ArgD (PP_4481) is a pyridoxal-phosphate-dependent acyl-ornithine aminotransferase embedded in the KT2440 arginine succinyltransferase catabolic operon. Its primary predicted physiological function is N2-succinyl-L-ornithine transamination (EC 2.6.1.81) in arginine catabolism. Secondary acetylornithine and succinyldiaminopimelate activities remain plausible because this enzyme family is substrate-promiscuous.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0003992 N2-acetyl-L-ornithine:2-oxoglutarate 5-transaminase activity | IEA GO_REF:0000120 | KEEP AS NON CORE | Summary: P59319 is likely capable of acetylornithine transamination, but this is not its primary pathway role. Reason: Reviewed UniProt assigns EC 2.6.1.11, but PP_4481 lies in the AST catabolic operon and PANTHER places it in AstC-like SF113. Related AstC enzymes can retain ACOAT activity through substrate promiscuity. Supporting Evidence: file:PSEPK/argD/argD-uniprot.txt Full=Acetylornithine aminotransferase |
| GO:0005737 cytoplasm | IEA GO_REF:0000120 | KEEP AS NON CORE | Summary: PP_4481 is a soluble cytoplasmic acyl-ornithine aminotransferase. Reason: The location is supported but is secondary to the reaction. |
| GO:0006520 amino acid metabolic process | IEA GO_REF:0000002 | MARK AS OVER ANNOTATED | Summary: This root-level process term is redundant with the specific arginine-catabolism assignment. Reason: GO:0006527 captures the relevant pathway role more precisely. |
| GO:0006525 arginine metabolic process | IEA GO_REF:0000002 | KEEP AS NON CORE | Summary: This broad term correctly encompasses the primary arginine-catabolic role. Reason: GO:0006527 captures the catabolic process more precisely in the synthesized core function. |
| GO:0006526 L-arginine biosynthetic process | IEA GO_REF:0000120 | KEEP AS NON CORE | Summary: PP_4481 is a plausible promiscuous contributor to arginine biosynthesis, although its primary physiological role is in AST-pathway catabolism. Reason: Prior module-level research identifies PP_4481 and PP_0372 as alternative, promiscuous class-III transaminases that can fill biosynthetic step 4. The AST-operon context and AstC-like subfamily still make catabolism the core role, but the biosynthetic contribution should be retained rather than discarded. Supporting Evidence: file:projects/P_PUTIDA/deep-research/PSEPK__arginine_biosynthesis__ppu00220-deep-research-openscientist.md This is a genuine lineage-specific alternative, not an over-annotation to discard |
| GO:0008483 transaminase activity | IEA GO_REF:0000120 | MARK AS OVER ANNOTATED | Summary: This generic transaminase term is redundant with the substrate-specific AstC activity. Reason: GO:0043825 captures the biologically relevant reaction. |
| GO:0030170 pyridoxal phosphate binding | IEA GO_REF:0000120 | KEEP AS NON CORE | Summary: Pyridoxal 5'-phosphate is the required ArgD cofactor. Reason: Correct supporting chemistry, but the specific transaminase activity is more informative. |
| GO:0042802 identical protein binding | IEA GO_REF:0000118 | MARK AS OVER ANNOTATED | Summary: ArgD is predicted to be homodimeric, but generic self-binding is not a useful functional annotation. Reason: The TreeGrafter term does not identify a distinct binding role beyond oligomerization of the enzyme. |
| GO:0043825 succinylornithine:2-oxoglutarate transaminase activity | ISS file:PSEPK/argD/argD-deep-research-openscientist.md | NEW | Summary: PP_4481 should be annotated to the AstC/AruC succinylornithine-transaminase activity. Reason: The protein is embedded in the AST operon, belongs to the AstC-like PANTHER SF113 branch, and is a close ortholog of characterized Pseudomonas aeruginosa AruC. This is an orthology/context inference, not a direct KT2440 enzyme assay. Supporting Evidence: file:PSEPK/argD/argD-deep-research-openscientist.md the **primary physiological role of PP_4481 is catabolic**: it is the **Nยฒ-succinyl-L-ornithine 5-aminotransferase (AstC/AruC, EC 2.6.1.81)** file:interpro/panther/PTHR11986/PTHR11986-entries.csv P59319,Acetylornithine aminotransferase,protein,160488,Pseudomonas putida (strain ATCC 47054 / DSM 6125 / CFBP 8728 / NCIMB 11950 / KT2440),Pseudomonas putida (strain ATCC 47054 / DSM 6125 / CFBP 8728 / NCIMB 11950 / KT2440),argD,406,PTHR11986:SF113,SUCCINYLORNITHINE TRANSAMINASE,True PMID:23484010 AstC is a dimeric, pyridoxal phosphate (PLP)-dependent ฮดโaminotransferase that operates a ping-pong bi-bi reaction mechanism with succinylornithine (SO) and ฮฑ-ketoglutarate (ฮฑKG) as co-substrates and succinylglutamic semialdehyde and glutamate as co-products |
| GO:0006527 L-arginine catabolic process | ISS file:PSEPK/argD/argD-deep-research-openscientist.md | NEW | Summary: PP_4481 is a component of the arginine succinyltransferase catabolic pathway. Reason: The AST-operon context establishes the physiological direction and distinguishes this role from the electronically propagated biosynthetic process annotation. Supporting Evidence: file:PSEPK/argD/argD-deep-research-openscientist.md the **primary physiological role of PP_4481 is catabolic**: it is the **Nยฒ-succinyl-L-ornithine 5-aminotransferase (AstC/AruC, EC 2.6.1.81)** file:interpro/panther/PTHR11986/PTHR11986-entries.csv P59319,Acetylornithine aminotransferase,protein,160488,Pseudomonas putida (strain ATCC 47054 / DSM 6125 / CFBP 8728 / NCIMB 11950 / KT2440),Pseudomonas putida (strain ATCC 47054 / DSM 6125 / CFBP 8728 / NCIMB 11950 / KT2440),argD,406,PTHR11986:SF113,SUCCINYLORNITHINE TRANSAMINASE,True PMID:9393691 The aruR, aruC, aruD, aruB, and aruE genes specify the ArgR regulatory protein, N2-succinylornithine 5-aminotransferase, N-succinylglutamate 5-semialdehyde dehydrogenase, N2-succinylarginine dihydrolase, and N-succinylglutamate desuccinylase, respectively |
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