PA2580 is the Pseudomonas aeruginosa orthologue of MdaB, a soluble cytoplasmic flavoprotein of the flavodoxin-fold (DT-diaphorase-like) family of NAD(P)H:quinone oxidoreductases. The purified protein reduces quinones by a concerted two-electron transfer with very little semiquinone formation, which avoids the redox cycling that produces reactive oxygen species. Overexpressing it improves growth of a catalase (katA) mutant under H2O2 challenge but has no visible effect in wild type, so in P. aeruginosa it is at most a minor contributor to peroxide defence. Orthologues in Helicobacter species are NADPH-preferring quinone reductases needed for resistance to oxygen and peroxides.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0003824 catalytic activity | IEA GO_REF:0000117 | MODIFY | Summary: ARBA-derived root catalytic activity. Reason: Correct but uninformative; the specific activity, shown for the purified protein, is NAD(P)H dehydrogenase (quinone) activity, which the gene already carries (IBA, IMP). Proposed replacements: NAD(P)H dehydrogenase (quinone) activity Supporting Evidence: PMID:25085734 In in vitro assays, each enzyme was shown to reduce quinone substrates with only minimal semiquinone formation. |
| GO:0003955 NAD(P)H dehydrogenase (quinone) activity | IBA GO_REF:0000033 | ACCEPT | Summary: PAINT IBA from PTN002922793, seeded by E. coli MdaB and this protein (expected self-reference for a seed). Reason: Core activity, shown for the purified P. aeruginosa protein and for orthologues in the clade (H. pylori MdaB, an NAD(P)H quinone reductase). Propagation Review Root cause: NO FAILURE CORE Sources checked: UniProtKB:Q9I0Q6 · PA2580 SUPPORTS TRANSFER The target's own experimental annotation is a seed; expected, not circular. UniProtKB:P0AEY5 · E. coli MdaB SUPPORTS TRANSFER Second seed; FAD flavoprotein of the DT-diaphorase type (PMID:16630630). Supporting Evidence: PMID:25085734 In in vitro assays, each enzyme was shown to reduce quinone substrates with only minimal semiquinone formation. PMID:14977943 It was shown to be a flavoprotein that catalyzes two-electron transfer from NAD(P)H to quinones. |
| GO:0003955 NAD(P)H dehydrogenase (quinone) activity | IMP PMID:25085734 Pseudomonas aeruginosa MdaB and WrbA are water-soluble two-e... | ACCEPT | Summary: PseudoCAP row from Green et al. 2014: the purified P. aeruginosa MdaB orthologue reduces quinones by two-electron transfer. Reason: Core activity. The supporting data are in vitro assays with purified enzyme, so the claim is sound but the evidence code should be IDA, not IMP (the abstract reports no loss-of-function mutant; full text not read). One of two seeds of the PTN002922793 activity IBD. Supporting Evidence: PMID:25085734 In in vitro assays, each enzyme was shown to reduce quinone substrates with only minimal semiquinone formation. |
| GO:0005737 cytoplasm | IEA GO_REF:0000044 | MODIFY | Summary: UniProt subcellular-location mapping; the location line is ARBA-predicted. Reason: Correct but general. PA2580 is a water-soluble enzyme with no TM segment or signal peptide, so the specific location is cytosol, which the gene already carries (IBA). Proposed replacements: cytosol Supporting Evidence: PMID:25085734 Pseudomonas aeruginosa MdaB and WrbA are water-soluble two-electron quinone oxidoreductases |
| GO:0005829 cytosol | IBA GO_REF:0000033 | ACCEPT | Summary: PAINT IBA from PTN002922793, seeded by E. coli MdaB. Reason: Soluble flavoprotein with no membrane or export signals; consistent with its water-soluble behaviour in vitro. Propagation Review Root cause: NO FAILURE CORE Sources checked: UniProtKB:P0AEY5 · E. coli MdaB SUPPORTS TRANSFER Seed of the cytosol IBD. Supporting Evidence: PMID:25085734 Pseudomonas aeruginosa MdaB and WrbA are water-soluble two-electron quinone oxidoreductases |
| GO:0008753 NADPH dehydrogenase (quinone) activity | IEA GO_REF:0000003 | UNDECIDED | Summary: EC2GO mapping from EC 1.6.5.10, itself ARBA-assigned. Reason: NADPH preference is shown for H. pylori MdaB, but the P. aeruginosa paper is abstract-only and does not state the donor specificity of PA2580, and the EC number is an ARBA prediction. The broader NAD(P)H term is supported directly. Supporting Evidence: PMID:14977943 preferably uses NADPH as an electron donor |
| GO:0034599 cellular response to oxidative stress | IBA GO_REF:0000033 | KEEP AS NON CORE | Summary: PAINT IBA from PTN002922793, sole seed the PseudoCAP IMP on this protein (expected self-reference). Reason: Two-electron quinone reduction by MdaB is itself the protective step, so the term describes participation. The clade-level claim is better supported by knockout phenotypes of H. pylori MdaB (HP_0630, a leaf of this node) and H. hepaticus MdaB than by the PA seed. For P. aeruginosa the role is minor (protection seen only in a katA mutant), so non-core. Propagation Review Root cause: NO FAILURE NON CORE Sources checked: PANTHER:PTN002922793 · PTN002922793 SUPPORTS TRANSFER PAINT leaf GAF (cached 2026-10-28) lists 9 GO:0034599 leaves in 8 taxa, including H. pylori HP_0630, whose own knockout is oxidative-stress sensitive (PMID:14977943). UniProtKB:Q9I0Q6 · PA2580 SOURCE WEAK OR INFERRED Sole seed; overexpression protects only a katA mutant (PMID:25085734). Supporting Evidence: PMID:14977943 The mdaB mutant is also more sensitive to H(2)O(2), organic hydroperoxides, and the superoxide-generating agent paraquat. PMID:17923370 The mdaB mutant was also more sensitive to oxidative stress reagents such as H(2)O(2), cumene hydroperoxide, t-butyl hydroperoxide, and paraquat. |
| GO:0034599 cellular response to oxidative stress | IMP PMID:25085734 Pseudomonas aeruginosa MdaB and WrbA are water-soluble two-e... | KEEP AS NON CORE | Summary: PseudoCAP IMP from Green et al. 2014: overexpressed PA2580 improves growth of a katA mutant under H2O2 challenge; no effect in wild type. Reason: Gain-of-function evidence (GO counts overexpression as IMP) in a catalase-null background only; the authors describe a potential rather than demonstrated role. The enzyme does the protective chemistry itself, so the claim is plausible, but in P. aeruginosa it is secondary to catalase. Supporting Evidence: PMID:25085734 in a katA mutant, H2O2 challenged strains over-expressing the WrbA and MdaB orthologs grew significantly better than the empty plasmid control. PMID:25085734 However, when each was individually over-expressed in P. aeruginosa no overt H2O2-protective phenotype was observed. |
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Experiment: Delete PA2580 alone and in combination with katA and wrbA, and measure H2O2, paraquat and quinone (menadione, phenazine) sensitivity, alongside steady-state kinetics of the purified enzyme with NADH versus NADPH.
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