Finding step nupC for thymidine catabolism in Streptacidiphilus oryzae TH49
No candidates for nupC: thymidine permease NupC
GapMind classifies a step as low confidence even if it does not find any candidates. You can still try to find candidates by using Curated BLAST (which searches the 6-frame translation) or by text search of the annotations (which may indicate weak homology, under 30% identity or 50% coverage, that GapMind does not consider). See the links below.
Definition of step nupC
- Curated sequence P0AFF2: Nucleoside permease NupC; Nucleoside-transport system protein NupC. 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). ADP-glucose is also a substrate of this system. nucleoside:H+ symporter NupC. nucleoside:H+ symporter NupC
- Ignore hits to P39141 when looking for 'other' hits (Nucleoside permease NupC. Pyrimidine-specific nucleoside:H+ symporter, NupC)
- UniProt sequence A0KU05: RecName: Full=Nucleoside permease {ECO:0000256|RuleBase:RU362018}; Flags: Precursor;
- Ignore hits to Q9KPL5 when looking for 'other' hits (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)
- Ignore hits to P33021 when looking for 'other' hits (Putative nucleoside permease NupX. Nucleoside permease NupX. putative nucleoside transporter)
- Comment: A nupC-like protein from Shewanella sp. ANA-3 (Shewana3_1039, A0KU05) is important for utilization of thymidine and other nucleosides. A similar protein from V. cholerae (Q9KPL5) binds uridine and 2'-deoxyuridine and is likely to be a thymidine transporter as well, but this is not proven. The nupC protein from B. subtilis (P39141) was shown to be a uridine transporter (PMID:8550462) and is suspected to be a thymidine transporter as well, so it is ignored. The specificity of E. coli nupX (P33021, also known as yeiJ) seems to be unknown.
Or cluster all characterized nupC proteins
This GapMind analysis is from Sep 24 2021. The underlying query database was built on Sep 17 2021.
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About GapMind
Each pathway is defined by a set of rules based on individual steps or genes. Candidates for each step are identified by using
ublast (a fast alternative to protein BLAST)
against a database of manually-curated proteins (most of which are experimentally characterized) or by using
HMMer with enzyme models (usually from
TIGRFam). Ublast hits may be split across two different proteins.
A candidate for a step is "high confidence" if either:
- ublast finds a hit to a characterized protein at above 40% identity and 80% coverage, and bits >= other bits+10.
- (Hits to curated proteins without experimental data as to their function are never considered high confidence.)
- HMMer finds a hit with 80% coverage of the model, and either other identity < 40 or other coverage < 0.75.
where "other" refers to the best ublast hit to a sequence that is not annotated as performing this step (and is not "ignored").
Otherwise, a candidate is "medium confidence" if either:
- ublast finds a hit at above 40% identity and 70% coverage (ignoring otherBits).
- ublast finds a hit at above 30% identity and 80% coverage, and bits >= other bits.
- HMMer finds a hit (regardless of coverage or other bits).
Other blast hits with at least 50% coverage are "low confidence."
Steps with no high- or medium-confidence candidates may be considered "gaps."
For the typical bacterium that can make all 20 amino acids, there are 1-2 gaps in amino acid biosynthesis pathways.
For diverse bacteria and archaea that can utilize a carbon source, there is a complete
high-confidence catabolic pathway (including a transporter) just 38% of the time, and
there is a complete medium-confidence pathway 63% of the time.
Gaps may be due to:
- our ignorance of proteins' functions,
- omissions in the gene models,
- frame-shift errors in the genome sequence, or
- the organism lacks the pathway.
GapMind relies on the predicted proteins in the genome and does not search the six-frame translation. In most cases, you can search the six-frame translation by clicking on links to Curated BLAST for each step definition (in the per-step page).
For more information, see:
If you notice any errors or omissions in the step descriptions, or any questionable results, please let us know
by Morgan Price, Arkin group, Lawrence Berkeley National Laboratory