PP_3157 encodes the predicted histidinol-phosphate phosphatase (HisN-like; EC 3.1.3.15) of Pseudomonas putida KT2440. It is predicted to hydrolyze L-histidinol phosphate to L-histidinol in the penultimate reaction of L-histidine biosynthesis. The protein belongs to the metal-dependent inositol-monophosphatase superfamily and is assigned to the histidine-specific His_9/TIGR02067 branch. Experimentally defined HisN sequence motifs and the family model distinguish this branch from related CysQ/SuhB-like IMPases, although PP_3157 itself has not been assayed. KT2440 also encodes the unrelated HAD-family candidate PP_5147, so their relative physiological contributions remain unresolved.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0000105 L-histidine biosynthetic process | IEA GO_REF:0000120 | UNDECIDED | Summary: PP_3157 is a credible but unverified candidate for the penultimate step. Reason: UniRule, UniPathway UPA00031, KEGG ppu00340, and the His_9 family assignment consistently place Q88I44 in L-histidine biosynthesis. The family-level literature supports this prediction, but there is no direct PP_3157 knockout, complementation result, or enzyme assay establishing its physiological role in KT2440. Supporting Evidence: file:PSEPK/PP_3157/PP_3157-deep-research-openscientist.md specific PP_3157 protein has not itself been enzymatically assayed |
| GO:0004401 histidinol-phosphatase activity | IEA GO_REF:0000120 | UNDECIDED | Summary: The substrate-specific activity is plausible but not established for PP_3157. Reason: GO:0004401 matches EC 3.1.3.15, RHEA:14465, the UniProt product name, UniRule UR001996117, and the histidine-specific IPR011809 family. These are concordant computational and family-level assignments, but no direct PP_3157 substrate-specific assay establishes GO:0004401 in KT2440. Supporting Evidence: file:PSEPK/PP_3157/PP_3157-deep-research-openscientist.md specific PP_3157 protein has not itself been enzymatically assayed |
| GO:0016791 phosphatase activity | IEA GO_REF:0000117 | MARK AS OVER ANNOTATED | Summary: This broad phosphatase term is redundant with GO:0004401. Reason: GO:0016791 adds no useful information beyond the specific histidinol-phosphatase activity already assigned. |
| GO:0042578 phosphoric ester hydrolase activity | IEA GO_REF:0000118 | MARK AS OVER ANNOTATED | Summary: This broad hydrolase term is redundant with GO:0004401. Reason: The TreeGrafter term is a generic ancestor of the specific histidinol-phosphatase activity and does not identify the biological substrate. |
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Download this section (compressed HTML)Q: Does PP_3157 carry substantial histidinol-phosphatase flux in KT2440, and how does its contribution overlap with the unrelated HAD enzyme PP_5147?
Experiment: Compare PP_3157 and PP_5147 single and double deletions during histidine limitation, then assay both purified enzymes against histidinol phosphate and representative alternative phosphomonoesters.
Type: genetics and substrate-specific enzyme assay
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