Bacterial lipoyl-dependent acetoin and stereoisomer-specific butanediol catabolism

Lipoyl-dependent acetoin cleavage produces acetaldehyde and acetyl-CoA through an AcoA/AcoB E1 reaction, AcoC acetyl transfer and E3-mediated carrier regeneration. NAD-dependent R,R/meso oxidation and metal-dependent PQQ-mediated S,S-butanediol oxidation can supply acetoin upstream. The compared bacterial implementations differ in E2 architecture, availability of a dedicated E3 and strength of direct biochemical evidence. Native systems are kept separate; the bacterial envelope does not imply universal conservation.

MODULE:bacterial_2_3_butanediol_acetoin_catabolismCOMPLETECONCRETEMetabolic Pathwaymodules/bacterial_2_3_butanediol_acetoin_catabolism.yaml
PMID:17558661
The bacterial review distinguishes competing acetoin-cleavage accounts and motivates an explicit acetoin-dehydrogenase boundary.
then we discuss the relationship between the two conflicting acetoin cleavage pathways, the enzymes of the acetoin dehydrogenase enzyme system, major genes involved in acetoin degradation, and the CcpA mediated acetoin catabolite repression pathway;
PMID:1898934
Purified native Pelobacter E1, E2 and E3 reconstitute acetoin-dependent CoA-coupled NAD reduction.
The combination of purified Ao:DCPIP OR, DHLTA, and DHLDH in the presence of thiamine pyrophosphate and the substrate acetoin or methylacetoin resulted in a coenzyme A-dependent reduction of NAD.
PMID:20508247
The review distinguishes acetoin cleavage from pyruvate decarboxylation and describes reductive acylation of E2-bound lipoamide.
This intermediate collapses, releasing acetaldehyde and leaving TPP with an activated hydroxyethyl group that is poised to acylate the lipoamide cofactor of the E2 subunit.
PMID:20508247
A pathway-linked E3 varies among species; recruitment of a shared E3 where it is absent is explicitly a hypothesis.
The presence of an E3 subunit encoded in this cluster varies by species ( 256 ), and in cases where it is absent, a common E3 is presumably shared between the AoDH and the α-ketoacid dehydrogenases.
PMID:37644496
Different BDHs account for different stereoisomers; an enzyme-family name does not establish universal substrate specificity.
This was discovered to be due to the simultaneous presence of multiple butanediol dehydrogenases (BDHs) in microorganisms, and AC and BD can be interconverted under BDH catalysis.

The boundary is acetoin cleavage plus the explicitly characterized optional NAD/PQQ entry routes, not acetoin synthesis or downstream acetaldehyde assimilation. AcoX/PP0556 is reviewed as locus-associated context but is not asserted to catalyze a step. Regulatory AcoR and lipoylation biosynthesis remain outside the core. Exact native selectors prevent mixed-species complexes; family descriptors classify proteins rather than asserting substrate-specific function for every family member. PpG2 Adh/AcoC are comparative exemplars, not a completed fifth native route. Scope stays CONCRETE with four native bacterial implementations (KT2440, C. necator H16, Syntrophotalea carbinolica, B. subtilis 168), each a separate variant, because the characterized evidence is per-organism and the E2 and E3 architectures differ; a single species-neutral motif would hide those differences. Family grounding was revised on 2026-11-02: PedE/PedH use PTHR32303:SF20 and AcoB uses PTHR43257:SF3, both verified in PANTHER's member index; the KT2440/PpG2 and H16 AcoC descriptors are grounded on NCBIfam NF011457 alone, because PANTHER scatters these lipoyl/alpha-beta-hydrolase acetoin E2s across three hydrolase families (PTHR43194:SF2, PTHR43798:SF33, PTHR43689:SF8) whose other members are unrelated hydrolases. Those subfamilies were briefly carried in family_terms, which was reverted in review: it required each hydrolase family to adjudicate acetyl transfer, and the only scope the schema offers is subfamily-wide, which would have asserted the E2 activity for 87 non-E2 proteins. Each of the three families is still reviewed, and each records why it makes no acetyl-transfer assertion. The bdhA/Adh and B. subtilis AcoC descriptors assert no family id, because PTHR43161 is heterogeneous and PANTHER and UniProt disagree about O31550. Every PANTHER family a member protein belongs to is nevertheless reviewed under interpro/panther/.

21Nodes
13Parts
2Variant Sets
7Variants
15Annotons
15Connections

Derived QC

Recommended-field compliance

100.0% recommended fields populated

All recommended fields populated.

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

2 leaf node(s) with no concrete protein grounding:

Template conformance

✓ every declared conforms_to bundle matches its template motif.

Function consistency and core coverage

9 gene-function check(s) reflected in core functions · 0 conflict(s) · 6 evidence or coverage gap(s) (24 comparison(s))

Retained noncore functions are reported separately; they do not require promotion to core functions. Support from representative genes does not establish conservation across the whole family. Missing reviews or identifiers leave a claim unverified.

AnnotonParticipantFunctionAssessment
kt_bdh bdhA (PSEPK)
UniProtKB:Q88QE2
Gene 		(R,R)-butanediol dehydrogenase activity
GO:0000721 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
kt_pedE pedE (KT2440)
UniProtKB:Q88JH5
Gene 		PQQ-dependent S,S-butanediol oxidation
GO:0016614 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
kt_pedH pedH (KT2440)
UniProtKB:Q88JH0
Gene 		PQQ-dependent S,S-butanediol oxidation
GO:0016614 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
kt_e1 PROTEIN_COMPLEX
Gene 		oxidoreductase activity, acting on the aldehyde or oxo group of donors, disulfide as acceptor
GO:0016624 		Participant Unchecked
No direct UniProt participant to compare. Abstract selectors and complex-wide activities cannot be inferred from donor or subunit gene reviews.
kt_e2 acoC (PSEPK)
UniProtKB:Q88QE1
Gene 		dihydrolipoyllysine-residue acetyltransferase activity
GO:0004742 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
h16_e1 PROTEIN_COMPLEX
Gene 		oxidoreductase activity, acting on the aldehyde or oxo group of donors, disulfide as acceptor
GO:0016624 		Participant Unchecked
No direct UniProt participant to compare. Abstract selectors and complex-wide activities cannot be inferred from donor or subunit gene reviews.
h16_e2 acoC (CUPNH)
UniProtKB:P27747
Gene 		dihydrolipoyllysine-residue acetyltransferase activity
GO:0004742 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
pc_e1 PROTEIN_COMPLEX
Gene 		oxidoreductase activity, acting on the aldehyde or oxo group of donors, disulfide as acceptor
GO:0016624 		Participant Unchecked
No direct UniProt participant to compare. Abstract selectors and complex-wide activities cannot be inferred from donor or subunit gene reviews.
pc_e2 acoC (SYNCB)
UniProtKB:Q59658
Gene 		dihydrolipoyllysine-residue acetyltransferase activity
GO:0004742 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
pc_e3 acoL (SYNCB)
UniProtKB:Q60154
Gene 		dihydrolipoyl dehydrogenase (NADH) activity
GO:0004148 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
bs_e1 PROTEIN_COMPLEX
Gene 		oxidoreductase activity, acting on the aldehyde or oxo group of donors, disulfide as acceptor
GO:0016624 		Participant Unchecked
No direct UniProt participant to compare. Abstract selectors and complex-wide activities cannot be inferred from donor or subunit gene reviews.
bs_e2 acoC (BACSU)
UniProtKB:O31550
Gene 		dihydrolipoyllysine-residue acetyltransferase activity
GO:0004742 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
bs_e3 acoL (BACSU)
UniProtKB:O34324
Gene 		dihydrolipoyl dehydrogenase (NADH) activity
GO:0004148 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
kt_bdh R,R-butanediol dehydrogenase homologs
Family 		(R,R)-butanediol dehydrogenase activity
GO:0000721 		Family Id Missing
The family has no identifier linking it to a curated family review.
kt_pedE PQQ-dependent alcohol dehydrogenase family
PANTHER:PTHR32303:SF20
Family 		PQQ-dependent S,S-butanediol oxidation
GO:0016614 		Family Supported
Family review supports GO:0052934 for PANTHER:PTHR32303:SF20. Cytochrome c-linked oxidation of primary and secondary alcohols is the function of the characterized SF20 type I alcohol dehydrogenases, whether calcium-dependent (PedE, ExaA) or lanthanide-dependent (PedH, ExaF). It is not safe for SF4, whose glucose, quinate and glycerol dehydrogenases reduce ubiquinone and whose methanol dehydrogenases are the distinct cytochrome cL-linked enzymes, nor for SF10 (BamB). The catalytic metal is not determined by subfamily, so this assessment does not license calcium- or lanthanide-specific claims.
kt_pedH PQQ-dependent alcohol dehydrogenase family
PANTHER:PTHR32303:SF20
Family 		PQQ-dependent S,S-butanediol oxidation
GO:0016614 		Family Supported
Family review supports GO:0052934 for PANTHER:PTHR32303:SF20. Cytochrome c-linked oxidation of primary and secondary alcohols is the function of the characterized SF20 type I alcohol dehydrogenases, whether calcium-dependent (PedE, ExaA) or lanthanide-dependent (PedH, ExaF). It is not safe for SF4, whose glucose, quinate and glycerol dehydrogenases reduce ubiquinone and whose methanol dehydrogenases are the distinct cytochrome cL-linked enzymes, nor for SF10 (BamB). The catalytic metal is not determined by subfamily, so this assessment does not license calcium- or lanthanide-specific claims.
kt_e2 Proteobacterial lipoyl-domain and alpha/beta-hydrolase AcoC proteins
NCBIfam:NF011457
Family 		dihydrolipoyllysine-residue acetyltransferase activity
GO:0004742 		Family Review Missing
No supported structured family review is available for NCBIfam:NF011457.
kt_e3 Native acetoin-compatible dihydrolipoyl dehydrogenase lineage, identity unresolved
Family 		dihydrolipoyl dehydrogenase (NADH) activity
GO:0004148 		Family Id Missing
The family has no identifier linking it to a curated family review.
h16_e2 Proteobacterial lipoyl-domain and alpha/beta-hydrolase AcoC proteins
NCBIfam:NF011457
Family 		dihydrolipoyllysine-residue acetyltransferase activity
GO:0004742 		Family Review Missing
No supported structured family review is available for NCBIfam:NF011457.
h16_e3 Native acetoin-compatible dihydrolipoyl dehydrogenase lineage, identity unresolved
Family 		dihydrolipoyl dehydrogenase (NADH) activity
GO:0004148 		Family Id Missing
The family has no identifier linking it to a curated family review.
pc_e2 Lipoyl-bearing acetoin-system AcoC proteins
PANTHER:PTHR23151:SF90
Family 		dihydrolipoyllysine-residue acetyltransferase activity
GO:0004742 		Family Supported
Family review supports GO:0004742 for PANTHER:PTHR23151:SF90. Catalytic E2 subfamilies, as pyruvate_metabolism asserts on the base family. Human PDHX in SF90 is a member exception.
pc_e3 Acetoin-associated dihydrolipoyl dehydrogenases
PANTHER:PTHR22912:SF151
Family 		dihydrolipoyl dehydrogenase (NADH) activity
GO:0004148 		Family Supported
Family review supports GO:0004148 for PANTHER:PTHR22912:SF151. The E3 subfamilies, not the divergent SthA transhydrogenase. SF219 is included on the basis of its independently mapped AcoL representative, the native sequence-based E3 assignment in PMID:10368162 and the conserved catalytic architecture. This extends chemistry scope, not a requirement that all E3 paralogs serve the same physiological complexes. No new PAINT node is inferred.
bs_e2 Canonical lipoyl E2 acyltransferases of 2-oxoacid dehydrogenase-type complexes
Family 		dihydrolipoyllysine-residue acetyltransferase activity
GO:0004742 		Family Id Missing
The family has no identifier linking it to a curated family review.
bs_e3 Acetoin-associated dihydrolipoyl dehydrogenases
PANTHER:PTHR22912:SF219
Family 		dihydrolipoyl dehydrogenase (NADH) activity
GO:0004148 		Family Supported
Family review supports GO:0004148 for PANTHER:PTHR22912:SF219. The E3 subfamilies, not the divergent SthA transhydrogenase. SF219 is included on the basis of its independently mapped AcoL representative, the native sequence-based E3 assignment in PMID:10368162 and the conserved catalytic architecture. This extends chemistry scope, not a requirement that all E3 paralogs serve the same physiological complexes. No new PAINT node is inferred.

Gene-review completeness (19/19 grounded genes reviewed)

19 complete review(s) · 3 with deep research · 0 missing review · 16 reviewed but lacking deep research

Gene Review Complete Deep research
acoA O31404 ✓ ✓ ✗
acoA P27745 ✓ ✓ ✗
acoA Q57102 ✓ ✓ ✗
acoA Q88QD9 ✓ ✓ ✗
acoB O34591 ✓ ✓ ✗
acoB P27746 ✓ ✓ ✗
acoB Q57041 ✓ ✓ ✗
acoB Q88QE0 ✓ ✓ ✗
acoC O31550 ✓ ✓ ✗
acoC P27747 ✓ ✓ ✗
acoC Q59658 ✓ ✓ ✗
acoC Q59695 ✓ ✓ ✗
acoC Q88QE1 ✓ ✓ ✓
acoL O34324 ✓ ✓ ✗
acoL Q60154 ✓ ✓ ✗
adh Q59696 ✓ ✓ ✗
bdhA Q88QE2 ✓ ✓ ✗
pedE Q88JH5 ✓ ✓ ✓
pedH Q88JH0 ✓ ✓ ✓

Details

Context
BacteriaNCBITaxon:2
Lipoyl-dependent acetoin cleavage with stereoisomer-specific butanediol inputMetabolic Pathwaybacterial_2_3_butanediol_acetoin_catabolism
Context
BacteriaNCBITaxon:2
Variant set: Native bacterial acetoin implementations by taxon, E2 architecture and E3 recruitment (Exactly One)
Pseudomonas putida KT2440 acetoin systemMetabolic Pathwaykt_native_system

Native carbon utilization and locus evidence; optional NAD-BDH and metal-dependent PQQ entry pathways account for the three butanediol stereoisomers. E2 transfer is inferred and the E3 paralog is unknown.

Context
Pseudomonas putida KT2440NCBITaxon:160488
PMID:36482024
The KT2440 pathway has an acoABC component assignment; AcoX remains of unknown function.
The acoX gene codes for a protein of unknown function, while acoABC codes for the E1α, E1β and E2 subunits of the acetoin dehydrogenase complex.
PMID:7813883
PpG2 AcoABC subunit assignments were supported by comparative sequence evidence.
The amino acid sequences deduced from acoA, acoB, and acoC for E1 alpha (M(r) 34639), E1 beta (M(r) 37268), and E2 (M(r) 39613) of the P. putida acetoin cleaving system exhibited striking similarities to those of the corresponding components of the A. eutrophus acetoin cleaving system and of the acetoin dehydrogenase enzyme system of Pelobacter carbinolicus and other bacteria.

Connections

kt_nad_entry -> kt_e1_step Provides Input For
NAD-BDH supplies acetoin; acetoin feeding bypasses all entry enzymes.
PMID:34513815
Purified KT2440 PP0552 catalyzes NAD-linked oxidation of R,R and meso butanediol.
For the oxidative reaction, R,R-BDH can catalyze NAD-dependent dehydrogenation of (2R,3R)-2,3-BDO and meso-2,3-BDO.
PMID:34513815
PP0552 is needed for efficient R,R/meso butanediol utilization but dispensable when acetoin is provided, supporting an optional entry step.
the disruption of pp0552 had no effect on the ability of P. putida KT2440 (Δpp0552) to grow in racemic AC and pyruvate but impaired its ability to utilize meso-2,3-BDO and (2R,3R)-2,3-BDO.
kt_pedH_entry -> kt_e1_step Provides Input For
Conditional periplasmic S,S oxidation supplies acetoin for downstream cleavage.
PMID:34513815
Native double deletion prevents S,S-butanediol use with or without lanthanum, while the three-entry-enzyme deletion can still use acetoin.
Double-knockout strain P. putida KT2440 (ΔpedEΔpedH) was completely unable to utilize (2S,3S)-2,3-BDO both in the presence and absence of La3+ (Figures 5C,D) and there might be no other alcohol dehydrogenase catalyzing dehydrogenation of (2S,3S)-2,3-BDO in the strain. PedE and PedH function redundantly in (2S,3S)-2,3-BDO catabolism, but work under different conditions. The triple-knockout strain P. putida KT2440 (Δpp0552ΔpedEΔpedH) grew normally in AC (Figure 5E) and pyruvate (Figure 5F), while lost growth ability in either stereoisomer of 2,3-BDO (Figures 5A–D). Thus, P. putida KT2440 uses R,R-BDH, PedH, and PedE to utilize different 2,3-BDO stereoisomers.
PMID:34513815
The S,S entry reaction supplies S-acetoin upstream of acetoin cleavage.
PedE and PedH catalyze the irreversible dehydrogenation of (2S,3S)-2,3-BDO into (3S)-AC.
kt_pedE_entry -> kt_e1_step Provides Input For
Conditional periplasmic S,S oxidation supplies acetoin for downstream cleavage.
PMID:34513815
Native double deletion prevents S,S-butanediol use with or without lanthanum, while the three-entry-enzyme deletion can still use acetoin.
Double-knockout strain P. putida KT2440 (ΔpedEΔpedH) was completely unable to utilize (2S,3S)-2,3-BDO both in the presence and absence of La3+ (Figures 5C,D) and there might be no other alcohol dehydrogenase catalyzing dehydrogenation of (2S,3S)-2,3-BDO in the strain. PedE and PedH function redundantly in (2S,3S)-2,3-BDO catabolism, but work under different conditions. The triple-knockout strain P. putida KT2440 (Δpp0552ΔpedEΔpedH) grew normally in AC (Figure 5E) and pyruvate (Figure 5F), while lost growth ability in either stereoisomer of 2,3-BDO (Figures 5A–D). Thus, P. putida KT2440 uses R,R-BDH, PedH, and PedE to utilize different 2,3-BDO stereoisomers.
PMID:34513815
The S,S entry reaction supplies S-acetoin upstream of acetoin cleavage.
PedE and PedH catalyze the irreversible dehydrogenation of (2S,3S)-2,3-BDO into (3S)-AC.
kt_e1_step -> kt_e2_step Provides Input For
E1 supplies the acylated lipoyl intermediate to the E2 transfer reaction.
PMID:36482024
The KT2440 pathway has an acoABC component assignment; AcoX remains of unknown function.
The acoX gene codes for a protein of unknown function, while acoABC codes for the E1α, E1β and E2 subunits of the acetoin dehydrogenase complex.
PMID:7813883
PpG2 AcoABC subunit assignments were supported by comparative sequence evidence.
The amino acid sequences deduced from acoA, acoB, and acoC for E1 alpha (M(r) 34639), E1 beta (M(r) 37268), and E2 (M(r) 39613) of the P. putida acetoin cleaving system exhibited striking similarities to those of the corresponding components of the A. eutrophus acetoin cleaving system and of the acetoin dehydrogenase enzyme system of Pelobacter carbinolicus and other bacteria.
PMID:20508247
The review distinguishes acetoin cleavage from pyruvate decarboxylation and describes reductive acylation of E2-bound lipoamide.
This intermediate collapses, releasing acetaldehyde and leaving TPP with an activated hydroxyethyl group that is poised to acylate the lipoamide cofactor of the E2 subunit.
kt_e2_step -> kt_e3_step Provides Input For
E2 leaves reduced lipoyl carrier for E3 oxidation.
PMID:20508247
A pathway-linked E3 varies among species; recruitment of a shared E3 where it is absent is explicitly a hypothesis.
The presence of an E3 subunit encoded in this cluster varies by species ( 256 ), and in cases where it is absent, a common E3 is presumably shared between the AoDH and the α-ketoacid dehydrogenases.
PMID:1898934
Purified native Pelobacter E1, E2 and E3 reconstitute acetoin-dependent CoA-coupled NAD reduction.
The combination of purified Ao:DCPIP OR, DHLTA, and DHLDH in the presence of thiamine pyrophosphate and the substrate acetoin or methylacetoin resulted in a coenzyme A-dependent reduction of NAD.
kt_e3_step -> kt_e1_step Provides Input For
Oxidized lipoyl carrier returns to E1; this is cofactor recycling, not a second carbon input.
PMID:20508247
A pathway-linked E3 varies among species; recruitment of a shared E3 where it is absent is explicitly a hypothesis.
The presence of an E3 subunit encoded in this cluster varies by species ( 256 ), and in cases where it is absent, a common E3 is presumably shared between the AoDH and the α-ketoacid dehydrogenases.
PMID:20508247
The review distinguishes acetoin cleavage from pyruvate decarboxylation and describes reductive acylation of E2-bound lipoamide.
This intermediate collapses, releasing acetaldehyde and leaving TPP with an activated hydroxyethyl group that is poised to acylate the lipoamide cofactor of the E2 subunit.
Part 1: optional stereoisomer-dependent butanediol entry (optional)
Conditional butanediol entry alternativesMetabolic Pathwaykt_entry
Variant set: Substrate and cofactor-specific entry by butanediol stereoisomer and metal availability (One Or More)
R,R/meso NAD-BDH entryReactionkt_nad_entry

Annotons

NAD-dependent R,R/meso butanediol oxidation
kt_bdh
Participant: Gene Product: bdhA (PSEPK)
Gene Product:
bdhA (PSEPK)UniProtKB:Q88QE2
Family:
R,R-butanediol dehydrogenase homologs No family id is asserted. Both representatives match the CDD butanediol_DH_like model cd08233 ((2R,3R)-2,3-butanediol dehydrogenase), which is the closest family-level grouping. The PANTHER family PTHR43161 (sorbitol dehydrogenase) is reviewed as HETEROGENEOUS, and its SF26 also holds E. coli galactitol-1-phosphate dehydrogenase GatD, so neither grants this activity. PpG2 Adh is a comparative homolog; matched PpG2 cofactor/substrate assays were not established from the accessible 1994 text; specificity here is comparative.
Representative Members: bdhA (PSEPK)UniProtKB:Q88QE2 adh (PSEPU)UniProtKB:Q59696

Function

(R,R)-butanediol dehydrogenase activityGO:0000721
Substrates: (2R,3R)-2,3-butanediol or meso-2,3-butanediol NAD+
Products: acetoin NADH proton

Optional R,R/meso carbon entry. PP0552 accepts R,R and meso substrates and showed no NADP(H)-linked activity in Table 2. The PQQ alternatives handle S,S entry under their metal conditions. Acetoin feeding bypasses all entry enzymes.

PMID:34513815
Purified KT2440 PP0552 catalyzes NAD-linked oxidation of R,R and meso butanediol.
For the oxidative reaction, R,R-BDH can catalyze NAD-dependent dehydrogenation of (2R,3R)-2,3-BDO and meso-2,3-BDO.
PMID:34513815
PP0552 is needed for efficient R,R/meso butanediol utilization but dispensable when acetoin is provided, supporting an optional entry step.
the disruption of pp0552 had no effect on the ability of P. putida KT2440 (Δpp0552) to grow in racemic AC and pyruvate but impaired its ability to utilize meso-2,3-BDO and (2R,3R)-2,3-BDO.
PMID:37644496
Different BDHs account for different stereoisomers; an enzyme-family name does not establish universal substrate specificity.
This was discovered to be due to the simultaneous presence of multiple butanediol dehydrogenases (BDHs) in microorganisms, and AC and BD can be interconverted under BDH catalysis.
pedE conditional S,S entryReactionkt_pedE_entry
Context
Calcium-dependent PedE available; native expression favored under low usable lanthanide conditions.

Annotons

pedE S,S-butanediol oxidation
kt_pedE
Participant: Gene Product: pedE (KT2440)
Gene Product:
pedE (KT2440)UniProtKB:Q88JH5
Family:
PQQ-dependent alcohol dehydrogenase familyPANTHER:PTHR32303:SF20 Broad family membership does not specify S,S-butanediol use, metal preference or native electron partner; these are constrained by the exact target and experiments.
Representative Members: pedE (KT2440)UniProtKB:Q88JH5

Function

PQQ-dependent S,S-butanediol oxidationGO:0016614 The broader CH-OH oxidoreductase class encompasses secondary butanediol oxidation to a ketone. GO:0052934 defines primary alcohol oxidation to an aldehyde and therefore does not name this particular step, although these proteins also oxidize primary alcohols. PMS/DCPIP assays do not identify the native electron-transfer partner. PQQ is an enzyme cofactor, not a diffusible NAD-like stoichiometric substrate.
Substrates: (2S,3S)-2,3-butanediol oxidized electron acceptor; native partner identity unresolved
Products: (3S)-acetoin reduced electron acceptor
Cofactors: pyrroloquinoline quinone calcium ion

Locations

outer membrane-bounded periplasmic spaceGO:0030288

Calcium-dependent PedE available; native expression favored under low usable lanthanide conditions. Native substrate phenotypes and purified quinoprotein chemistry support participation. Protein presence alone is insufficient without metal, expression and electron-transfer competence.

PMID:34513815
Native double deletion prevents S,S-butanediol use with or without lanthanum, while the three-entry-enzyme deletion can still use acetoin.
Double-knockout strain P. putida KT2440 (ΔpedEΔpedH) was completely unable to utilize (2S,3S)-2,3-BDO both in the presence and absence of La3+ (Figures 5C,D) and there might be no other alcohol dehydrogenase catalyzing dehydrogenation of (2S,3S)-2,3-BDO in the strain. PedE and PedH function redundantly in (2S,3S)-2,3-BDO catabolism, but work under different conditions. The triple-knockout strain P. putida KT2440 (Δpp0552ΔpedEΔpedH) grew normally in AC (Figure 5E) and pyruvate (Figure 5F), while lost growth ability in either stereoisomer of 2,3-BDO (Figures 5A–D). Thus, P. putida KT2440 uses R,R-BDH, PedH, and PedE to utilize different 2,3-BDO stereoisomers.
PMID:34513815
The S,S entry reaction supplies S-acetoin upstream of acetoin cleavage.
PedE and PedH catalyze the irreversible dehydrogenation of (2S,3S)-2,3-BDO into (3S)-AC.
PMID:28655819
Purified PedH requires tested lanthanides and PedE is its calcium-dependent counterpart.
enzyme activity on a range of substrates similar to that of its Ca2+-dependent counterpart PedE (PP_2674), including linear and aromatic primary and secondary alcohols, as well as aldehydes, but only in the presence of lanthanide ions, including La3+, Ce3+, Pr3+, Sm3+, or Nd3+
PMID:28655819
Purified activities were measured with PMS/DCPIP artificial electron acceptors; native electron-transfer partner identity is not established by this assay.
500 µM phenazine methosulfate (PMS), 150 µM 2,6-dichlorophenol indophenol (DCPIP), 25 mM imidazole, 1 mM CaCl2 for PedE or 1 µM PrCl3 for PedH, 1 µM PQQ for PedE or 50 µM PQQ for PedH, 12.5 µl of substrate, and 2.5 to 20 µg/ml enzyme.
pedH conditional S,S entryReactionkt_pedH_entry
Context
Usable lanthanide supports PedH catalysis; native expression is favored by lanthanides. La availability in the 2021 growth experiment demonstrates this route, not all lanthanide ions.

Annotons

pedH S,S-butanediol oxidation
kt_pedH
Participant: Gene Product: pedH (KT2440)
Gene Product:
pedH (KT2440)UniProtKB:Q88JH0
Family:
PQQ-dependent alcohol dehydrogenase familyPANTHER:PTHR32303:SF20 Broad family membership does not specify S,S-butanediol use, metal preference or native electron partner; these are constrained by the exact target and experiments.
Representative Members: pedH (KT2440)UniProtKB:Q88JH0

Function

PQQ-dependent S,S-butanediol oxidationGO:0016614 The broader CH-OH oxidoreductase class encompasses secondary butanediol oxidation to a ketone. GO:0052934 defines primary alcohol oxidation to an aldehyde and therefore does not name this particular step, although these proteins also oxidize primary alcohols. PMS/DCPIP assays do not identify the native electron-transfer partner. PQQ is an enzyme cofactor, not a diffusible NAD-like stoichiometric substrate.
Substrates: (2S,3S)-2,3-butanediol oxidized electron acceptor; native partner identity unresolved
Products: (3S)-acetoin reduced electron acceptor
Cofactors: pyrroloquinoline quinone usable trivalent lanthanide

Locations

outer membrane-bounded periplasmic spaceGO:0030288

Usable lanthanide supports PedH catalysis; native expression is favored by lanthanides. La availability in the 2021 growth experiment demonstrates this route, not all lanthanide ions. Native substrate phenotypes and purified quinoprotein chemistry support participation. Protein presence alone is insufficient without metal, expression and electron-transfer competence.

PMID:34513815
Native double deletion prevents S,S-butanediol use with or without lanthanum, while the three-entry-enzyme deletion can still use acetoin.
Double-knockout strain P. putida KT2440 (ΔpedEΔpedH) was completely unable to utilize (2S,3S)-2,3-BDO both in the presence and absence of La3+ (Figures 5C,D) and there might be no other alcohol dehydrogenase catalyzing dehydrogenation of (2S,3S)-2,3-BDO in the strain. PedE and PedH function redundantly in (2S,3S)-2,3-BDO catabolism, but work under different conditions. The triple-knockout strain P. putida KT2440 (Δpp0552ΔpedEΔpedH) grew normally in AC (Figure 5E) and pyruvate (Figure 5F), while lost growth ability in either stereoisomer of 2,3-BDO (Figures 5A–D). Thus, P. putida KT2440 uses R,R-BDH, PedH, and PedE to utilize different 2,3-BDO stereoisomers.
PMID:34513815
The S,S entry reaction supplies S-acetoin upstream of acetoin cleavage.
PedE and PedH catalyze the irreversible dehydrogenation of (2S,3S)-2,3-BDO into (3S)-AC.
PMID:28655819
Purified PedH requires tested lanthanides and PedE is its calcium-dependent counterpart.
enzyme activity on a range of substrates similar to that of its Ca2+-dependent counterpart PedE (PP_2674), including linear and aromatic primary and secondary alcohols, as well as aldehydes, but only in the presence of lanthanide ions, including La3+, Ce3+, Pr3+, Sm3+, or Nd3+
PMID:28655819
Purified activities were measured with PMS/DCPIP artificial electron acceptors; native electron-transfer partner identity is not established by this assay.
500 µM phenazine methosulfate (PMS), 150 µM 2,6-dichlorophenol indophenol (DCPIP), 25 mM imidazole, 1 mM CaCl2 for PedE or 1 µM PrCl3 for PedH, 1 µM PQQ for PedE or 50 µM PQQ for PedH, 12.5 µl of substrate, and 2.5 to 20 µg/ml enzyme.
Part 2: E1 cleavage and reductive lipoyl acetylation
E1 acetoin cleavageReactionkt_e1_step

Annotons

Pseudomonas putida KT2440 acetoin-cleaving E1
kt_e1
Participant: Protein Complex: Pseudomonas putida KT2440 AcoA/AcoB E1 assembly
Protein Complex:
Pseudomonas putida KT2440 AcoA/AcoB E1 assembly Alpha/beta E1. Alpha2 beta2 is directly favored for H16 and is comparative architecture for other implementations; no cross-species subunit combination is asserted.
Active units:
E1 alpha component
Participant: Gene Product: acoA (PSEPK)
Gene Product:
acoA (PSEPK)UniProtKB:Q88QD9
Family:
E1 alpha component familyPANTHER:PTHR11516 Verified broad classification. Its official name does not establish this protein's substrate; the exact protein and source-specific functional evidence constrain this role.
Representative Members: acoA (PSEPK)UniProtKB:Q88QD9
Role: Contributes to assembled E1 activity; neither isolated subunit is asserted sufficient.
PMID:36482024
The KT2440 pathway has an acoABC component assignment; AcoX remains of unknown function.
The acoX gene codes for a protein of unknown function, while acoABC codes for the E1α, E1β and E2 subunits of the acetoin dehydrogenase complex.
PMID:7813883
PpG2 AcoABC subunit assignments were supported by comparative sequence evidence.
The amino acid sequences deduced from acoA, acoB, and acoC for E1 alpha (M(r) 34639), E1 beta (M(r) 37268), and E2 (M(r) 39613) of the P. putida acetoin cleaving system exhibited striking similarities to those of the corresponding components of the A. eutrophus acetoin cleaving system and of the acetoin dehydrogenase enzyme system of Pelobacter carbinolicus and other bacteria.
E1 beta component
Participant: Gene Product: acoB (PSEPK)
Gene Product:
acoB (PSEPK)UniProtKB:Q88QE0
Family:
Acetoin-cleaving E1 beta (AcoB) subfamilyPANTHER:PTHR43257:SF3 Verified broad classification. Its official name does not establish this protein's substrate; the exact protein and source-specific functional evidence constrain this role.
Representative Members: acoB (PSEPK)UniProtKB:Q88QE0
Role: Contributes to assembled E1 activity; neither isolated subunit is asserted sufficient.
PMID:36482024
The KT2440 pathway has an acoABC component assignment; AcoX remains of unknown function.
The acoX gene codes for a protein of unknown function, while acoABC codes for the E1α, E1β and E2 subunits of the acetoin dehydrogenase complex.
PMID:7813883
PpG2 AcoABC subunit assignments were supported by comparative sequence evidence.
The amino acid sequences deduced from acoA, acoB, and acoC for E1 alpha (M(r) 34639), E1 beta (M(r) 37268), and E2 (M(r) 39613) of the P. putida acetoin cleaving system exhibited striking similarities to those of the corresponding components of the A. eutrophus acetoin cleaving system and of the acetoin dehydrogenase enzyme system of Pelobacter carbinolicus and other bacteria.

Function

oxidoreductase activity, acting on the aldehyde or oxo group of donors, disulfide as acceptorGO:0016624
Substrates: acetoin oxidized lipoyl-AcoC
Products: acetaldehyde S-acetyldihydrolipoyl-AcoC

TPP-dependent cleavage releases acetaldehyde and reductively acetylates the lipoyl carrier. GO:0016624 names the assembled physiological redox class. Acetoin dehydrogenase (NAD+) GO:0019152 instead names acetoin/diacetyl interconversion and is not used. DCPIP assay activity is distinguished from native lipoyl chemistry.

PMID:36482024
The KT2440 pathway has an acoABC component assignment; AcoX remains of unknown function.
The acoX gene codes for a protein of unknown function, while acoABC codes for the E1α, E1β and E2 subunits of the acetoin dehydrogenase complex.
PMID:7813883
PpG2 AcoABC subunit assignments were supported by comparative sequence evidence.
The amino acid sequences deduced from acoA, acoB, and acoC for E1 alpha (M(r) 34639), E1 beta (M(r) 37268), and E2 (M(r) 39613) of the P. putida acetoin cleaving system exhibited striking similarities to those of the corresponding components of the A. eutrophus acetoin cleaving system and of the acetoin dehydrogenase enzyme system of Pelobacter carbinolicus and other bacteria.
PMID:20508247
The review distinguishes acetoin cleavage from pyruvate decarboxylation and describes reductive acylation of E2-bound lipoamide.
This intermediate collapses, releasing acetaldehyde and leaving TPP with an activated hydroxyethyl group that is poised to acylate the lipoamide cofactor of the E2 subunit.
Part 3: E2 acetyl transfer to CoA
E2 acetyl transferReactionkt_e2_step

Annotons

Pseudomonas putida KT2440 AcoC acetyl transfer
kt_e2
Participant: Gene Product: acoC (PSEPK)
Gene Product:
acoC (PSEPK)UniProtKB:Q88QE1
Family:
Proteobacterial lipoyl-domain and alpha/beta-hydrolase AcoC proteinsNCBIfam:NF011457 These closely related AcoC proteins carry a lipoyl domain and alpha/beta-hydrolase domain. PANTHER splits them between broad hydrolase families (KT2440 in PTHR43194:SF2, PpG2 in PTHR43798:SF33); neither describes this E2, and both subfamilies are dominated by unrelated hydrolases, so neither is asserted as a family term here. The grounding is NCBIfam NF011457 (PRK14875), which groups the lipoyl/alpha-beta-hydrolase acetoin E2s, including the H16 protein. Both PANTHER subfamilies are reviewed, and each review records why it makes no acetyl-transfer assertion. No canonical E2 fold is asserted. The E2 chemistry is a curated comparative assignment, not a purified KT2440/PpG2 transfer measurement.
Representative Members: acoC (PSEPK)UniProtKB:Q88QE1 acoC (PSEPU)UniProtKB:Q59695

Function

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

Transfers lipoyl-bound acetyl to CoA. Pelobacter has purified component/reconstitution support. H16 and Pseudomonas carry a distinct alpha/beta-hydrolase architecture and their exact E2 chemistry remains a curated inference. Bacillus has canonical E2 motifs and native pathway evidence; no isolated Bacillus transfer assay is claimed.

PMID:36482024
The KT2440 pathway has an acoABC component assignment; AcoX remains of unknown function.
The acoX gene codes for a protein of unknown function, while acoABC codes for the E1α, E1β and E2 subunits of the acetoin dehydrogenase complex.
PMID:7813883
PpG2 AcoABC subunit assignments were supported by comparative sequence evidence.
The amino acid sequences deduced from acoA, acoB, and acoC for E1 alpha (M(r) 34639), E1 beta (M(r) 37268), and E2 (M(r) 39613) of the P. putida acetoin cleaving system exhibited striking similarities to those of the corresponding components of the A. eutrophus acetoin cleaving system and of the acetoin dehydrogenase enzyme system of Pelobacter carbinolicus and other bacteria.
PMID:20508247
The review distinguishes acetoin cleavage from pyruvate decarboxylation and describes reductive acylation of E2-bound lipoamide.
This intermediate collapses, releasing acetaldehyde and leaving TPP with an activated hydroxyethyl group that is poised to acylate the lipoamide cofactor of the E2 subunit.
Part 4: E3 lipoyl redox regeneration
E3 lipoyl reoxidationReactionkt_e3_step

Annotons

Pseudomonas putida KT2440 lipoyl redox regeneration
kt_e3
Participant: Any With Function: Native acetoin-compatible dihydrolipoyl dehydrogenase lineage, identity unresolved
Family:
Native acetoin-compatible dihydrolipoyl dehydrogenase lineage, identity unresolved No concrete native E3 is assigned. Cross-species AcoL proteins cannot fill this unresolved role; generic lipoamide dehydrogenase annotation alone does not establish compatibility with native AcoC.
Required Function:
dihydrolipoyl dehydrogenase (NADH) activityGO:0004148
Taxon:
Pseudomonas putida KT2440NCBITaxon:160488
Unresolved native E3 role, requiring both lipoyl redox chemistry and demonstrated participation with this strain's AcoABC. It remains unmet in protein-presence checks.

Function

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

Regenerates the oxidized lipoyl carrier. AcoL is experimentally linked to Pelobacter and inferred from sequence/locus in Bacillus; the KT2440 and H16 native protein identities remain unassigned.

PMID:20508247
A pathway-linked E3 varies among species; recruitment of a shared E3 where it is absent is explicitly a hypothesis.
The presence of an E3 subunit encoded in this cluster varies by species ( 256 ), and in cases where it is absent, a common E3 is presumably shared between the AoDH and the α-ketoacid dehydrogenases.
Cupriavidus necator H16 acetoin systemMetabolic Pathwayh16_native_system

Purified native E1 and fast-migrating AcoC protein; E2 chemistry is inferred and the E3 paralog remains unassigned.

Context
Cupriavidus necator H16NCBITaxon:381666
PMID:2061286
Native H16 E1 purification supports an alpha/beta assembly; alpha2 beta2 stoichiometry is the authors' favored interpretation.
Ao:DCPIP OR consisted of alpha and beta subunits (Mrs, 35,500 and 36,000, respectively), and a tetrameric alpha 2 beta 2 structure was most likely for the native protein.

Connections

h16_e1_step -> h16_e2_step Provides Input For
E1 supplies the acylated lipoyl intermediate to the E2 transfer reaction.
PMID:2061286
The H16 AcoC E2 assignment rests on sequence homology of the purified fast-migrating protein, rather than a gene-specific acetyltransferase assay in the accessible abstract.
whereas those deduced from acoC for FMP (Mr, 38,941) revealed homology to the dihydrolipoamide acetyltransferase of Escherichia coli.
PMID:20508247
The review distinguishes acetoin cleavage from pyruvate decarboxylation and describes reductive acylation of E2-bound lipoamide.
This intermediate collapses, releasing acetaldehyde and leaving TPP with an activated hydroxyethyl group that is poised to acylate the lipoamide cofactor of the E2 subunit.
h16_e2_step -> h16_e3_step Provides Input For
E2 leaves reduced lipoyl carrier for E3 oxidation.
PMID:20508247
A pathway-linked E3 varies among species; recruitment of a shared E3 where it is absent is explicitly a hypothesis.
The presence of an E3 subunit encoded in this cluster varies by species ( 256 ), and in cases where it is absent, a common E3 is presumably shared between the AoDH and the α-ketoacid dehydrogenases.
PMID:1898934
Purified native Pelobacter E1, E2 and E3 reconstitute acetoin-dependent CoA-coupled NAD reduction.
The combination of purified Ao:DCPIP OR, DHLTA, and DHLDH in the presence of thiamine pyrophosphate and the substrate acetoin or methylacetoin resulted in a coenzyme A-dependent reduction of NAD.
h16_e3_step -> h16_e1_step Provides Input For
Oxidized lipoyl carrier returns to E1; this is cofactor recycling, not a second carbon input.
PMID:20508247
A pathway-linked E3 varies among species; recruitment of a shared E3 where it is absent is explicitly a hypothesis.
The presence of an E3 subunit encoded in this cluster varies by species ( 256 ), and in cases where it is absent, a common E3 is presumably shared between the AoDH and the α-ketoacid dehydrogenases.
PMID:20508247
The review distinguishes acetoin cleavage from pyruvate decarboxylation and describes reductive acylation of E2-bound lipoamide.
This intermediate collapses, releasing acetaldehyde and leaving TPP with an activated hydroxyethyl group that is poised to acylate the lipoamide cofactor of the E2 subunit.
Part 2: E1 cleavage and reductive lipoyl acetylation
E1 acetoin cleavageReactionh16_e1_step

Annotons

Cupriavidus necator H16 acetoin-cleaving E1
h16_e1
Participant: Protein Complex: Cupriavidus necator H16 AcoA/AcoB E1 assembly
Protein Complex:
Cupriavidus necator H16 AcoA/AcoB E1 assembly Alpha/beta E1. Alpha2 beta2 is directly favored for H16 and is comparative architecture for other implementations; no cross-species subunit combination is asserted.
Active units:
E1 alpha component
Participant: Gene Product: acoA (CUPNH)
Gene Product:
acoA (CUPNH)UniProtKB:P27745
Family:
E1 alpha component familyPANTHER:PTHR11516 Verified broad classification. Its official name does not establish this protein's substrate; the exact protein and source-specific functional evidence constrain this role.
Representative Members: acoA (CUPNH)UniProtKB:P27745
Role: Contributes to assembled E1 activity; neither isolated subunit is asserted sufficient.
PMID:2061286
Native H16 E1 purification supports an alpha/beta assembly; alpha2 beta2 stoichiometry is the authors' favored interpretation.
Ao:DCPIP OR consisted of alpha and beta subunits (Mrs, 35,500 and 36,000, respectively), and a tetrameric alpha 2 beta 2 structure was most likely for the native protein.
E1 beta component
Participant: Gene Product: acoB (CUPNH)
Gene Product:
acoB (CUPNH)UniProtKB:P27746
Family:
Acetoin-cleaving E1 beta (AcoB) subfamilyPANTHER:PTHR43257:SF3 Verified broad classification. Its official name does not establish this protein's substrate; the exact protein and source-specific functional evidence constrain this role.
Representative Members: acoB (CUPNH)UniProtKB:P27746
Role: Contributes to assembled E1 activity; neither isolated subunit is asserted sufficient.
PMID:2061286
Native H16 E1 purification supports an alpha/beta assembly; alpha2 beta2 stoichiometry is the authors' favored interpretation.
Ao:DCPIP OR consisted of alpha and beta subunits (Mrs, 35,500 and 36,000, respectively), and a tetrameric alpha 2 beta 2 structure was most likely for the native protein.

Function

oxidoreductase activity, acting on the aldehyde or oxo group of donors, disulfide as acceptorGO:0016624
Substrates: acetoin oxidized lipoyl-AcoC
Products: acetaldehyde S-acetyldihydrolipoyl-AcoC

TPP-dependent cleavage releases acetaldehyde and reductively acetylates the lipoyl carrier. GO:0016624 names the assembled physiological redox class. Acetoin dehydrogenase (NAD+) GO:0019152 instead names acetoin/diacetyl interconversion and is not used. DCPIP assay activity is distinguished from native lipoyl chemistry.

PMID:2061286
Native H16 E1 purification supports an alpha/beta assembly; alpha2 beta2 stoichiometry is the authors' favored interpretation.
Ao:DCPIP OR consisted of alpha and beta subunits (Mrs, 35,500 and 36,000, respectively), and a tetrameric alpha 2 beta 2 structure was most likely for the native protein.
PMID:20508247
The review distinguishes acetoin cleavage from pyruvate decarboxylation and describes reductive acylation of E2-bound lipoamide.
This intermediate collapses, releasing acetaldehyde and leaving TPP with an activated hydroxyethyl group that is poised to acylate the lipoamide cofactor of the E2 subunit.
Part 3: E2 acetyl transfer to CoA
E2 acetyl transferReactionh16_e2_step

Annotons

Cupriavidus necator H16 AcoC acetyl transfer
h16_e2
Participant: Gene Product: acoC (CUPNH)
Gene Product:
acoC (CUPNH)UniProtKB:P27747
Family:
Proteobacterial lipoyl-domain and alpha/beta-hydrolase AcoC proteinsNCBIfam:NF011457 H16 AcoC matches NCBIfam NF011457 (PRK14875), the lipoyl/alpha-beta-hydrolase acetoin E2 group, which is its grounding. Its PANTHER placement (PTHR43689:SF8, a heterogeneous hydrolase subfamily) is reviewed but not asserted here, because that subfamily's other members are MhpC-type and epoxide hydrolases and it does not describe the E2 role. The exact protein and source-specific evidence constrain the acetyltransferase assignment.
Representative Members: acoC (CUPNH)UniProtKB:P27747

Function

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

Transfers lipoyl-bound acetyl to CoA. Pelobacter has purified component/reconstitution support. H16 and Pseudomonas carry a distinct alpha/beta-hydrolase architecture and their exact E2 chemistry remains a curated inference. Bacillus has canonical E2 motifs and native pathway evidence; no isolated Bacillus transfer assay is claimed.

PMID:2061286
The H16 AcoC E2 assignment rests on sequence homology of the purified fast-migrating protein, rather than a gene-specific acetyltransferase assay in the accessible abstract.
whereas those deduced from acoC for FMP (Mr, 38,941) revealed homology to the dihydrolipoamide acetyltransferase of Escherichia coli.
PMID:20508247
The review distinguishes acetoin cleavage from pyruvate decarboxylation and describes reductive acylation of E2-bound lipoamide.
This intermediate collapses, releasing acetaldehyde and leaving TPP with an activated hydroxyethyl group that is poised to acylate the lipoamide cofactor of the E2 subunit.
Part 4: E3 lipoyl redox regeneration
E3 lipoyl reoxidationReactionh16_e3_step

Annotons

Cupriavidus necator H16 lipoyl redox regeneration
h16_e3
Participant: Any With Function: Native acetoin-compatible dihydrolipoyl dehydrogenase lineage, identity unresolved
Family:
Native acetoin-compatible dihydrolipoyl dehydrogenase lineage, identity unresolved No concrete native E3 is assigned. Cross-species AcoL proteins cannot fill this unresolved role; generic lipoamide dehydrogenase annotation alone does not establish compatibility with native AcoC.
Required Function:
dihydrolipoyl dehydrogenase (NADH) activityGO:0004148
Taxon:
Cupriavidus necator H16NCBITaxon:381666
Unresolved native E3 role, requiring both lipoyl redox chemistry and demonstrated participation with this strain's AcoABC. It remains unmet in protein-presence checks.

Function

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

Regenerates the oxidized lipoyl carrier. AcoL is experimentally linked to Pelobacter and inferred from sequence/locus in Bacillus; the KT2440 and H16 native protein identities remain unassigned.

PMID:20508247
A pathway-linked E3 varies among species; recruitment of a shared E3 where it is absent is explicitly a hypothesis.
The presence of an E3 subunit encoded in this cluster varies by species ( 256 ), and in cases where it is absent, a common E3 is presumably shared between the AoDH and the α-ketoacid dehydrogenases.
Syntrophotalea carbinolica (historical Pelobacter carbinolicus) acetoin systemMetabolic Pathwaypc_native_system

Purified native components reconstitute the pathway. Historical sequence records are species-level taxon 19; the source strain is Gra Bd 1.

Context
Syntrophotalea carbinolicaNCBITaxon:19
PMID:1898934
Purified native Pelobacter E1, E2 and E3 reconstitute acetoin-dependent CoA-coupled NAD reduction.
The combination of purified Ao:DCPIP OR, DHLTA, and DHLDH in the presence of thiamine pyrophosphate and the substrate acetoin or methylacetoin resulted in a coenzyme A-dependent reduction of NAD.
PMID:8110297
N-terminal sequences link the purified Pelobacter components to the acoABCL genes.
Use of oligonucleotide probes, which were deduced from the N-terminal sequences of the purified enzyme components, identified the structural genes for the alpha and beta subunits of E1 (acetoin:2,6-dichlorophenolindophenol oxidoreductase), E2 (dihydrolipoamide acetyltransferase), and E3 (dihydrolipoamide dehydrogenase) of the Pelobacter carbinolicus acetoin dehydrogenase enzyme system, which were designated acoA, acoB, acoC, and acoL, respectively.

Connections

pc_e1_step -> pc_e2_step Provides Input For
E1 supplies the acylated lipoyl intermediate to the E2 transfer reaction.
PMID:8110297
N-terminal sequences link the purified Pelobacter components to the acoABCL genes.
Use of oligonucleotide probes, which were deduced from the N-terminal sequences of the purified enzyme components, identified the structural genes for the alpha and beta subunits of E1 (acetoin:2,6-dichlorophenolindophenol oxidoreductase), E2 (dihydrolipoamide acetyltransferase), and E3 (dihydrolipoamide dehydrogenase) of the Pelobacter carbinolicus acetoin dehydrogenase enzyme system, which were designated acoA, acoB, acoC, and acoL, respectively.
PMID:1898934
Purified native Pelobacter E1, E2 and E3 reconstitute acetoin-dependent CoA-coupled NAD reduction.
The combination of purified Ao:DCPIP OR, DHLTA, and DHLDH in the presence of thiamine pyrophosphate and the substrate acetoin or methylacetoin resulted in a coenzyme A-dependent reduction of NAD.
PMID:20508247
The review distinguishes acetoin cleavage from pyruvate decarboxylation and describes reductive acylation of E2-bound lipoamide.
This intermediate collapses, releasing acetaldehyde and leaving TPP with an activated hydroxyethyl group that is poised to acylate the lipoamide cofactor of the E2 subunit.
pc_e2_step -> pc_e3_step Provides Input For
E2 leaves reduced lipoyl carrier for E3 oxidation.
PMID:1898934
Purified native Pelobacter E3 uses NAD(H), supporting its redox regeneration role.
DHLDH had a native Mr of 110,000, consisted of two identical subunits of Mr 54,000, and reacted only with NAD(H) as a coenzyme.
PMID:8110297
N-terminal sequences link the purified Pelobacter components to the acoABCL genes.
Use of oligonucleotide probes, which were deduced from the N-terminal sequences of the purified enzyme components, identified the structural genes for the alpha and beta subunits of E1 (acetoin:2,6-dichlorophenolindophenol oxidoreductase), E2 (dihydrolipoamide acetyltransferase), and E3 (dihydrolipoamide dehydrogenase) of the Pelobacter carbinolicus acetoin dehydrogenase enzyme system, which were designated acoA, acoB, acoC, and acoL, respectively.
PMID:1898934
Purified native Pelobacter E1, E2 and E3 reconstitute acetoin-dependent CoA-coupled NAD reduction.
The combination of purified Ao:DCPIP OR, DHLTA, and DHLDH in the presence of thiamine pyrophosphate and the substrate acetoin or methylacetoin resulted in a coenzyme A-dependent reduction of NAD.
pc_e3_step -> pc_e1_step Provides Input For
Oxidized lipoyl carrier returns to E1; this is cofactor recycling, not a second carbon input.
PMID:1898934
Purified native Pelobacter E3 uses NAD(H), supporting its redox regeneration role.
DHLDH had a native Mr of 110,000, consisted of two identical subunits of Mr 54,000, and reacted only with NAD(H) as a coenzyme.
PMID:8110297
N-terminal sequences link the purified Pelobacter components to the acoABCL genes.
Use of oligonucleotide probes, which were deduced from the N-terminal sequences of the purified enzyme components, identified the structural genes for the alpha and beta subunits of E1 (acetoin:2,6-dichlorophenolindophenol oxidoreductase), E2 (dihydrolipoamide acetyltransferase), and E3 (dihydrolipoamide dehydrogenase) of the Pelobacter carbinolicus acetoin dehydrogenase enzyme system, which were designated acoA, acoB, acoC, and acoL, respectively.
PMID:20508247
The review distinguishes acetoin cleavage from pyruvate decarboxylation and describes reductive acylation of E2-bound lipoamide.
This intermediate collapses, releasing acetaldehyde and leaving TPP with an activated hydroxyethyl group that is poised to acylate the lipoamide cofactor of the E2 subunit.
Part 2: E1 cleavage and reductive lipoyl acetylation
E1 acetoin cleavageReactionpc_e1_step

Annotons

Syntrophotalea carbinolica (historical Pelobacter carbinolicus) acetoin-cleaving E1
pc_e1
Participant: Protein Complex: Syntrophotalea carbinolica (historical Pelobacter carbinolicus) AcoA/AcoB E1 assembly
Protein Complex:
Syntrophotalea carbinolica (historical Pelobacter carbinolicus) AcoA/AcoB E1 assembly Alpha/beta E1. Alpha2 beta2 is directly favored for H16 and is comparative architecture for other implementations; no cross-species subunit combination is asserted.
Active units:
E1 alpha component
Participant: Gene Product: acoA (SYNCB)
Gene Product:
acoA (SYNCB)UniProtKB:Q57102
Family:
E1 alpha component familyPANTHER:PTHR11516 Verified broad classification. Its official name does not establish this protein's substrate; the exact protein and source-specific functional evidence constrain this role.
Representative Members: acoA (SYNCB)UniProtKB:Q57102
Role: Contributes to assembled E1 activity; neither isolated subunit is asserted sufficient.
PMID:1898934
Purified native Pelobacter E1, E2 and E3 reconstitute acetoin-dependent CoA-coupled NAD reduction.
The combination of purified Ao:DCPIP OR, DHLTA, and DHLDH in the presence of thiamine pyrophosphate and the substrate acetoin or methylacetoin resulted in a coenzyme A-dependent reduction of NAD.
PMID:8110297
N-terminal sequences link the purified Pelobacter components to the acoABCL genes.
Use of oligonucleotide probes, which were deduced from the N-terminal sequences of the purified enzyme components, identified the structural genes for the alpha and beta subunits of E1 (acetoin:2,6-dichlorophenolindophenol oxidoreductase), E2 (dihydrolipoamide acetyltransferase), and E3 (dihydrolipoamide dehydrogenase) of the Pelobacter carbinolicus acetoin dehydrogenase enzyme system, which were designated acoA, acoB, acoC, and acoL, respectively.
E1 beta component
Participant: Gene Product: acoB (SYNCB)
Gene Product:
acoB (SYNCB)UniProtKB:Q57041
Family:
Acetoin-cleaving E1 beta (AcoB) subfamilyPANTHER:PTHR43257:SF3 Verified broad classification. Its official name does not establish this protein's substrate; the exact protein and source-specific functional evidence constrain this role.
Representative Members: acoB (SYNCB)UniProtKB:Q57041
Role: Contributes to assembled E1 activity; neither isolated subunit is asserted sufficient.
PMID:1898934
Purified native Pelobacter E1, E2 and E3 reconstitute acetoin-dependent CoA-coupled NAD reduction.
The combination of purified Ao:DCPIP OR, DHLTA, and DHLDH in the presence of thiamine pyrophosphate and the substrate acetoin or methylacetoin resulted in a coenzyme A-dependent reduction of NAD.
PMID:8110297
N-terminal sequences link the purified Pelobacter components to the acoABCL genes.
Use of oligonucleotide probes, which were deduced from the N-terminal sequences of the purified enzyme components, identified the structural genes for the alpha and beta subunits of E1 (acetoin:2,6-dichlorophenolindophenol oxidoreductase), E2 (dihydrolipoamide acetyltransferase), and E3 (dihydrolipoamide dehydrogenase) of the Pelobacter carbinolicus acetoin dehydrogenase enzyme system, which were designated acoA, acoB, acoC, and acoL, respectively.

Function

oxidoreductase activity, acting on the aldehyde or oxo group of donors, disulfide as acceptorGO:0016624
Substrates: acetoin oxidized lipoyl-AcoC
Products: acetaldehyde S-acetyldihydrolipoyl-AcoC

TPP-dependent cleavage releases acetaldehyde and reductively acetylates the lipoyl carrier. GO:0016624 names the assembled physiological redox class. Acetoin dehydrogenase (NAD+) GO:0019152 instead names acetoin/diacetyl interconversion and is not used. DCPIP assay activity is distinguished from native lipoyl chemistry.

PMID:1898934
Purified native Pelobacter E1, E2 and E3 reconstitute acetoin-dependent CoA-coupled NAD reduction.
The combination of purified Ao:DCPIP OR, DHLTA, and DHLDH in the presence of thiamine pyrophosphate and the substrate acetoin or methylacetoin resulted in a coenzyme A-dependent reduction of NAD.
PMID:8110297
N-terminal sequences link the purified Pelobacter components to the acoABCL genes.
Use of oligonucleotide probes, which were deduced from the N-terminal sequences of the purified enzyme components, identified the structural genes for the alpha and beta subunits of E1 (acetoin:2,6-dichlorophenolindophenol oxidoreductase), E2 (dihydrolipoamide acetyltransferase), and E3 (dihydrolipoamide dehydrogenase) of the Pelobacter carbinolicus acetoin dehydrogenase enzyme system, which were designated acoA, acoB, acoC, and acoL, respectively.
PMID:20508247
The review distinguishes acetoin cleavage from pyruvate decarboxylation and describes reductive acylation of E2-bound lipoamide.
This intermediate collapses, releasing acetaldehyde and leaving TPP with an activated hydroxyethyl group that is poised to acylate the lipoamide cofactor of the E2 subunit.
Part 3: E2 acetyl transfer to CoA
E2 acetyl transferReactionpc_e2_step

Annotons

Syntrophotalea carbinolica (historical Pelobacter carbinolicus) AcoC acetyl transfer
pc_e2
Participant: Gene Product: acoC (SYNCB)
Gene Product:
acoC (SYNCB)UniProtKB:Q59658
Family:
Lipoyl-bearing acetoin-system AcoC proteinsPANTHER:PTHR23151:SF90 Verified current subfamily classification. Its official name does not establish this protein's substrate; the exact protein and source-specific functional evidence constrain this role.
Representative Members: acoC (SYNCB)UniProtKB:Q59658

Function

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

Transfers lipoyl-bound acetyl to CoA. Pelobacter has purified component/reconstitution support. H16 and Pseudomonas carry a distinct alpha/beta-hydrolase architecture and their exact E2 chemistry remains a curated inference. Bacillus has canonical E2 motifs and native pathway evidence; no isolated Bacillus transfer assay is claimed.

PMID:8110297
N-terminal sequences link the purified Pelobacter components to the acoABCL genes.
Use of oligonucleotide probes, which were deduced from the N-terminal sequences of the purified enzyme components, identified the structural genes for the alpha and beta subunits of E1 (acetoin:2,6-dichlorophenolindophenol oxidoreductase), E2 (dihydrolipoamide acetyltransferase), and E3 (dihydrolipoamide dehydrogenase) of the Pelobacter carbinolicus acetoin dehydrogenase enzyme system, which were designated acoA, acoB, acoC, and acoL, respectively.
PMID:1898934
Purified native Pelobacter E1, E2 and E3 reconstitute acetoin-dependent CoA-coupled NAD reduction.
The combination of purified Ao:DCPIP OR, DHLTA, and DHLDH in the presence of thiamine pyrophosphate and the substrate acetoin or methylacetoin resulted in a coenzyme A-dependent reduction of NAD.
PMID:20508247
The review distinguishes acetoin cleavage from pyruvate decarboxylation and describes reductive acylation of E2-bound lipoamide.
This intermediate collapses, releasing acetaldehyde and leaving TPP with an activated hydroxyethyl group that is poised to acylate the lipoamide cofactor of the E2 subunit.
Part 4: E3 lipoyl redox regeneration
E3 lipoyl reoxidationReactionpc_e3_step

Annotons

Syntrophotalea carbinolica (historical Pelobacter carbinolicus) lipoyl redox regeneration
pc_e3
Participant: Gene Product: acoL (SYNCB)
Gene Product:
acoL (SYNCB)UniProtKB:Q60154
Family:
Acetoin-associated dihydrolipoyl dehydrogenasesPANTHER:PTHR22912:SF151 Verified current subfamily classification. Its official name does not establish this protein's substrate; the exact protein and source-specific functional evidence constrain this role.
Representative Members: acoL (SYNCB)UniProtKB:Q60154

Function

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

Regenerates the oxidized lipoyl carrier. AcoL is experimentally linked to Pelobacter and inferred from sequence/locus in Bacillus; the KT2440 and H16 native protein identities remain unassigned.

PMID:1898934
Purified native Pelobacter E3 uses NAD(H), supporting its redox regeneration role.
DHLDH had a native Mr of 110,000, consisted of two identical subunits of Mr 54,000, and reacted only with NAD(H) as a coenzyme.
PMID:8110297
N-terminal sequences link the purified Pelobacter components to the acoABCL genes.
Use of oligonucleotide probes, which were deduced from the N-terminal sequences of the purified enzyme components, identified the structural genes for the alpha and beta subunits of E1 (acetoin:2,6-dichlorophenolindophenol oxidoreductase), E2 (dihydrolipoamide acetyltransferase), and E3 (dihydrolipoamide dehydrogenase) of the Pelobacter carbinolicus acetoin dehydrogenase enzyme system, which were designated acoA, acoB, acoC, and acoL, respectively.
Bacillus subtilis 168 acetoin systemMetabolic Pathwaybs_native_system

Native strain 168 pathway genetics plus sequence-supported component chemistry. The paper reports small AcoC C-terminal differences from the later reference sequence.

Context
Bacillus subtilis subsp. subtilis str. 168NCBITaxon:224308
PMID:10368162
Native B. subtilis 168 acoA disruption impairs acetoin use; this establishes a locus requirement without separately reconstituting every subunit.
the mutant SA35 was unable to utilize acetoin as a carbon source, while the wild type started growing and kept doing so after the addition of acetoin.

Connections

bs_e1_step -> bs_e2_step Provides Input For
E1 supplies the acylated lipoyl intermediate to the E2 transfer reaction.
PMID:10368162
Bacillus AcoC contains lipoyl-domain and canonical catalytic-domain motifs supporting its E2 role by homology.
The N-terminal region of B. subtilis AcoC shares most characteristics with the dihydrolipoamide acyltransferases of various origins—such as Lys 43 , which is presumably lipoylated, and Gly 33 and Gly 54 , which flank this lysine residue—and with the corresponding C-terminal catalytic domains of various dihydrolipoamide acyltransferases, including the conserved putative active-site histidine-aspartate couple ( 3 , 16 , 22 ).
PMID:10368162
Native B. subtilis 168 acoA disruption impairs acetoin use; this establishes a locus requirement without separately reconstituting every subunit.
the mutant SA35 was unable to utilize acetoin as a carbon source, while the wild type started growing and kept doing so after the addition of acetoin.
PMID:20508247
The review distinguishes acetoin cleavage from pyruvate decarboxylation and describes reductive acylation of E2-bound lipoamide.
This intermediate collapses, releasing acetaldehyde and leaving TPP with an activated hydroxyethyl group that is poised to acylate the lipoamide cofactor of the E2 subunit.
bs_e2_step -> bs_e3_step Provides Input For
E2 leaves reduced lipoyl carrier for E3 oxidation.
PMID:10368162
Bacillus AcoL has the FAD, redox-cysteine and NAD-binding architecture expected for E3; this is sequence evidence.
AcoL exhibited the putative flavin adenine dinucleotide-binding domain ( 5 ) at the N-terminal region, an active disulfide bridge site at position Cys 38 and Cys 43 , a putative NAD(H)-binding region in the central part, and the putative interface region at the C terminus and therefore matched the characteristic properties of dihydrolipoamide dehydrogenases ( 16 , 22 ).
PMID:1898934
Purified native Pelobacter E1, E2 and E3 reconstitute acetoin-dependent CoA-coupled NAD reduction.
The combination of purified Ao:DCPIP OR, DHLTA, and DHLDH in the presence of thiamine pyrophosphate and the substrate acetoin or methylacetoin resulted in a coenzyme A-dependent reduction of NAD.
bs_e3_step -> bs_e1_step Provides Input For
Oxidized lipoyl carrier returns to E1; this is cofactor recycling, not a second carbon input.
PMID:10368162
Bacillus AcoL has the FAD, redox-cysteine and NAD-binding architecture expected for E3; this is sequence evidence.
AcoL exhibited the putative flavin adenine dinucleotide-binding domain ( 5 ) at the N-terminal region, an active disulfide bridge site at position Cys 38 and Cys 43 , a putative NAD(H)-binding region in the central part, and the putative interface region at the C terminus and therefore matched the characteristic properties of dihydrolipoamide dehydrogenases ( 16 , 22 ).
PMID:20508247
The review distinguishes acetoin cleavage from pyruvate decarboxylation and describes reductive acylation of E2-bound lipoamide.
This intermediate collapses, releasing acetaldehyde and leaving TPP with an activated hydroxyethyl group that is poised to acylate the lipoamide cofactor of the E2 subunit.
Part 2: E1 cleavage and reductive lipoyl acetylation
E1 acetoin cleavageReactionbs_e1_step

Annotons

Bacillus subtilis 168 acetoin-cleaving E1
bs_e1
Participant: Protein Complex: Bacillus subtilis 168 AcoA/AcoB E1 assembly
Protein Complex:
Bacillus subtilis 168 AcoA/AcoB E1 assembly Alpha/beta E1. Alpha2 beta2 is directly favored for H16 and is comparative architecture for other implementations; no cross-species subunit combination is asserted.
Active units:
E1 alpha component
Participant: Gene Product: acoA (BACSU)
Gene Product:
acoA (BACSU)UniProtKB:O31404
Family:
E1 alpha component familyPANTHER:PTHR11516 Verified broad classification. Its official name does not establish this protein's substrate; the exact protein and source-specific functional evidence constrain this role.
Representative Members: acoA (BACSU)UniProtKB:O31404
Role: Contributes to assembled E1 activity; neither isolated subunit is asserted sufficient.
PMID:10368162
Native B. subtilis 168 acoA disruption impairs acetoin use; this establishes a locus requirement without separately reconstituting every subunit.
the mutant SA35 was unable to utilize acetoin as a carbon source, while the wild type started growing and kept doing so after the addition of acetoin.
E1 beta component
Participant: Gene Product: acoB (BACSU)
Gene Product:
acoB (BACSU)UniProtKB:O34591
Family:
Acetoin-cleaving E1 beta (AcoB) subfamilyPANTHER:PTHR43257:SF3 Verified broad classification. Its official name does not establish this protein's substrate; the exact protein and source-specific functional evidence constrain this role.
Representative Members: acoB (BACSU)UniProtKB:O34591
Role: Contributes to assembled E1 activity; neither isolated subunit is asserted sufficient.
PMID:10368162
Native B. subtilis 168 acoA disruption impairs acetoin use; this establishes a locus requirement without separately reconstituting every subunit.
the mutant SA35 was unable to utilize acetoin as a carbon source, while the wild type started growing and kept doing so after the addition of acetoin.

Function

oxidoreductase activity, acting on the aldehyde or oxo group of donors, disulfide as acceptorGO:0016624
Substrates: acetoin oxidized lipoyl-AcoC
Products: acetaldehyde S-acetyldihydrolipoyl-AcoC

TPP-dependent cleavage releases acetaldehyde and reductively acetylates the lipoyl carrier. GO:0016624 names the assembled physiological redox class. Acetoin dehydrogenase (NAD+) GO:0019152 instead names acetoin/diacetyl interconversion and is not used. DCPIP assay activity is distinguished from native lipoyl chemistry.

PMID:10368162
Native B. subtilis 168 acoA disruption impairs acetoin use; this establishes a locus requirement without separately reconstituting every subunit.
the mutant SA35 was unable to utilize acetoin as a carbon source, while the wild type started growing and kept doing so after the addition of acetoin.
PMID:20508247
The review distinguishes acetoin cleavage from pyruvate decarboxylation and describes reductive acylation of E2-bound lipoamide.
This intermediate collapses, releasing acetaldehyde and leaving TPP with an activated hydroxyethyl group that is poised to acylate the lipoamide cofactor of the E2 subunit.
Part 3: E2 acetyl transfer to CoA
E2 acetyl transferReactionbs_e2_step

Annotons

Bacillus subtilis 168 AcoC acetyl transfer
bs_e2
Participant: Gene Product: acoC (BACSU)
Gene Product:
acoC (BACSU)UniProtKB:O31550
Family:
Canonical lipoyl E2 acyltransferases of 2-oxoacid dehydrogenase-type complexes B. subtilis AcoC has the canonical E2 architecture (lipoyl, peripheral subunit-binding and 2-oxoacid_dh catalytic domains). PANTHER's 19.0 classification file (PTHR23151:SF90) and UniProt (PTHR43178:SF5) disagree on its PANTHER family, so neither PANTHER id is asserted; both families are reviewed. It matches InterPro IPR050743 (2-oxoacid dehydrogenase family, E2 component), which does not by itself fix the acyl group; the acetoin assignment rests on the aco locus evidence.
Representative Members: acoC (BACSU)UniProtKB:O31550

Function

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

Transfers lipoyl-bound acetyl to CoA. Pelobacter has purified component/reconstitution support. H16 and Pseudomonas carry a distinct alpha/beta-hydrolase architecture and their exact E2 chemistry remains a curated inference. Bacillus has canonical E2 motifs and native pathway evidence; no isolated Bacillus transfer assay is claimed.

PMID:10368162
Bacillus AcoC contains lipoyl-domain and canonical catalytic-domain motifs supporting its E2 role by homology.
The N-terminal region of B. subtilis AcoC shares most characteristics with the dihydrolipoamide acyltransferases of various origins—such as Lys 43 , which is presumably lipoylated, and Gly 33 and Gly 54 , which flank this lysine residue—and with the corresponding C-terminal catalytic domains of various dihydrolipoamide acyltransferases, including the conserved putative active-site histidine-aspartate couple ( 3 , 16 , 22 ).
PMID:10368162
Native B. subtilis 168 acoA disruption impairs acetoin use; this establishes a locus requirement without separately reconstituting every subunit.
the mutant SA35 was unable to utilize acetoin as a carbon source, while the wild type started growing and kept doing so after the addition of acetoin.
PMID:20508247
The review distinguishes acetoin cleavage from pyruvate decarboxylation and describes reductive acylation of E2-bound lipoamide.
This intermediate collapses, releasing acetaldehyde and leaving TPP with an activated hydroxyethyl group that is poised to acylate the lipoamide cofactor of the E2 subunit.
Part 4: E3 lipoyl redox regeneration
E3 lipoyl reoxidationReactionbs_e3_step

Annotons

Bacillus subtilis 168 lipoyl redox regeneration
bs_e3
Participant: Gene Product: acoL (BACSU)
Gene Product:
acoL (BACSU)UniProtKB:O34324
Family:
Acetoin-associated dihydrolipoyl dehydrogenasesPANTHER:PTHR22912:SF219 Verified current subfamily classification. Its official name does not establish this protein's substrate; the exact protein and source-specific functional evidence constrain this role.
Representative Members: acoL (BACSU)UniProtKB:O34324

Function

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

Regenerates the oxidized lipoyl carrier. AcoL is experimentally linked to Pelobacter and inferred from sequence/locus in Bacillus; the KT2440 and H16 native protein identities remain unassigned.

PMID:10368162
Bacillus AcoL has the FAD, redox-cysteine and NAD-binding architecture expected for E3; this is sequence evidence.
AcoL exhibited the putative flavin adenine dinucleotide-binding domain ( 5 ) at the N-terminal region, an active disulfide bridge site at position Cys 38 and Cys 43 , a putative NAD(H)-binding region in the central part, and the putative interface region at the C terminus and therefore matched the characteristic properties of dihydrolipoamide dehydrogenases ( 16 , 22 ).