AguB (PA0293) is the N-carbamoylputrescine amidohydrolase of Pseudomonas aeruginosa, a homohexameric member of the nitrilase (carbon-nitrogen hydrolase) superfamily that uses thiol-assisted catalysis. It hydrolyses N-carbamoylputrescine to putrescine, ammonia and CO2, the second step after agmatine deiminase (AguA) in the conversion of agmatine to putrescine. The aguBA genes were first identified through agmatine utilization, and the same enzymes provide the arginine decarboxylase route of putrescine biosynthesis, which is redundant with ornithine decarboxylase (SpeC).
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0006596 polyamine biosynthetic process | IEA GO_REF:0000002 | MODIFY | Summary: InterPro2GO from the N-carbamoylputrescine amidase signature. Reason: Correct but general. AguB makes putrescine directly, and the aguAB speC double mutant is a putrescine auxotroph, so the specific descendant GO:0009446 putrescine biosynthetic process (is_a GO:0006596) is supported. Proposed replacements: putrescine biosynthetic process Supporting Evidence: PMID:12634339 a double mutant of aguAB and speC was a putrescine auxotroph. |
| GO:0016787 hydrolase activity | IEA GO_REF:0000104 | TOO GENERAL | Summary: Generic hydrolase term from UniRule. Reason: Entailed by GO:0050126 N-carbamoylputrescine amidase activity, accepted below. |
| GO:0016811 hydrolase activity, acting on carbon-nitrogen (but not peptide) bonds, in linear amides | IEA GO_REF:0000117 | TOO GENERAL | Summary: ARBA term at the level of the broad PTN000557638 node. Reason: Entailed by GO:0050126 (is_a GO:0016811), accepted below. |
| GO:0050126 N-carbamoylputrescine amidase activity | IBA GO_REF:0000033 | ACCEPT | Summary: IBA from PTN000557706, seeded by Arabidopsis CPA/NLP1 (IDA) and the IMP on Q9I6J8 itself (expected, not circular). The IBD stands without this seed. Reason: Core activity, confirmed with purified AguB. Supporting Evidence: PMID:12634339 AguB was specific to N-carbamoylputrescine and the K(m) and K(cat) values of the enzyme for the substrate were 0.5 mM and 3.3 s(-1), respectively. |
| GO:0050126 N-carbamoylputrescine amidase activity | IEA GO_REF:0000002 | ACCEPT | Summary: InterPro2GO from IPR017755. Reason: Agrees with the experimental and phylogenetic rows. |
| GO:0050126 N-carbamoylputrescine amidase activity | IMP PMID:6423933 Arginine degradation in Pseudomonas aeruginosa mutants block... | ACCEPT | Summary: PseudoCAP seed row from the 1984 agmatine-utilization mutant study. The abstract names aguB as the N-carbamoylputrescine amidohydrolase gene. The genetic basis is indirect, but the term is correct for this gene, as later shown with purified AguB. Reason: Seed verdict SOUND. Supporting Evidence: PMID:6423933 The genes encoding agmatine deiminase (aguA) and N-carbamoylputrescine amidinohydrolase (aguB) were 98% cotransducible PMID:12634339 AguB was specific to N-carbamoylputrescine and the K(m) and K(cat) values of the enzyme for the substrate were 0.5 mM and 3.3 s(-1), respectively. |
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Download this section (compressed HTML)Q: How are the catabolic (agmatine utilization) and biosynthetic roles of the aguBA operon balanced, for example by control of its expression?
Experiment: Mutate the predicted catalytic Cys154 of AguB and test N-carbamoylputrescine hydrolysis in vitro and complementation of an aguB speC double mutant.
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