QuiP (PA1032, quorum signal utilization and inactivation protein) is a peptidase S45 (penicillin acylase family) N-terminal nucleophile hydrolase with a predicted signal peptide, thought to be processed into alpha and beta subunits in the periplasm. It is an acyl-homoserine lactone (AHL) acylase (EC 3.5.1.97) that cleaves the amide bond of AHLs with acyl chains of seven or more carbons, releasing homoserine lactone and the fatty acid; short-chain AHLs such as C4-HSL are not degraded. QuiP is the acylase that lets P. aeruginosa grow on long-chain AHLs, including its own signal 3-oxo-C12-HSL, as sole carbon and energy source. It is induced during growth on long-chain AHLs, and constitutive expression lowers 3-oxo-C12-HSL accumulation, giving QuiP a potential role in quorum quenching.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0016787 hydrolase activity | IEA GO_REF:0000002 | TOO GENERAL | Summary: True but uninformative; GO:0016811, accepted below, is a descendant. Reason: GO:0016811 is_a GO:0016810 is_a GO:0016787 and is accepted in this review. |
| GO:0016811 hydrolase activity, acting on carbon-nitrogen (but not peptide) bonds, in linear amides | IBA GO_REF:0000033 | ACCEPT | Summary: IBA from the PTN002151232 IBD, seeded by the three PAO1 AHL acylases PvdQ, QuiP and PA0305. QuiP's own experimental row is one of the seeds, which is expected and not circular. All three seeds show the activity directly. Reason: Sound IBD; GO:0016811 is the most specific existing GO term for AHL acylase and suits the 21-leaf Ntn acylase clade (node record in the pvdQ notes). Supporting Evidence: PMID:16461666 The results confirm that quiP encodes a protein with acyl-HSL acylase activity. |
| GO:0016811 hydrolase activity, acting on carbon-nitrogen (but not peptide) bonds, in linear amides | IEA GO_REF:0000002 | ACCEPT | Summary: InterPro2GO mapping from the Pen/GL7ACA/AHL acylase signatures; agrees with the experimental row. Reason: Consistent with the IMP and IBA rows on the same term. Supporting Evidence: PMID:16461666 The results confirm that quiP encodes a protein with acyl-HSL acylase activity. |
| GO:0016811 hydrolase activity, acting on carbon-nitrogen (but not peptide) bonds, in linear amides | IMP PMID:16461666 Identification of QuiP, the product of gene PA1032, as the s... | ACCEPT | Summary: PseudoCAP seed of PTN002151232. The quiP mutant cannot grow on C10-HSL, and E. coli expressing quiP gains long-chain AHL acylase activity with HSL as product (full text read). Reason: Directly supported; GO:0016811 is the most specific existing term for AHL acylase (a specific term is proposed in the pvdQ review). Supporting Evidence: PMID:16461666 The results confirm that quiP encodes a protein with acyl-HSL acylase activity. PMID:16461666 Transposon mutants of quiP were defective for growth when P. aeruginosa was cultured in medium containing decanoyl-HSL as a sole carbon and energy source. |
| GO:0017000 antibiotic biosynthetic process | IEA GO_REF:0000002 | REMOVE | Summary: InterPro2GO mapping from the peptidase S45 signature, reflecting the industrial use of penicillin acylases. QuiP is an AHL acylase used for signal degradation and catabolism; nothing links it to antibiotic synthesis. Reason: Over-propagated family mapping; QuiP's demonstrated role is AHL degradation and utilization, not antibiotic biosynthesis. Supporting Evidence: PMID:16461666 The results confirm that quiP encodes a protein with acyl-HSL acylase activity. |
| GO:0042597 periplasmic space | IEA GO_REF:0000044 | ACCEPT | Summary: Predicted from the N-terminal signal sequence and from periplasmic family members such as PvdQ. Reason: Plausible location by signal peptide and family; not directly assayed. Supporting Evidence: PMID:16461666 PA1032 is predicted to be secreted into the periplasm based on its signal sequence |
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Download this section (compressed HTML)Q: What natural conditions induce quiP, and is AHL degradation by QuiP used for nutrition, for signal turnover, or both?
Experiment: Purify mature QuiP and measure kinetics across AHL chain lengths, and test its periplasmic location by fractionation.
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