PA2280 encodes ArsH, an FMN-binding flavodoxin-like NADPH-dependent reductase of the ArsH family, encoded in the arsenic-resistance (ars) gene cluster of Pseudomonas aeruginosa. Recombinant P. aeruginosa ArsH reduces quinones (NAD(P)H quinone oxidoreductase activity) and azo dyes, with NADPH as the preferred electron donor; ArsH proteins from other bacteria are likewise NADPH-dependent quinone reductases. Its physiological substrate and its contribution to arsenic resistance in P. aeruginosa have not been established.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0016491 oxidoreductase activity | IEA GO_REF:0000002 | MODIFY | Summary: InterPro2GO from the FMN reductase-like domain (IPR005025). Reason: Correct but general; recombinant P. aeruginosa ArsH has NAD(P)H quinone oxidoreductase activity, so GO:0003955 is supported. Proposed replacements: NAD(P)H dehydrogenase (quinone) activity Supporting Evidence: PMID:26621870 The ArsH, MdaB and YieF family members all show azoreductase and NQO activities. |
| GO:0016655 oxidoreductase activity, acting on NAD(P)H, quinone or similar compound as acceptor | IBA GO_REF:0000033 | MODIFY | Summary: PAINT IBA from PTN008682975, whose sole seed is this gene's PseudoCAP IDA citing a paper on Synechocystis ArsH (PMID:22304305). The target appearing in its own WITH/FROM is expected. Reason: The activity is correct for PA2280, but on independent grounds (PMID:26621870, recombinant P. aeruginosa ArsH), not the seed's citation. For PA2280 the specific GO:0003955 NAD(P)H dehydrogenase (quinone) activity is supported. The node term is a reasonable, family-level choice for a clade of bacterial, algal and fungal ArsH proteins, most without experimental data. Propagation Review Root cause: SOURCE WEAK OR INFERRED Failure modes: SOURCE MISCITATION Sources checked: PANTHER:PTN008682975 · PTN008682975 SUPPORTS TRANSFER QuickGO (2026-10-28) lists 9 GO:0016655 IBA leaves (PA2280, Gloeobacter glr0005, two Klebsormidium and five fungal ArsH-like proteins). The term fits characterised ArsH proteins. UniProtKB:Q9I1J5 · PA2280 SOURCE BAD The seed cites a Synechocystis paper as IDA for PA2280; the claim is true by PMID:26621870, which should be the cited evidence. Proposed replacements: NAD(P)H dehydrogenase (quinone) activity Supporting Evidence: PMID:26621870 The ArsH, MdaB and YieF family members all show azoreductase and NQO activities. |
| GO:0052873 FMN reductase (NADPH) activity | IEA GO_REF:0000117 | UNDECIDED | Summary: ARBA machine-learning IEA, matching the ARBA-derived RecName "NADPH-dependent FMN reductase ArsH". Reason: FMN is the bound cofactor of ArsH and NADPH the preferred reductant, but reduction of free FMN as a substrate (the meaning of the GO term) has not been shown for PA2280 in the material available; the characterised activity is quinone and azo reduction. The ARBA name and rule are unvetted predictions. Supporting Evidence: PMID:26621870 The ArsH, MdaB and YieF family members all show azoreductase and NQO activities. |
| GO:0016655 oxidoreductase activity, acting on NAD(P)H, quinone or similar compound as acceptor | IDA PMID:22304305 ArsH from the cyanobacterium Synechocystis sp. PCC 6803 is a... | MODIFY | Summary: PseudoCAP IDA citing Hervas et al. 2012, a biochemical study of Synechocystis sp. PCC 6803 ArsH. Sole seed of the GO:0016655 IBD at PTN008682975. Reason: The cached abstract states that the protein expressed, purified and assayed was Synechocystis ArsH, so on the abstract the paper is not direct evidence for PA2280 (full text not read); at most it supports an ISS transfer. The activity is nonetheless correct for PA2280, shown directly with recombinant P. aeruginosa ArsH in PMID:26621870, which supports the more specific GO:0003955 NAD(P)H dehydrogenase (quinone) activity. Proposed replacements: NAD(P)H dehydrogenase (quinone) activity Supporting Evidence: PMID:26621870 we therefore characterized recombinant enzymes following expression of a group of putative azoreductase genes from P. aeruginosa expressed in Escherichia coli PMID:26621870 The ArsH, MdaB and YieF family members all show azoreductase and NQO activities. |
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Download this section (compressed HTML)Q: What is the physiological substrate of P. aeruginosa ArsH, and does it contribute to arsenic or organoarsenical resistance, given its position in the ars cluster?
Experiment: Compare arsenite, methylarsenite and arsenate tolerance and quinone-stress sensitivity of a PA2280 deletion with wild type, and assay purified ArsH with trivalent organoarsenicals.
Type: genetic and biochemical
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