PP_3198 encodes a compact Rieske [2Fe-2S]-binding ferredoxin-domain protein in the KT2440 flavonoid-degradation locus. KEGG assigns it to FdeD orthology group K26179 and the predicted naringenin hydroxylation step R13074. Its cofactor-binding role is well supported, but its electron donor, electron acceptor, and requirement for the proposed reaction remain untested.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0051537 2 iron, 2 sulfur cluster binding | IEA GO_REF:0000002 | ACCEPT | Summary: The Rieske domain and conserved ligand-rich region support [2Fe-2S] cluster binding. Reason: UniProt, InterPro, Pfam, and sequence conservation independently identify a Rieske [2Fe-2S] domain. Supporting Evidence: file:PSEPK/PP_3198/PP_3198-uniprot.txt InterPro; IPR017941; Rieske_2Fe-2S. file:PSEPK/PP_3198/PP_3198-bioinformatics/RESULTS.md Both proteins are compact Rieske [2Fe-2S]-domain proteins. |
| GO:0046275 flavonoid catabolic process | ISS file:PSEPK/PP_3198/PP_3198-bioinformatics/RESULTS.md | REMOVE | Summary: Withdraw the inherited pathway-participation proposal; no FdeD-catalyzed or cofactor-dependent step has been established. Reason: The locus, K26179 assignment and Rieske architecture identify a candidate, but neither PP_3198 nor Hsero_1006 has an established physiological electron donor, acceptor or flavonoid-catabolic step. Purified FdeE works without added FdeD; that does not exclude another role, but it supplies no positive evidence of participation by FdeD. The same-role comparators Hsero_1006 and bll6426 likewise decline a process assertion. Retain this inherited row for provenance while withdrawing the proposal; cluster binding remains supported and native pathway involvement remains a knowledge gap. No assertion of biological absence is made. The retired flag records deliberate withdrawal of this curator-authored proposal from the active set; it does not report disappearance of an upstream GOA annotation. REMOVE records withdrawal of this earlier curator-authored NEW proposal, not removal of a current GOA assertion. It does not claim that the protein is biologically incapable of participating in flavonoid catabolism. Supporting Evidence: file:PSEPK/PP_3198/PP_3198-bioinformatics/RESULTS.md KEGG target mapping: `ppu:PP_3198 -> ko:K26179` file:PSEPK/PP_3198/PP_3198-bioinformatics/RESULTS.md Pairwise identity over aligned residue pairs: 45.6% |
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Download this section (compressed HTML)Q: Does PP_3198 transfer electrons to PP_3199 during naringenin hydroxylation in KT2440?
Experiment: Reconstitute PP_3198, PP_3199, candidate cellular reductases, FAD, and naringenin; monitor electron transfer and hydroxylated product formation.
Type: biochemical reconstitution
What is not known — curated, literature-grounded statements of the open unknowns (the inverse of core functions).
Gap: The electron donor and physiological electron acceptor of PP_3198 are unknown.
OPEN BIOLOGYCURATION
What is known: K26179 placement associates PP_3198 with R13074, but available evidence does not establish direct electron transfer to PP_3199/FdeE or another enzyme.
Significance: Partner identity is needed before assigning a specific oxidoreductase activity or complex.
What would resolve it: Reconstitute PP_3198 with candidate reductases and FdeE-family proteins while monitoring electron transfer and product formation.
Provenance (the field's own admissions):
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