprot.txt DR InterPro; IPR000060; BCCT_transptr. |
| GO:0022857 transmembrane transporter activity | IEA GO_REF:0000120 | ACCEPT | Summary: The BCCT-family assignment and predicted membrane topology support transmembrane transporter activity. Reason: Retain the substrate-neutral molecular function. The BCCT family (PTHR30047) and its SF7 subfamily, where BetT-I is classified, carry choline, glycine betaine, ectoine and trimethylamine. Adjacency to betIBA makes choline plausible but does not justify GO:0015220 without a transport assay. Term as precise as the evidence allows. Supporting Evidence: file:PSEPK/betT-I/betT-I-uniprot.txt DR InterPro; IPR000060; BCCT_transptr. file:PSEPK/betT-I/betT-I-uniprot.txt DR NCBIfam; TIGR00842; bcct; 1. |
| GO:0055085 transmembrane transport | IEA GO_REF:0000108 | ACCEPT | Summary: A multi-pass BCCT-family transporter is appropriately annotated to transmembrane transport. Reason: Retain the substrate-neutral process until direct or fully checkable evidence distinguishes the transported substrate. Supporting Evidence: file:PSEPK/betT-I/betT-I-uniprot.txt DR InterPro; IPR000060; BCCT_transptr. file:PSEPK/betT-I/betT-I-uniprot.txt TRANSMEM 20..38 |
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