Finding step acdH for L-isoleucine catabolism in Algoriphagus aquaeductus T4
5 candidates for acdH: (2S)-2-methylbutanoyl-CoA dehydrogenase
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.
Definition of step acdH
- Curated proteins or TIGRFams with EC 1.3.8.5 (search)
- Curated sequence PfGW456L13_2983: Short-chain acyl-CoA dehydrogenase (EC 1.3.8.1)
- Curated sequence 7025618: Branched-chain acyl-CoA dehydrogenase (EC 1.3.99.12)
- Curated sequence MONOMER-17424: short-chain acyl-CoA dehydrogenase monomer (EC 1.3.8.1)
- Ignore hits to GFF2392 when looking for 'other' hits (isobutyryl-CoA dehydrogenase (EC 1.3.8.1))
- Ignore hits to GFF2713 when looking for 'other' hits (isobutyryl-CoA dehydrogenase (EC 1.3.8.5))
- Ignore hits to PfGW456L13_2985 when looking for 'other' hits (isobutyryl-CoA dehydrogenase (EC 1.3.8.5))
- Ignore hits to AO353_25670 when looking for 'other' hits (isobutyryl-CoA dehydrogenase (EC 1.3.8.5))
- Ignore hits to P45857 when looking for 'other' hits (Acyl-CoA dehydrogenase; EC 1.3.99.-)
- Ignore hits to CH_091788 when looking for 'other' hits (acyl-CoA dehydrogenase)
- Comment: EC 1.3.8.5 includes (2S)-2-methylbutanoyl-CoA dehydrogenases and also isobutyryl-CoA dehydrogenases (involved in valine degradation) or sometimes 3-methylbutanoyl-CoA dehydrogenases (involved in leucine degradation, usually given EC 1.3.8.4). Some enzymes act on all three methylacyl-CoA substrates. Other genes are required only for valine degradation and their activity on 2-methylbutanoyl-CoA uncertain, so they are marked ignore. PfGW456L13_2983 and Shewana3_2769 (VIMSS 7025618) and PP_2216 (MONOMER-17424) were annotated with other EC numbers (implying other acyl-CoA substrates) but are involved in isoleucine utilization, so are included. Various isobutyryl-CoA dehydrogenases are ignored (they may well act on 2-methylbutanoyl-CoA as well). P45857 (mmgC from B. subtilis) is part of an operon with methylcitrate cycle genes, and could be involved in isoleucine catabolism, but its biochemical activity is uncertain, so it is ignored, as is the nearly-identical CH_091788.
Or cluster all characterized acdH 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