Overview: Tyrosine biosynthesis in GapMind is based on MetaCyc pathways L-tyrosine biosynthesis I via 3-(4-hydroxyphenyl)pyruvate (link), pathway II via L-arogenate (link), pathway III via L-arogenate (link), or pathway IV via phenylalanine (link). Pathway II and III are identical except that different cofactors are used by L-arogenate dehydrogenase; these are not distinguished in GapMind. Pathways I and II/III both involve prephenate; in pathway I, prephenate is oxidized to hydroxyphenylpyruvate before being aminated, while in II/III, prephenate is aminated to arogenate before being oxidized to tyrosine. These alternatives are difficult to distinguish by sequence analysis. MetaCyc describes pathway IV as occuring in metazoa, but it also seems to be the main path to tyrosine in some aerobic bacteria (PMC7311316).
Or see definitions of steps
| Step | Description | Best candidate | 2nd candidate |
|---|---|---|---|
| cmutase | chorismate mutase | Q392_RS09585 | Q392_RS16005 |
| pre-dehydr | prephenate dehydrogenase | Q392_RS09590 | Q392_RS09585 |
| tyrB | tyrosine aminotransferase | Q392_RS20965 | Q392_RS16690 |
| Alternative steps: | |||
| aro-dehydr | arogenate dehydrogenase | Q392_RS09590 | |
| PAH | phenylalanine hydroxylase | Q392_RS19570 | |
| ptransferase | prephenate aminotransferase | Q392_RS14190 | Q392_RS18360 |
Confidence: high confidence medium confidence low confidence
? – known gap: despite the lack of a good candidate for this step, this organism (or a related organism) performs the pathway
This GapMind analysis is from Apr 10 2024. The underlying query database was built on Apr 09 2024.
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:
Otherwise, a candidate is "medium confidence" if either:
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:
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