Bacterial 2,3-butanediol and acetoin catabolism

A reusable bacterial pathway in which a stereospecific 2,3-butanediol dehydrogenase can supply acetoin to a lipoyl-dependent acetoin-cleaving system. AcoA/AcoB E1 cleaves acetoin and reductively acetylates the AcoC lipoyl arm, AcoC E2 transfers acetyl to coenzyme A, and an AcoL-like or shared E3 reoxidizes the reduced lipoyl arm. The module is species-neutral; concrete proteins below are verified exemplars rather than required orthologs.

MODULE:bacterial_2_3_butanediol_acetoin_catabolismDRAFTCONCRETEMetabolic Pathwaymodules/bacterial_2_3_butanediol_acetoin_catabolism.yaml
PMID:7813883
Molecular characterization of the Pseudomonas putida 2,3-butanediol catabolic pathway.
PpG2 experiments connect an inducible 2,3-butanediol dehydrogenase to AcoA, AcoB, and AcoC in conversion of 2,3-butanediol to central metabolites.
PMID:2061286
Identification and molecular characterization of the Alcaligenes eutrophus H16 aco operon genes involved in acetoin catabolism.
Protein purification establishes alpha2-beta2 AcoA/AcoB E1 architecture, identifies AcoC, and explicitly leaves AcoX function unknown.
PMID:8110297
Identification and molecular characterization of the aco genes encoding the Pelobacter carbinolicus acetoin dehydrogenase enzyme system.
The Pelobacter system identifies separate AcoA, AcoB, AcoC, and AcoL E1, E2, and E3 components and provides a verified E3 exemplar.
file:PSEPK/acoC/acoC-deep-research-openscientist.md
OpenScientist gene research for PSEPK acoC
The report corroborates the locus and E2/lipoyl-domain interpretation; unvalidated structural and regulatory predictions were not promoted to module claims.

AcoX is locus-associated accessory context, not a catalytic part, because its biochemical function remains unknown. Pseudomonas KT2440 does not encode an obvious acoL in PP_0552-PP_0556, so the exact E3 paralog is a residual gap. Completed OpenScientist artifacts were present only for acoC. No gene reports for bdhA, acoA, acoB, or PP_0556 and no generic module or module+pathway+taxon report were found after the completed research attempts; those jobs were not restarted. The curated boundary therefore rests on cached primary literature, GOA/UniProt, and verified cross-taxon exemplars.

5Nodes
4Parts
0Variant Sets
0Variants
4Annotons
3Connections

Derived QC

Recommended-field compliance

5.9% recommended fields populated
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Module deep research

✗ none found

No MODULE:bacterial_2_3_butanediol_acetoin_catabolism deep-research report alongside the module YAML.

Leaf nodes lacking representative members

✓ every leaf node grounds to a representative protein.

Template conformance

✓ every declared conforms_to bundle matches its template motif.

Gene-review completeness (4/10 grounded genes reviewed)

3 complete review(s) · 1 with deep research · 6 missing review · 3 reviewed but lacking deep research

Gene Review Complete Deep research
acoA Q88QD9 ✓ ✓ ✗
acoB Q88QE0 ✓ ✓ ✗
acoC Q88QE1 ✓ ✓ ✓
bdhA Q88QE2 ✓ 4/5 ✗
AcoA (Cupriavidus necator H16) P27745 ✗ — —
AcoB (Cupriavidus necator H16) P27746 ✗ — —
AcoC (Cupriavidus necator H16) P27747 ✗ — —
AcoC (Pseudomonas putida PpG2) Q59695 ✗ — —
Adh (Pseudomonas putida PpG2) Q59696 ✗ — —
AcoL (Pelobacter carbinolicus) Q60154 ✗ — —

Details

Context
bacteriaNCBITaxon:2
Bacterial 2,3-butanediol and acetoin catabolismMetabolic Pathwaybacterial_2_3_butanediol_acetoin_catabolism
Context
bacteriaNCBITaxon:2

Connections

The optional dehydrogenase supplies acetoin to E1.
E1 supplies S-acetyldihydrolipoyl-AcoC to the E2 transfer step.
E2 leaves reduced dihydrolipoyl-AcoC for E3 reoxidation.
Part 1: optional stereospecific 2,3-butanediol oxidation (optional)
2,3-butanediol oxidation to acetoinReactionbutanediol_to_acetoin

Annotons

2,3-butanediol dehydrogenase
bdh_butanediol_dehydrogenase
Participant: Family: bacterial zinc-dependent 2,3-butanediol dehydrogenase family
Family:
bacterial zinc-dependent 2,3-butanediol dehydrogenase family
Representative Members: BdhA (Pseudomonas putida KT2440)UniProtKB:Q88QE2 Adh (Pseudomonas putida PpG2)UniProtKB:Q59696

Function

NAD(P)-linked alcohol dehydrogenase activityGO:0016616
Substrates: 2,3-butanediol NAD(P)+
Products: acetoin NAD(P)H proton

Optional entry reaction. The specific stereoisomer accepted by KT2440 BdhA is unresolved, and other bacterial routes can employ differently stereospecific dehydrogenases.

Part 2: E1 acetoin cleavage and reductive lipoyl acetylation
AcoA/AcoB E1 acetoin cleavageReactionacoab_e1_acetoin_cleavage

Annotons

acetoin-cleaving E1 alpha/beta complex
acoab_e1_complex
Participant: Protein Complex: bacterial acetoin-cleaving E1 alpha2-beta2 complex
Protein Complex:
bacterial acetoin-cleaving E1 alpha2-beta2 complex
Active units:
AcoA E1 alpha subunit
Participant: Family: acetoin-cleaving E1 alpha-subunit family
Family:
acetoin-cleaving E1 alpha-subunit family
Representative Members: AcoA (Pseudomonas putida KT2440)UniProtKB:Q88QD9 AcoA (Cupriavidus necator H16)UniProtKB:P27745
AcoB E1 beta subunit
Participant: Family: acetoin-cleaving E1 beta-subunit family
Family:
acetoin-cleaving E1 beta-subunit familyPANTHER:PTHR43257:SF3
Representative Members: AcoB (Pseudomonas putida KT2440)UniProtKB:Q88QE0 AcoB (Cupriavidus necator H16)UniProtKB:P27746

Function

oxidoreductase activity, acting on an oxo donor with a disulfide acceptorGO:0016624
Substrates: acetoin oxidized lipoyl-AcoC
Products: acetaldehyde S-acetyldihydrolipoyl-AcoC

The TDP-dependent E1 alpha/beta complex cleaves acetoin and transfers the acetyl equivalent to the oxidized lipoyl arm of AcoC. The GO term describes the assembled activity; AcoA and AcoB individually contribute to it.

Part 3: E2 transfer of lipoyl-bound acetyl to coenzyme A
AcoC E2 acetyl transferReactionacoc_e2_acetyl_transfer

Annotons

acetoin-system dihydrolipoyllysine-residue acetyltransferase
acoc_e2
Participant: Family: acetoin-system AcoC E2 family
Family:
acetoin-system AcoC E2 family
Representative Members: AcoC (Pseudomonas putida KT2440)UniProtKB:Q88QE1 AcoC (Pseudomonas putida PpG2)UniProtKB:Q59695 AcoC (Cupriavidus necator H16)UniProtKB:P27747

Function

dihydrolipoyllysine-residue acetyltransferase activityGO:0004742
Substrates: S-acetyldihydrolipoyl-AcoC coenzyme A
Products: dihydrolipoyl-AcoC acetyl-CoA

The lipoyl-bearing E2 transfers acetyl to CoA, producing acetyl-CoA and leaving its lipoyl arm reduced for E3 regeneration.

Part 4: E3 regeneration of the oxidized lipoyl arm
Dihydrolipoyl dehydrogenase regeneration stepReactione3_lipoyl_reoxidation

Annotons

acetoin-system or shared dihydrolipoyl dehydrogenase E3
acol_like_e3
Participant: Ortholog Of: AcoL (Pelobacter carbinolicus)
Gene Product:
AcoL (Pelobacter carbinolicus)UniProtKB:Q60154 Characterized pathway-linked E3 exemplar.
Ortholog Of:
AcoL (Pelobacter carbinolicus)UniProtKB:Q60154
Required Function:
dihydrolipoyl dehydrogenase (NADH) activityGO:0004148

Function

dihydrolipoyl dehydrogenase (NADH) activityGO:0004148
Substrates: dihydrolipoyl-AcoC NAD+
Products: oxidized lipoyl-AcoC NADH proton

E3 closes the lipoyl redox cycle. Some bacteria encode a pathway-linked AcoL; others can recruit a shared dihydrolipoyl dehydrogenase.