L-lactate catabolism in Azospirillum humicireducens SgZ-5

GapMind for catabolism of small carbon sources

L-lactate catabolism in Azospirillum humicireducens SgZ-5

Best path

lctP, lutA, lutB, lutC

Rules

Overview: L-lactate degradation in GapMind is based on L-lactate dehydrogenases or oxidases.

all: L-lactate-transport and L-lactate-degradation
L-lactate-degradation:

L-LDH
or lldE, lldF and lldG
or lutA, lutB and lutC
or DVU3033 and DVU3032
or lctO and acs
or lctO, ackA and pta
Comment: Various L-lactate dehydrogenases are known, with different numbers of subunits; these all form pyruvate. Or, after L-lactate oxidase (lctO) forms acetate, the acetate is activated to acetyl-CoA.

L-lactate-transport:

lctP
or SfMCT
or larD
or mctP
or Shew_2731 and Shew_2732
Comment: Transporters were identified using query: transporter:L-lactate:(S)-lactate:D,L-lactic and prokaryotic lactate transporters were examined as well. Exchangers for lactate/citrate or lactate/malate were ignored.

19 steps (15 with candidates)

Or see definitions of steps

Step	Description	Best candidate	2nd candidate
lctP	L-lactate:H+ symporter LctP or LidP	A6A40_RS13760
lutA	L-lactate dehydrogenase, LutA subunit	A6A40_RS13770
lutB	L-lactate dehydrogenase, LutB subunit	A6A40_RS13775
lutC	L-lactate dehydrogenase, LutC subunit	A6A40_RS13780
Alternative steps:
ackA	acetate kinase	A6A40_RS02540	A6A40_RS29385
acs	acetyl-CoA synthetase, AMP-forming	A6A40_RS10075	A6A40_RS08675
DVU3032	L-lactate dehydrogenase, LutC-like component	A6A40_RS13780
DVU3033	L-lactate dehydrogenase, fused LutA/LutB components	A6A40_RS13775
L-LDH	L-lactate dehydrogenase	A6A40_RS14785	A6A40_RS11670
larD	D,L-lactic acid transporter LarD
lctO	L-lactate oxidase or 2-monooxygenase	A6A40_RS14785	A6A40_RS17405
lldE	L-lactate dehydrogenase, LldE subunit	A6A40_RS13770
lldF	L-lactate dehydrogenase, LldF subunit	A6A40_RS13775
lldG	L-lactate dehydrogenase, LldG subunit
mctP	D,L-lactic acid transporter MctP
pta	phosphate acetyltransferase	A6A40_RS02535	A6A40_RS29930
SfMCT	L-lactate transporter SfMCT	A6A40_RS21605
Shew_2731	L-lactate:Na+ symporter, large component	A6A40_RS11400
Shew_2732	L-lactate:Na+ symporter, small component

Confidence: high confidence medium confidence low confidence
transporter – transporters and PTS systems are shaded because predicting their specificity is particularly challenging.

This GapMind analysis is from Sep 24 2021. The underlying query database was built on Sep 17 2021.

Downloads

Candidates (tab-delimited)
Steps (tab-delimited)
Rules (tab-delimited)
Protein sequences (fasta format)
Organisms (tab-delimited)
SQLite3 databases

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:

the paper from 2019 on GapMind for amino acid biosynthesis
the paper from 2022 on GapMind for carbon sources
the source code
instructions for running GapMind on your computer

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

GapMind for catabolism of small carbon sources