4-hydroxybenzoate catabolism in Halomonas desiderata SP1

GapMind for catabolism of small carbon sources

4-hydroxybenzoate catabolism in Halomonas desiderata SP1

Best path

fcbT1, fcbT2, fcbT3, pobA, pcaH, pcaG, pcaB, pcaC, pcaD, catI, catJ, pcaF

Rules

Overview: 4-hydroxybenzoate catabolism in GapMind is based on aerobic oxidation to 3,4-hydroxybenzoate (protocatechuate), followed by meta, ortho, or para cleavage; or reduction to benzoyl-CoA (part of a MetaCyc pathway for phenol degradation, link)

all:

4-hydroxybenzoate-transport, pobA and protocatechuate-degradation
or 4-hydroxybenzoate-transport, hcl, hcrA, hcrB, hcrC and benzoyl-CoA-degradation
Comment: An aerobic route for degradation of 4-hydroxybenzoate involves 4-hydroxybenzoate 3-monooxygenase pobA, which forms protocatechuate (3,4-dihydroxybenzoate). Alternatively, 4-hydroxybenzoate can be activated to 4-hydroxybenzoyl-CoA by hcl and reduced to benzoyl-CoA by hcrABC (link).

protocatechuate-degradation:

ligA, ligB, ligC, ligI, ligU, ligJ and ligK
or pcaH, pcaG, pcaB, pcaC, pcaD and 3-oxoadipate-degradation
or praA and 2-hydroxymuconate-6-semialdehyde-degradation
Comment: In the meta-cleavage pathway (link), the 4,5-dioxygenase ligAB splits protocatechuate to 4-carboxy-2-hydroxymuconate-6-semialdehyde. (In solution, this is in the hemiacetal form.) The semialdehyde is oxidized to 2-pyrone-4,6-dicarboxylate, hydrolyzed to (1E)-4-oxobut-1-ene-1,2,4-tricarboxylate, tautomerized to (1E,3E)-4-hydroxybuta-1,3-diene-1,2,4-tricarboxylate, hydrated to 2-hydroxy-4-oxobutane-1,2,4-tricarboxylate (4-oxalocitramalate), and split by an aldolase to pyruvate and oxaloacetate. In the ortho-cleavage pathway (link), the 3,4-oxygenase pcaHG cleaves the ring to 3-carboxy-cis,cis-muconate, a cycloisomerase forms 4-carboxymuconolactone (2-carboxy-2,5-dihydro-5-oxofuran-2-yl)-acetate), a decarboxylase forms 3-oxoadipate enol lactone ((4,5-dihydro-5-oxofuran-2-yl)-acetate), and a hydrolase forms 3-oxoadipate. In the para-cleavage pathway (link), the 2,3-dioxygenase praA forms (2Z,4Z)-2-hydroxy-5-carboxymuconate-6-semialdehyde, which spontaneously decarboxylates to (2Z,4E)-2-hydroxy-6-oxohexa-2,4-dienoate, also known as 2-hydroxymuconate 6-semialdehyde.

2-hydroxymuconate-6-semialdehyde-degradation:

praB, praC, praD and 2-hydroxypenta-2,4-dienoate-degradation
or xylF and 2-hydroxypenta-2,4-dienoate-degradation
Comment: Dehydrogenase praB forms 2-hydroxymuconate, tautomerase praC forms (3E)-2-oxohex-3-enedioate (2-oxalocrotonate), and decarboxylase praD yields 2-hydroxypenta-2,4-dienoate (HPD). (This series of steps is part of protocatechuate para-cleavage, link, or catechol degradation II, link.) Or, hydrolase xylF forms HPD and formate. (This is part of a MetaCyc pathway for catechol degradation, link.)

benzoyl-CoA-degradation:

benzoyl-CoA-reductase, dch, had, oah, pimB and glutaryl-CoA-degradation
or benzoyl-CoA-reductase, Ch1CoA, badK, badH, badI, pimD, pimC, pimF and glutaryl-CoA-degradation
or boxA, boxB, boxC, boxD, paaF, paaH and paaJ2
Comment: Benzoyl-CoA can be degraded anaerobically (link) by reduction to cyclohex-1,5-diene-1-carbonyl-CoA, followed by hydratase (dch) to 6-hydroxycyclohex-1-ene-1-carbonyl-CoA, a dehydrogenase to 6-oxocyclohex-1-ene-1-carbonyl-CoA, a hydrolase to 2-hydroxy-6-oxocycloheane-1-carbonyl-CoA, a ring-opening hydrolase to 3-hydroxypimeloyl-CoA [the last two steps are both catalyzed by oah], a dehydrogenase to 3-oxopimeloyl-CoA [not linked to sequence and omitted], and an acetyltransferase to glutaryl-CoA and acetyl-CoA. Alternatively, after reduction to cyclohex-1,5-diene-1-carbonyl-CoA, Ch1CoA can further reduce it to cyclohex-1-ene-1-carboxyl-CoA (link), followed by hydration to 2-hydroxy-cyclohexane-1-carbonyl-CoA, oxidation to 2-ketocyclohexane-1-carbonyl-CoA, cleavage by a ring-opening hydrolase to pimeloyl-CoA, oxidation to 2,3-didehydropimeloyl-CoA, hydration to 3-hydroxypimeloyl-C, oxidation to 3-oxopimeloyl-CoA and cleavage by a thiolase to glutaryl-CoA and acetyl-CoA. Benzoyl-CoA degradation can be degraded aerobically (link) by an epoxidase (boxAB) that forms 2,3-epoxy-2-3-dihydrobenzoyl-CoA; a dihydrolase forms cis-3,4-dihydroadipyl-CoA semialdehyde and formate; a dehydrogenase forms cis-3,4-dehydroadipyl-CoA; and an unknown isomerase forms trans-2,3-dehydroadipyl-CoA. This is converted to succinyl-CoA as in the anaerobic pathway (paaF, paaH, and paaJ2).

glutaryl-CoA-degradation: gcdH, ech, fadB and atoB

Comment: In MetaCyc pathway glutaryl-CoA degradation (link), glutaryl-CoA is oxidized to (E)-glutaconyl-CoA and oxidatively decarboxylated to crotonyl-CoA (both by the same enzyme), hydrated to 3-hydroxybutanoyl-CoA, oxidized to acetoacetyl-CoA, and cleaved to two acetyl-CoA.

benzoyl-CoA-reductase:

bcrA, bcrB, bcrC and bcrD
or bamB, bamC, bamD, bamE, bamF, bamG, bamH and bamI
Comment: Benzoyl-CoA reduction is energetically unfavorable. There are two classes of reductases: class I enzymes (bcrABCD) use ATP to drive the reaction, while class II enzymes (bamBCDEFGHI) are thought to us an electron bifurcation. SYN_02587 (Q2LQN9) from Syntrophus aciditrophicus, which can oxidize cyclohex-1,5-diene-1-carbonyl-CoA to benzoyl-CoA, is not included because it seems to lack a mechanism to drive benzoyl-CoA reduction.

2-hydroxypenta-2,4-dienoate-degradation: mhpD, mhpE and acetaldehyde-degradation

Comment: (2Z)-2-hydroxypenta-2,4-dienoate (HPD) is a common intermediate in the aerobic degradation of many aromatic compounds. In MetaCyc pathway 2-hydroxypenta-2,4-dienoate degradation (link), HPD is hydrated to (S)-4-hydroxy-2-oxopentanoate and an aldolase cleaves it to pyruvate and acetaldehyde.

acetaldehyde-degradation:

ald-dh-CoA
or adh and acs
or adh, ackA and pta
Comment: Acetaldehyde can be oxidized to acetyl-CoA, or oxidized to acetate and activated to acetyl-CoA by either acetyl-CoA synthetase (acs) or by acetate kinase (ackA) and phosphate acetyltransferase (pta).

3-oxoadipate-degradation: 3-oxodipate-CoA-transferase and pcaF

Comment: MetaCyc pathway 3-oxoadipate degradation (link) involves activation by CoA (using succinyl-CoA) and a thiolase (succinyltransferase) reaction that splits it to acetyl-CoA and succinyl-CoA.

3-oxodipate-CoA-transferase:

pcaI and pcaJ
or catI and catJ
Comment: Two different types of 3-oxoadipate CoA-transferases (EC 2.8.3.6) are known. They are both heteromeric with each subunit containing a CoA-transferase domain

4-hydroxybenzoate-transport:

pcaK
or fcbT1, fcbT2 and fcbT3
Comment: Transporters were identified using: query: transporter:4-hydroxybenzoate:p-hydroxybenzoate:4-hydroxybenzoic acid:p-hydroxybenzoic acid

72 steps (47 with candidates)

Or see definitions of steps

Step	Description	Best candidate	2nd candidate
fcbT1	tripartite 4-hydroxybenzoate transporter, substrate-binding component FcbT1	BZY95_RS16000	BZY95_RS01830
fcbT2	tripartite 4-hydroxybenzoate transporter, small DctQ-like component FcbT2	BZY95_RS15995
fcbT3	tripartite 4-hydroxybenzoate transporter, large permease subunit FcbT3	BZY95_RS15990	BZY95_RS01820
pobA	4-hydroxybenzoate 3-monooxygenase	BZY95_RS03375	BZY95_RS03400
pcaH	protocatechuate 3,4-dioxygenase, alpha subunit	BZY95_RS03535
pcaG	protocatechuate 3,4-dioxygenase, beta subunit	BZY95_RS03540
pcaB	3-carboxymuconate cycloisomerase	BZY95_RS03585
pcaC	4-carboxymuconolactone decarboxylase	BZY95_RS03565	BZY95_RS01715
pcaD	3-oxoadipate enol-lactone hydrolase	BZY95_RS03565
catI	3-oxoadipate CoA-transferase subunit A (CatI)	BZY95_RS03580
catJ	3-oxoadipate CoA-transferase subunit B (CatJ)	BZY95_RS03575
pcaF	succinyl-CoA:acetyl-CoA C-succinyltransferase	BZY95_RS06835	BZY95_RS03570
Alternative steps:
ackA	acetate kinase	BZY95_RS21880	BZY95_RS12985
acs	acetyl-CoA synthetase, AMP-forming	BZY95_RS21920	BZY95_RS10010
adh	acetaldehyde dehydrogenase (not acylating)	BZY95_RS11785	BZY95_RS16090
ald-dh-CoA	acetaldehyde dehydrogenase, acylating
atoB	acetyl-CoA C-acetyltransferase	BZY95_RS13540	BZY95_RS02365
badH	2-hydroxy-cyclohexanecarboxyl-CoA dehydrogenase	BZY95_RS21565	BZY95_RS20380
badI	2-ketocyclohexanecarboxyl-CoA hydrolase	BZY95_RS21560	BZY95_RS03335
badK	cyclohex-1-ene-1-carboxyl-CoA hydratase	BZY95_RS21575	BZY95_RS06815
bamB	class II benzoyl-CoA reductase, BamB subunit
bamC	class II benzoyl-CoA reductase, BamC subunit
bamD	class II benzoyl-CoA reductase, BamD subunit	BZY95_RS06235
bamE	class II benzoyl-CoA reductase, BamE subunit
bamF	class II benzoyl-CoA reductase, BamF subunit
bamG	class II benzoyl-CoA reductase, BamG subunit
bamH	class II benzoyl-CoA reductase, BamH subunit	BZY95_RS06295
bamI	class II benzoyl-CoA reductase, BamI subunit	BZY95_RS06300
bcrA	ATP-dependent benzoyl-CoA reductase, alpha subunit
bcrB	ATP-dependent benzoyl-CoA reductase, beta subunit
bcrC	ATP-dependent benzoyl-CoA reductase, gamma subunit
bcrD	ATP-dependent benzoyl-CoA reductase, delta subunit
boxA	benzoyl-CoA epoxidase, subunit A
boxB	benzoyl-CoA epoxidase, subunit B
boxC	2,3-epoxybenzoyl-CoA dihydrolase
boxD	3,4-dehydroadipyl-CoA semialdehyde dehydrogenase	BZY95_RS06870
Ch1CoA	cyclohex-1-ene-1-carbonyl-CoA dehydrogenase	BZY95_RS13300	BZY95_RS09860
dch	cyclohexa-1,5-diene-1-carboxyl-CoA hydratase	BZY95_RS17490	BZY95_RS21575
ech	(S)-3-hydroxybutanoyl-CoA hydro-lyase	BZY95_RS21575	BZY95_RS17490
fadB	(S)-3-hydroxybutanoyl-CoA dehydrogenase	BZY95_RS15080	BZY95_RS17495
gcdH	glutaryl-CoA dehydrogenase	BZY95_RS21595	BZY95_RS09155
had	6-hydroxycyclohex-1-ene-1-carbonyl-CoA dehydrogenase	BZY95_RS11780
hcl	4-hydroxybenzoyl-CoA ligase	BZY95_RS08185	BZY95_RS02355
hcrA	4-hydroxybenzoyl-CoA reductase, alpha subunit
hcrB	4-hydroxybenzoyl-CoA reductase, beta subunit
hcrC	4-hydroxybenzoyl-CoA reductase, gamma subunit	BZY95_RS15850	BZY95_RS17660
ligA	protocatechuate 4,5-dioxygenase, alpha subunit
ligB	protocatechuate 4,5-dioxygenase, beta subunit
ligC	2-hydroxy-4-carboxymuconate-6-semialdehyde dehydrogenase
ligI	2-pyrone-4,6-dicarboxylate hydrolase	BZY95_RS14780
ligJ	4-carboxy-2-hydroxymuconate hydratase
ligK	4-oxalocitramalate aldolase	BZY95_RS09195
ligU	4-oxalomesaconate tautomerase	BZY95_RS20070
mhpD	2-hydroxypentadienoate hydratase
mhpE	4-hydroxy-2-oxovalerate aldolase	BZY95_RS06135
oah	6-oxocyclohex-1-ene-1-carbonyl-CoA hydratase
paaF	2,3-dehydroadipyl-CoA hydratase	BZY95_RS06815	BZY95_RS21575
paaH	3-hydroxyadipyl-CoA dehydrogenase	BZY95_RS15080	BZY95_RS06825
paaJ2	3-oxoadipyl-CoA thiolase	BZY95_RS06835	BZY95_RS03570
pcaI	3-oxoadipate CoA-transferase subunit A (PcaI)	BZY95_RS02540
pcaJ	3-oxoadipate CoA-transferase subunit B (PcaJ)	BZY95_RS18550	BZY95_RS02545
pcaK	4-hydroxybenzoate transporter pcaK
pimB	3-oxopimeloyl-CoA:CoA acetyltransferase	BZY95_RS03570	BZY95_RS21635
pimC	pimeloyl-CoA dehydrogenase, small subunit	BZY95_RS09880	BZY95_RS21590
pimD	pimeloyl-CoA dehydrogenase, large subunit	BZY95_RS21585	BZY95_RS09885
pimF	6-carboxyhex-2-enoyl-CoA hydratase	BZY95_RS15080
praA	protocatechuate 2,3-dioxygenase
praB	2-hydroxymuconate 6-semialdehyde dehydrogenase	BZY95_RS10630	BZY95_RS10455
praC	2-hydroxymuconate tautomerase	BZY95_RS17985
praD	2-oxohex-3-enedioate decarboxylase
pta	phosphate acetyltransferase	BZY95_RS21875	BZY95_RS12980
xylF	2-hydroxymuconate semialdehyde hydrolase

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