PP_2800 encodes a predicted class III pyridoxal-phosphate-dependent aminotransferase. Sequence-family assignments are consistent with a diaminobutyrate:2-oxoglutarate-type enzyme, but PP_2800 has not been characterized experimentally and its preferred physiological substrate and pathway remain unresolved. The canonical ectoine interpretation is not supported by the KT2440 pathway inventory, which lacks the downstream EctA, EctC, and EctD enzymes; PP_2800 instead lies in a GABA/diamine-metabolism neighborhood. It is distinct from the close PvdH ortholog PP_4223 that lies in the KT2440 pyoverdine biosynthetic locus.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0008483 transaminase activity | IEA GO_REF:0000002 | ACCEPT | Summary: A broad transaminase activity is supported by the class III aminotransferase fold, conserved family assignments, and the submitted UniProt product name. Reason: IPR004637, TIGR00709, and PANTHER PTHR43552:SF2 predict a diaminobutyrate-type transaminase, but no direct PP_2800 assay establishes its preferred in-vivo substrate. KT2440 lacks the downstream ectoine enzymes EctA/EctC/EctD, and PP_2800 lies in a GABA/diamine-metabolism neighborhood rather than the pyoverdine locus. Retain the experimentally safer broad activity until its physiological reaction is resolved. Supporting Evidence: file:PSEPK/PP_2800/PP_2800-uniprot.txt Belongs to the class-III pyridoxal-phosphate-dependent file:PSEPK/PP_2800/PP_2800-deep-research-openscientist.md No direct experimental data exist for PP_2800 file:PSEPK/PP_2800/PP_2800-deep-research-openscientist.md The ectoine pathway is therefore **genetically incomplete** |
| GO:0030170 pyridoxal phosphate binding | IEA GO_REF:0000002 | KEEP AS NON CORE | Summary: PLP binding is expected for this class III aminotransferase and is supported by the UniProt cofactor and family records. Reason: Cofactor binding supports the enzyme mechanism but is not the most informative statement of the protein's function. Supporting Evidence: file:PSEPK/PP_2800/PP_2800-uniprot.txt Name=pyridoxal 5'-phosphate |
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Download this section (compressed HTML)Q: What is the preferred physiological amino donor and acceptor of PP_2800, and what C4 amino-compound pathway recruits it in KT2440?
Experiment: Compare purified PP_2800 and PvdH kinetics across L-aspartate-4-semialdehyde, L-2,4-diaminobutyrate, GABA, glutamate, and 2-oxoglutarate, and pair the assay with targeted metabolomics of a clean PP_2800 deletion.
Hypothesis: PP_2800 is a C4 omega-amino-compound aminotransferase with substrate preferences distinct from the pyoverdine enzyme PvdH.
Type: comparative enzymology and metabolomics
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