aruG (PA0897) encodes the beta chain of the arginine and ornithine N2-succinyltransferase of Pseudomonas aeruginosa PAO1 (EC 2.3.1.109), an acyl-CoA N-acyltransferase-fold protein of the AstA family. Together with its paralogous partner AruF (P80357) it forms a heterotetramer with two chains of each type that transfers succinyl from succinyl-CoA to L-arginine or L-ornithine, the first reaction of the arginine succinyltransferase (AST) pathway, the main route of aerobic arginine and ornithine utilization. The enzyme follows Michaelis-Menten kinetics with arginine but is allosteric with ornithine and is inhibited by spermidine. The gene lies in the ArgR-controlled aruCFGDB operon.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0006527 L-arginine catabolic process | IBA GO_REF:0000033 | ACCEPT | Summary: PAINT IBA from PTN000764516; AruG (P80358) is itself one of the four seeds. Reason: All characterized members below the node work in the AST pathway; for this chain the role is direct, as a subunit of the enzyme that initiates it. Supporting Evidence: PMID:9393691 The arginine succinyltransferase (AST) pathway is the major arginine and ornithine utilization (aru) pathway under aerobic conditions in Pseudomonas aeruginosa. PMID:9393691 the aruF and aruG genes encode the subunits (AruAI and AruAII) of arginine and ornithine N2-succinyltransferases. |
| GO:0006527 L-arginine catabolic process | IDA PMID:16593724 N-Succinylated intermediates in an arginine catabolic pathwa... | ACCEPT | Summary: PseudoCAP row from Jann et al. 1986, which established the succinylarginine pathway in P. aeruginosa with aru mutants and crude-extract enzyme assays. Reason: The process claim is correct for this chain. The paper predates the cloning of the aru genes, so assignment of the transferase step to this gene rests on the later genetics (PMID:9393691); the curator attribution is consistent with it. Supporting Evidence: PMID:16593724 Enzyme assays with crude P. aeruginosa extracts established the following pathway: L-arginine + succinyl-CoA --> N(2)-succinylarginine PMID:9393691 the aruF and aruG genes encode the subunits (AruAI and AruAII) of arginine and ornithine N2-succinyltransferases. |
| GO:0006527 L-arginine catabolic process | IEA GO_REF:0000002 | ACCEPT | Summary: InterPro2GO from IPR007041 (AstA/AruG succinyltransferase). Reason: Correct; the AstA family is specific to the AST arginine-catabolic pathway. Supporting Evidence: PMID:9393691 The arginine succinyltransferase (AST) pathway is the major arginine and ornithine utilization (aru) pathway under aerobic conditions in Pseudomonas aeruginosa. |
| GO:0008791 L-arginine N-succinyltransferase activity | IEA GO_REF:0000120 | ACCEPT | Summary: L-arginine N-succinyltransferase activity is correct for the enzyme this chain belongs to; only the enables qualifier overstates single-chain autonomy. Reason: The purified Pseudomonas enzyme is a heterotetramer of two different chains, so the activity belongs to the complex. The term is correct, and contributes_to correctly scopes the claim to the complex; the qualifier error is recorded as a WRONG_QUALIFIER source defect (same idiom as the E. coli NuoB/NuoC and CysI reviews). The core function uses contributes_to. Supporting Evidence: PMID:7523119 After SDS/PAGE two subunits of 35 kDa and 37 kDa were evident, indicating that the enzyme is a heterotetramer. PMID:9393691 the aruF and aruG genes encode the subunits (AruAI and AruAII) of arginine and ornithine N2-succinyltransferases. file:PSEAE/aruG/aruG-uniprot.txt SUBUNIT: Heterotetramer of two alpha and two beta subunits. |
| GO:0009015 N-succinylarginine dihydrolase activity | IBA GO_REF:0000033 | REMOVE | Summary: PAINT IBA of N-succinylarginine dihydrolase activity, seeded only by E. coli AstB, propagated to the transferase chain because PTN000764516 spans both PTHR30420 subfamilies. Reason: This protein is the beta chain of arginine/ornithine N-succinyltransferase (Pfam AstA, an acyl-CoA N-acyltransferase), not a dihydrolase. P. aeruginosa encodes the dihydrolase separately as aruB in the same operon. The IBD sits too deep for this term. Propagation Review Root cause: PROPAGATION BAD Failure modes: ROLE CONFLATION Sources checked: PANTHER:PTN000764516 SUPPORTS SOURCE BUT NOT TARGET Node covers both the AstA transferase (SF1, 53 members) and AstB dihydrolase (SF2, 138 members) subfamilies; the dihydrolase IBD belongs on the SF2 clade. GO:0006527 at this node is fine; only GO:0009015 is misplaced. UniProtKB:P76216 SUPPORTS SOURCE BUT NOT TARGET E. coli AstB is a genuine dihydrolase of a different fold. Supporting Evidence: PMID:9393691 the aruF and aruG genes encode the subunits (AruAI and AruAII) of arginine and ornithine N2-succinyltransferases. file:PSEAE/aruG/aruG-uniprot.txt Pfam; PF04958; AstA; 1. 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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Download this section (compressed HTML)Q: Does the beta chain contribute catalytic residues, the allosteric ornithine site, or assembly contacts to the AruF/AruG heterotetramer?
Suggested experts: bacterial arginine catabolism
Experiment: Express AruF and AruG separately and together, and compare succinyltransferase activity and ornithine cooperativity of each chain and of the reconstituted heterotetramer.
Type: complex reconstitution and enzyme assay
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