PP_2482 encodes a MoaA-family radical-SAM protein with the conserved CxxxCxxC iron-sulfur-binding motif. It is related to, but substantially diverged from, canonical KT2440 MoaA and lies next to an unresolved MobA-like NTP-transferase-domain protein; its physiological substrate and equivalence to the canonical GTP-cyclizing MoaA enzyme remain unresolved.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0003824 catalytic activity | IEA GO_REF:0000002 | UNDECIDED | Summary: Catalytic activity is plausible for this radical-SAM family member, but the exact reaction is unresolved. Reason: Sequence features establish family membership but do not prove use of GTP as the physiological substrate. Supporting Evidence: file:PSEPK/moaA/moaA-bioinformatics/RESULTS.md - All three KT2440 proteins have comparable lengths (322-337 aa), the canonical radical-SAM `CxxxCxxC` pattern near the N terminus, and two detected `CxxC` patterns. These features support radical-SAM/MoaA-like family membership but do not establish the same physiological substrate or pathway contribution. file:PSEPK/PP_2482/PP_2482-deep-research-openscientist.md 1. **No direct experimental study of the *P. putida* ortholog.** All functional claims for PP_2482 specifically are made by inference. |
| GO:0006777 Mo-molybdopterin cofactor biosynthetic process | IEA GO_REF:0000120 | UNDECIDED | Summary: Molybdenum-cofactor pathway involvement is plausible from family and locus context but lacks gene-specific evidence. Reason: PP_2482 may support a local molybdoenzyme-associated system, but redundancy with or independence from canonical moaA has not been demonstrated. Supporting Evidence: file:PSEPK/moaA/moaA-bioinformatics/RESULTS.md The sequence analysis therefore supports keeping PP_2482 and PP_1969 as MoaA-family candidates while reserving the unqualified GTP 3',8'-cyclase role for Q88E69 unless gene-specific biochemical, genetic, or stronger phylogenetic evidence resolves the paralogs. file:PSEPK/PP_2482/PP_2482-deep-research-openscientist.md 1. **No direct experimental study of the *P. putida* ortholog.** All functional claims for PP_2482 specifically are made by inference. |
| GO:0046872 metal ion binding | IEA GO_REF:0000104 | KEEP AS NON CORE | Summary: Metal-ion binding is consistent with the radical-SAM iron-sulfur motif but is non-core. Reason: The sequence and UniProt record support an iron-sulfur-binding radical-SAM fold. |
| GO:0051536 iron-sulfur cluster binding | IEA GO_REF:0000002 | MARK AS OVER ANNOTATED | Summary: This broad iron-sulfur-cluster binding term is redundant with the more specific retained [4Fe-4S]-cluster binding annotation. Reason: UniProt records a [4Fe-4S] cofactor for Q88K11, so GO:0051539 captures the supported cofactor binding more precisely. |
| GO:0051539 4 iron, 4 sulfur cluster binding | IEA GO_REF:0000120 | KEEP AS NON CORE | Summary: Specific [4Fe-4S]-cluster binding is plausible but is not an exact pathway-function assignment. Reason: UniProt and the conserved cysteine motif support a radical-SAM [4Fe-4S] cluster. |
| GO:0061798 GTP 3',8'-cyclase activity | IEA GO_REF:0000118 | UNDECIDED | Summary: Exact GTP 3',8'-cyclase activity cannot be established for this divergent paralog. Reason: Q88K11 lacks the MoaA-specific InterPro records present on reviewed Q88E69 and is only 36.25% identical to it; no direct assay resolves substrate specificity. Supporting Evidence: file:PSEPK/moaA/moaA-bioinformatics/RESULTS.md - Q88E69 is 36.25% identical to Q88K11 (PP_2482) and 37.85% identical to Q88LG4 (PP_1969) over aligned residue pairs. Q88K11 and Q88LG4 are 66.15% identical to one another. This pattern supports a closer relationship between the two unreviewed candidates than either has to canonical moaA, and does not support assuming that all three are interchangeable copies. file:PSEPK/PP_2482/PP_2482-deep-research-openscientist.md 1. **No direct experimental study of the *P. putida* ortholog.** All functional claims for PP_2482 specifically are made by inference. |
| GO:0061799 cyclic pyranopterin monophosphate synthase activity | IEA GO_REF:0000118 | REMOVE | Summary: cPMP synthase is the distinct MoaC reaction and should not be assigned to a stand-alone MoaA-family protein. Reason: Even canonical bacterial MoaA forms the cyclic GTP intermediate; MoaC converts that intermediate to cPMP. Supporting Evidence: file:PSEPK/moaA/moaA-uniprot.txt DE RecName: Full=GTP 3',8-cyclase {ECO:0000255|HAMAP-Rule:MF_01225}; file:PSEPK/moaC/moaC-uniprot.txt DE RecName: Full=Cyclic pyranopterin monophosphate synthase {ECO:0000255|HAMAP-Rule:MF_01224}; |
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Download this section (compressed HTML)Q: Does PP_2482 cyclize GTP, act on another purine-derived substrate, or serve a specialized role in the adjacent molybdoenzyme-associated system?
Experiment: Compare purified PP_2482 with canonical MoaA for GTP turnover and cyclic intermediate formation, and test complementation of a moaA deletion.
Type: comparative enzyme assay and genetic complementation
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