Bacterial DsbA/DsbB oxidative protein folding

A reusable bacterial envelope module for introduction of disulfide bonds into exported proteins. Membrane DsbB transfers electrons from reduced DsbA into the respiratory quinone pool, regenerating oxidized DsbA. Periplasmic DsbA uses that oxidizing equivalent to oxidize cysteine pairs in newly exported substrate proteins and becomes reduced again. The module ends at substrate disulfide formation; DsbC/DsbD-mediated isomerization and repair of incorrect disulfides are a separate pathway. Pseudomonas putida KT2440 supplies one DsbA and two closely related DsbB paralogs as exact exemplars.

MODULE:bacterial_dsbab_oxidative_foldingDRAFTCONCRETEBiological Processmodules/bacterial_dsbab_oxidative_folding.yaml
protein foldingGO:0006457
GO:0006457
protein folding
GO:0006457 provides the broad process context for Dsb-dependent oxidative folding.
GO:0015035
protein-disulfide reductase activity
The official GO definition is "Catalysis of the reaction: a protein with reduced sulfide groups = a protein with oxidized disulfide bonds." The reversible equality makes this a compatible non-directional oxidoreductase term, not the primary direction-specific DsbB function.
GO:0009055
electron transfer activity
GO:0009055 captures the direction-neutral electron relay by which DsbB transfers reducing equivalents from DsbA toward respiratory quinone.
GO:0015036
disulfide oxidoreductase activity
GO:0015036 captures DsbA-catalyzed oxidation of substrate sulfide groups to disulfides.
file:PSEPK/dsbA/dsbA-uniprot.txt
UniProtKB entry for PSEPK DsbA
Q88RK2 is a periplasmic DsbA-family disulfide oxidoreductase.
file:PSEPK/dsbB1/dsbB1-uniprot.txt
UniProtKB entry for PSEPK DsbB1
P59345 is a membrane DsbB protein required for periplasmic disulfide formation.
file:PSEPK/dsbB2/dsbB2-uniprot.txt
UniProtKB entry for PSEPK DsbB2
P59344 is a second membrane DsbB protein required for periplasmic disulfide formation.
PMID:9342327
Respiratory chain is required to maintain oxidized states of the DsbA-DsbB disulfide bond formation system in aerobically growing Escherichia coli cells.
Primary in vivo experiments connect DsbB-dependent DsbA reoxidation to quinones and the respiratory electron-transfer chain.
These results suggest that the respiratory electron transfer chain participates in the oxidation of DsbA, by acting primarily on DsbB.
PMID:12853466
Mechanism of the electron transfer catalyst DsbB from Escherichia coli.
Purified-system experiments establish direct DsbB-catalyzed oxidation of DsbA by ubiquinone.
The membrane protein DsbB from Escherichia coli is essential for disulfide bond formation and catalyses the oxidation of the periplasmic dithiol oxidase DsbA by ubiquinone.

GO:0015035 is retained in the gene reviews as a non-core, reversible protein-disulfide oxidoreductase annotation; its official definition does not establish a reductive or oxidative physiological direction. The module uses GO:0009055 for DsbB's core quinone-linked electron-transfer role. DsbA's own redox states are omitted from its substrate/product list because DsbA is the annoton participant; its oxidation state is instead represented by the reciprocal connections and part descriptions. KT2440 encodes two DsbB paralogs with the same family and GO assignments, but whether they are condition-specific or substrate-partitioned remains open.

3Nodes
2Parts
0Variant Sets
0Variants
2Annotons
2Connections

Derived QC

Recommended-field compliance

100.0% recommended fields populated

All recommended fields populated.

Module deep research

✗ none found

No MODULE:bacterial_dsbab_oxidative_folding 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 (3/3 grounded genes reviewed)

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

Gene Review Complete Deep research
dsbA Q88RK2 ✓ ✓ ✗
dsbB1 P59345 ✓ ✓ ✗
dsbB2 P59344 ✓ ✓ ✗

Details

Context
bacteriaNCBITaxon:2
Bacterial DsbA/DsbB oxidative protein foldingBiological Processbacterial_dsbab_oxidative_folding
protein foldingGO:0006457
Context
bacteriaNCBITaxon:2

Connections

Part: quinone-coupled regeneration of oxidized DsbA
DsbB-dependent DsbA reoxidationReactiondsbb_dsbA_reoxidation

Plasma-membrane DsbB accepts reducing equivalents from DsbA and transfers them toward the quinone pool, regenerating the oxidized DsbA active site.

Annotons

DsbB membrane oxidoreductase
dsbb_oxidative_folding_component
Participant: Family: bacterial DsbB family
Family:
bacterial DsbB familyPANTHER:PTHR36570:SF3
Representative Members: PSEPK DsbB1 exemplarUniProtKB:P59345 PSEPK DsbB2 exemplarUniProtKB:P59344

Function

electron transfer activityGO:0009055
Substrates: reduced DsbA respiratory quinone
Products: oxidized DsbA quinol

Processes

protein foldingGO:0006457

Locations

plasma membraneGO:0005886

Reoxidizes reduced DsbA through a quinone-linked membrane relay.

Part: disulfide introduction into exported substrate proteins
DsbA-catalyzed substrate oxidationReactiondsba_substrate_oxidation

Oxidized periplasmic DsbA introduces disulfide bonds into cysteine pairs of newly exported proteins and becomes reduced in the process.

Annotons

DsbA disulfide oxidoreductase
dsba_disulfide_oxidoreductase
Participant: Family: bacterial DsbA family
Family:
bacterial DsbA familyPANTHER:PTHR35891:SF2
Representative Members: PSEPK DsbA exemplarUniProtKB:Q88RK2

Function

disulfide oxidoreductase activityGO:0015036
Substrates: exported protein with reduced cysteine residues
Products: exported protein with a disulfide bond

Processes

protein foldingGO:0006457

Locations

periplasmic spaceGO:0042597

Introduces disulfide bonds into exported proteins.