Finding step LAT2 for L-histidine catabolism in Lysobacter daejeonensis GH1-9
No candidates for LAT2: L-histidine transporter
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 LAT2
- Curated sequence Q9WVR6: Large neutral amino acids transporter small subunit 2; L-type amino acid transporter 2; Solute carrier family 7 member 8. L-type neutral amino acid transporter, LAT2 (Na+-independent with broad specificity for all L-isomers of neutral amino acids; preferred substrate: Phe, His, Trp, Ile, Val, Leu, Gln, Cys, Ser; catalyzes obligatory exchange with μM affinities on the outside and mM affinities on the inside [1000x difference]). Both LAT2 and LAT1 (2.A.3.8.1) catalyze uptake of S-nitro-L-cysteine (Li and Whorton, 2005). Also transports thyroid hormones
- Curated sequence O34739: Serine/threonine exchanger SteT. The Ser/Thr exchange transporter (SteT) (also transports aromatic amino acids with lower efficiency) (Reig et al., 2007). The substrate-bound state of SteT shows increased conformational flexibility and kinetic stability, enabling transport of substrate across the cell membrane (Bippes et al. 2009). TMS8 sculpts the substrate-binding site and undergoes conformational changes during the transport cycle of SteT (Bartoccioni et al., 2010). Mutations allow substrate binding but not translocation. Other mutations stabilize the protein and result in higher production levels
- Curated sequence Q26594: The schistosome neutral and cationic amino acid transporter, SPRM1lc (Na+-independent), (takes up phe, arg, lys, ala, gln, his, trp and leu; functions with SPRM1hc (TC# 8.A.9.3.1)
- Curated sequence Q9NA91: Aromatic amino acid exchanger, AAT-9 (Veljkovic et al., 2004b)
Or cluster all characterized LAT2 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