astA-I

UniProt ID: Q88EI3
Organism: Pseudomonas putida KT2440
Review Status: COMPLETE
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Gene Description

AstA-I (PP_4479) is the beta-like component of the split arginine/ornithine N-succinyltransferase found in Pseudomonas putida KT2440. Together with the adjacent alpha-like AstA-II chain, it is predicted to form the first enzyme of the arginine succinyltransferase pathway, transferring succinyl-CoA to L-arginine and also accepting L-ornithine. The reaction commits these amino acids to aerobic catabolism through N-succinylated intermediates.

Existing Annotations Review

GO Term Evidence Action Reason
GO:0006527 L-arginine catabolic process
IEA
GO_REF:0000002 		ACCEPT
Summary: AstA-I contributes to the initiating succinylation reaction of the AST arginine-catabolic pathway.
Reason: The exact KT2440 protein is assigned to the AstA/AruG family and lies next to the complementary AstA-II chain. Pseudomonas aeruginosa genetics and biochemistry establish the homologous two-chain transferase as the entry reaction for aerobic arginine utilization.
Supporting Evidence:
PMID:9393691
the aruF and aruG genes encode the subunits (AruAI and AruAII) of arginine and ornithine N2-succinyltransferases.
file:PSEPK/astA-I/astA-I-uniprot.txt
NCBIfam; TIGR03244; arg_catab_AstA; 1.
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.

Core Functions

Beta-like component of the split arginine/ornithine N-succinyltransferase that initiates the bacterial AST catabolic pathway.

Directly Involved In:
L-arginine catabolic process
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:PSEPK/astA-I/astA-I-uniprot.txt
    NCBIfam; TIGR03244; arg_catab_AstA; 1.
  • file:PSEPK/astA-I/astA-I-bioinformatics/RESULTS.md
    Q88EI3 is therefore beta-like and Q88EI2 is alpha-like.

References

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Suggested Questions for Experts

Q: Does Q88EI3 contribute catalytic residues, assembly contacts, or both to the KT2440 AstA heterotetramer?

Suggested experts: bacterial arginine catabolism

Suggested Experiments

Experiment: Co-express Q88EI3 and Q88EI2, purify the assembled enzyme, and compare activity with each chain expressed alone.

Type: complex reconstitution and enzyme assay

📚 Additional Documentation

Notes

(astA-I-notes.md)

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Bioinformatics Results

(RESULTS.md)

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