L-phenylalanine catabolism in Xanthobacter autotrophicus Py2

Best path

livF, livG, livH, livM, livJ, ARO8, iorAB, paaA, paaB, paaC, paaE, paaG, paaZ1, paaZ2, paaJ1, paaF, paaH, paaJ2

Rules

Overview: Phenylalanine utilization in GapMind is based on MetaCyc pathway L-phenylalanine degradation I (aerobic, via tyrosine, link), pathway II (anaerobic, via phenylacetaldehyde dehydrogenase, link), degradation via phenylpyruvate:ferredoxin oxidoreductase (PMC3346364), or degradation via phenylacetaldehyde:ferredoxin oxidoreductase (PMID:24214948). (MetaCyc describes additional pathways, but they do not result in carbon incorporation or are not reported in prokaryotes, so they are not included in GapMind.)

• all:
  • phenylalanine-transport, ARO8, phenylpyruvate-fd-oxidoreductase and phenylacetyl-CoA-degradation
  • or phenylalanine-transport, ARO8, phenylpyruvate-decarboxylase, pad-dh and phenylacetate-degradation
  • or phenylalanine-transport, ARO8, phenylpyruvate-decarboxylase, pfor and phenylacetate-degradation
  • or phenylalanine-transport, PAH, PCBD, QDPR and tyrosine-degradation
  • Comment: Phenylalanine can be catabolized via transaminase ARO8, which forms phenylpyruvate (also known as 3-phenyl-2-oxo-propanoate), and phenylpyruvate:ferredoxin oxidoreductase, which forms phenylacetyl-CoA. In the anaerobic pathway, the transaminase ARO8 forms phenylpyruvate, a carboxy-lyase forms phenylacetaldehyde, and a dehydrogenase (pad-dh) forms phenylacetate Or, in a variation on the anaerobic pathway, the phenylacetaldehyde is oxidized to phenylacetate by phenylacetaldehyde:ferredoxin oxidoreductase (pfor). In the aerobic pathway, PAH forms tyrosine and hydroxylates its tetrahydropterin co-substrate; the tetrahydropterin is regenerated by dehydratase PCBD and reductase QDPR.
• phenylpyruvate-fd-oxidoreductase:
  • iorA and iorB
  • or iorAB
  • Comment: This enzyme is usually known as indolepyruvate:ferredoxin oxidoreductase, but it acts on phenylpyruvate as well, forming phenylacetyl-CoA (PMID:8206994). Phenylpyruvate:ferredoxin oxidoreductase has both heterodimeric (iorA/iorB) and fused (iorAB) forms.
• phenylpyruvate-decarboxylase:
  • ARO10
  • or PPDCalpha and PPDCbeta
  • Comment: Phenylpyruvate can be decarboxylated to phenylacetaldehyde by the typical homomeric enzyme, or by a heterodimer reported in Streptomyces virginiae (see PMID:28719183)
• phenylacetyl-CoA-degradation:
  • paaA, paaB, paaC, paaE, paaG, paaZ1, paaZ2, paaJ1, paaF, paaH and paaJ2
  • or phenylacetyl-CoA-dehydrogenase, phenylglyoxylate-dehydrogenase and benzoyl-CoA-degradation
  • Comment: In the aerobic pathway, oxygen-dependent 1,2-epoxidase (PaaABCE) converts phenylacetyl-CoA to 1,2-epoxyphenylacetyl-CoA, which spontaenously rearranges to 2-(oxepinyl)acetyl-CoA; isomerase PaaG forms 2-oxepin-2(3H)-ylideneacetyl-CoA ("oxepin-CoA"); a ring-opening hydrolase forms 3-oxo-5,6-didehydrosuberyl-CoA semialdehyde; a dehydrogenase forms 3-oxo-5,6-didehydrosuberyl-CoA; thiolase PaaJ forms cis-3,4-didehydroadipyl-CoA (and acetyl-CoA); isomerase PaaG forms trans-2,3-didehydroadipyl-CoA; hydratase PaaF forms (3S)-hydroxyadipyl-CoA; dehydrogenase PaaH forms 3-oxoadipyl-CoA, and thiolase PaaJ forms succinyl-CoA and acetyl-CoA. (The role of PaaG is described in PMID:31689071 and differs slightly from MetaCyc.) In the anaerobic pathway, a dehydrogenase forms phenylglyoxyl-CoA, a hydrolase forms phenylglyoxylate (this step is not linked to sequence but is likely provided by the phenylglyoxylyl-CoA dehydrogenase, see PMID:10336636), and another dehydrogenase forms benzoyl-CoA and CO2. In principle, this pathway could occur aerobically, so GapMind includes aerobic pathways for degrading the benzoyl-CoA.
• phenylacetate-degradation: paaK and phenylacetyl-CoA-degradation
  • Comment: Phenylacetate is activated to phenylacetyl-CoA by paaK
• 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).
• phenylglyoxylate-dehydrogenase: padG, padI, padE, padF and padH
• phenylacetyl-CoA-dehydrogenase: padB, padC and padD
• 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.
• tyrosine-degradation: HPD, hmgA, maiA, fahA and acetoacetate-degradation
  • Comment: In pathway I, an aminotransferase (not represented) forms 3-(4-hydroxyphenyl)pyruvate, dioxygenase HPD forms homogentisate, another oxygenase forms 4-maleyl-acetoacetate, an isomerase forms 4-fumaryl-acetoacetate, and a hydrolase yields acetoacetate and fumarate. (Fumarate is part of the TCA cycle so its catabolism is not described.)
• acetoacetate-degradation: acetoacetate-activation and atoB
  • Comment: The acetoacetate is activated to acetoacetyl-CoA, and cleaved by acetyl-CoA acetyltransferase, giving two acetyl-CoA.
• acetoacetate-activation:
  • atoA and atoD
  • or aacS
  • Comment: acetyl-CoA:acetoacetyl-CoA transferase (sometimes given EC 2.8.3.9 or EC 2.8.3.8) or succinyl-CoA:acetoacetyl-CoA transferase (EC 2.8.3.5, also known as 3-oxoacid CoA-transferase) can activate acetoacetate. These have an A and B subunit. Alternatively, an ATP-dependent ligase (aacS) can activate acetoacetate (EC 6.2.1.16).
• phenylalanine-transport:
  • livF, livG, livH, livM and livJ
  • or aroP
  • Comment: Transporters were identified using query: transporter:phenylalanine:L-phenylalanine:phe

76 steps (47 with candidates)

Or see definitions of steps

Step	Description	Best candidate	2nd candidate
livF	L-phenylalanine ABC transporter, ATPase component 1 (LivF)	XAUT_RS19750	XAUT_RS20500
livG	L-phenylalanine ABC transporter, ATPase component 2 (LivG)	XAUT_RS20495	XAUT_RS04455
livH	L-phenylalanine ABC transporter, permease component 1 (LivH)	XAUT_RS19735	XAUT_RS05260
livM	L-phenylalanine ABC transporter, permease component 2 (LivM)	XAUT_RS19740	XAUT_RS04460
livJ	L-phenylalanine ABC transporter, substrate-binding component LivJ/LivK	XAUT_RS19760	XAUT_RS08115
ARO8	L-phenylalanine transaminase	XAUT_RS13770	XAUT_RS06035
iorAB	phenylpyruvate:ferredoxin oxidoreductase, fused IorA/IorB	XAUT_RS01975
paaA	phenylacetyl-CoA 1,2-epoxidase, subunit A	XAUT_RS04485
paaB	phenylacetyl-CoA 1,2-epoxidase, subunit B	XAUT_RS04490
paaC	phenylacetyl-CoA 1,2-epoxidase, subunit C	XAUT_RS04495
paaE	phenylacetyl-CoA 1,2-epoxidase, subunit E	XAUT_RS04505
paaG	1,2-epoxyphenylacetyl-CoA isomerase / 2-(oxepinyl)acetyl-CoA isomerase / didehydroadipyl-CoA isomerase	XAUT_RS04520	XAUT_RS07010
paaZ1	oxepin-CoA hydrolase	XAUT_RS04540	XAUT_RS07010
paaZ2	3-oxo-5,6-didehydrosuberyl-CoA semialdehyde dehydrogenase	XAUT_RS04540	XAUT_RS04525
paaJ1	3-oxo-5,6-dehydrosuberyl-CoA thiolase	XAUT_RS05630	XAUT_RS04530
paaF	2,3-dehydroadipyl-CoA hydratase	XAUT_RS04570	XAUT_RS16635
paaH	3-hydroxyadipyl-CoA dehydrogenase	XAUT_RS04535	XAUT_RS04610
paaJ2	3-oxoadipyl-CoA thiolase	XAUT_RS05630	XAUT_RS04530
Alternative steps:
aacS	acetoacetyl-CoA synthetase	XAUT_RS20600	XAUT_RS14125
ARO10	phenylpyruvate decarboxylase
aroP	L-phenylalanine:H+ symporter AroP
atoA	acetoacetyl-CoA transferase, A subunit	XAUT_RS11815	XAUT_RS05620
atoB	acetyl-CoA C-acetyltransferase	XAUT_RS23630	XAUT_RS15615
atoD	acetoacetyl-CoA transferase, B subunit	XAUT_RS11820	XAUT_RS05615
badH	2-hydroxy-cyclohexanecarboxyl-CoA dehydrogenase	XAUT_RS04590	XAUT_RS06800
badI	2-ketocyclohexanecarboxyl-CoA hydrolase	XAUT_RS04595	XAUT_RS04520
badK	cyclohex-1-ene-1-carboxyl-CoA hydratase	XAUT_RS16635	XAUT_RS04570
bamB	class II benzoyl-CoA reductase, BamB subunit
bamC	class II benzoyl-CoA reductase, BamC subunit
bamD	class II benzoyl-CoA reductase, BamD subunit	XAUT_RS04625
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	XAUT_RS17550	XAUT_RS23440
bamI	class II benzoyl-CoA reductase, BamI subunit	XAUT_RS17545
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	XAUT_RS04540
Ch1CoA	cyclohex-1-ene-1-carbonyl-CoA dehydrogenase	XAUT_RS21625	XAUT_RS11005
dch	cyclohexa-1,5-diene-1-carboxyl-CoA hydratase	XAUT_RS04570	XAUT_RS16635
ech	(S)-3-hydroxybutanoyl-CoA hydro-lyase	XAUT_RS16635	XAUT_RS04570
fadB	(S)-3-hydroxybutanoyl-CoA dehydrogenase	XAUT_RS04535	XAUT_RS04610
fahA	fumarylacetoacetate hydrolase	XAUT_RS16770	XAUT_RS12045
gcdH	glutaryl-CoA dehydrogenase	XAUT_RS23880	XAUT_RS21625
had	6-hydroxycyclohex-1-ene-1-carbonyl-CoA dehydrogenase
hmgA	homogentisate dioxygenase	XAUT_RS16775
HPD	4-hydroxyphenylpyruvate dioxygenase
iorA	phenylpyruvate:ferredoxin oxidoreductase, IorA subunit
iorB	phenylpyruvate:ferredoxin oxidoreductase, IorB subunit
maiA	maleylacetoacetate isomerase	XAUT_RS16765	XAUT_RS07550
oah	6-oxocyclohex-1-ene-1-carbonyl-CoA hydratase	XAUT_RS04595	XAUT_RS16635
paaK	phenylacetate-CoA ligase	XAUT_RS04510	XAUT_RS09365
pad-dh	phenylacetaldehyde dehydrogenase	XAUT_RS13710	XAUT_RS01855
padB	phenylacetyl-CoA dehydrogenase, PadB subunit
padC	phenylacetyl-CoA dehydrogenase, PadC subunit
padD	phenylacetyl-CoA dehydrogenase, PadD subunit
padE	phenylglyoxylate dehydrogenase, gamma subunit
padF	phenylglyoxylate dehydrogenase, delta subunit
padG	phenylglyoxylate dehydrogenase, alpha subunit
padH	phenylglyoxylate dehydrogenase, epsilon subunit	XAUT_RS03990
padI	phenylglyoxylate dehydrogenase, beta subunit
PAH	phenylalanine 4-monooxygenase
PCBD	pterin-4-alpha-carbinoalamine dehydratase	XAUT_RS22960
pfor	phenylacetaldeyde:ferredoxin oxidoreductase
pimB	3-oxopimeloyl-CoA:CoA acetyltransferase	XAUT_RS03140	XAUT_RS22505
pimC	pimeloyl-CoA dehydrogenase, small subunit	XAUT_RS08530
pimD	pimeloyl-CoA dehydrogenase, large subunit	XAUT_RS08535	XAUT_RS06740
pimF	6-carboxyhex-2-enoyl-CoA hydratase	XAUT_RS04535	XAUT_RS04610
PPDCalpha	phenylpyruvate decarboxylase, alpha subunit
PPDCbeta	phenylpyruvate decarboxylase, beta subunit	XAUT_RS20440	XAUT_RS19685
QDPR	6,7-dihydropteridine reductase

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.