Finding step xylF for D-xylose catabolism in Sinorhizobium meliloti 1021
3 candidates for xylF: ABC transporter for xylose, substrate binding component xylF
Score | Gene | Description | Similar to | Id. | Cov. | Bits | Other hit | Other id. | Other bits |
hi | SM_b20895 | sugar uptake ABC transporter substrate-binding protein precursor | CVE1 aka ChvE aka ATU2348 aka AGR_C_4267, component of Multiple sugar (arabinose, xylose, galactose, glucose, fucose) putative porter (characterized) | 77% | 100% | 547.4 | Probable sugar binding protein of ABC transporter for pentoses, component of ABC sugar transporter that plays a role in the probiotic benefits through acetate production | 42% | 259.6 |
med | SM_b20902 | sugar uptake ABC transporter substrate-binding protein precursor | D-xylose ABC transporter, periplasmic D-xylose-binding protein (characterized) | 42% | 99% | 252.3 | glucose transporter, periplasmic substrate-binding component | 66% | 439.5 |
med | SMc03813 | periplasmic binding ABC transporter protein | LacI family transcriptional regulator, component of Glucose porter. Also bind xylose (Boucher and Noll 2011). Induced by glucose (Frock et al. 2012). Directly regulated by glucose-responsive regulator GluR (characterized) | 32% | 90% | 150.6 | RhaS, component of Rhamnose porter (Richardson et al., 2004) (Transport activity is dependent on rhamnokinase (RhaK; AAQ92412) activity (Richardson and Oresnik, 2007) This could be an example of group translocation!) | 31% | 88.2 |
Confidence: high confidence medium confidence low confidence
transporter – transporters and PTS systems are shaded because predicting their specificity is particularly challenging.
GapMind searches the predicted proteins for candidates by using ublast (a fast alternative to protein BLAST) to find similarities to characterized proteins or by using HMMer to find similarities to enzyme models (usually from TIGRFams). For alignments to characterized proteins (from ublast), scores of 44 bits correspond to an expectation value (E) of about 0.001.
Also see fitness data for the candidates
Definition of step xylF
- Curated sequence CH_003787: D-xylose ABC transporter, periplasmic D-xylose-binding protein. XylF aka XYLT aka B3566, component of Xylose porter. xylose ABC transporter periplasmic binding protein (EC 7.5.2.13; EC 7.5.2.10). xylose ABC transporter periplasmic binding protein (EC 7.5.2.13)
- Curated sequence A6LW10: D-xylose ABC transporter, periplasmic substrate-binding protein, component of Xylose transporter, XylFGH (XylF (R), 359 aas; XylG (C), 525 aas; XylH (M), 389 aas
- Curated sequence P25548: CVE1 aka ChvE aka ATU2348 aka AGR_C_4267, component of Multiple sugar (arabinose, xylose, galactose, glucose, fucose) putative porter
- Curated sequence G4FGN5: LacI family transcriptional regulator, component of Glucose porter. Also bind xylose (Boucher and Noll 2011). Induced by glucose (Frock et al. 2012). Directly regulated by glucose-responsive regulator GluR
- Ignore hits to P54083 when looking for 'other' hits (Multiple sugar-binding periplasmic protein SbpA; Sugar-binding protein A)
- Comment: T. maritima has a diverged SBP, Tmari_1858 (G4FGN5). Tmari_1858 is sometimes annotated as gluE, and is glucose induced. But the Km for xylose is quite low, so, considered it a xylose transporter as well. Ignore P54083 (sbpA from A. brasilensis), not known if it transports xylose or not; close homolog HSERO_RS05190 is mildly important for fitness during growth on xylose, so, it may transport xylose.
Or cluster all characterized xylF proteins
This GapMind analysis is from Apr 09 2024. The underlying query database was built on Sep 17 2021.
Links
Downloads
Related tools
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