PA1486 (bapF) encodes BapF, a beta-peptidyl aminopeptidase of the peptidase S58/DmpA family (MEROPS P01.003). Members of this family are N-terminal-nucleophile hydrolases that autoprocess at a Gly-Ser bond and use the newly exposed serine as the catalytic nucleophile; in BapF this is Ser237. Recombinant BapF releases N-terminal beta-amino acids from beta-peptide substrates such as beta-homoglycine p-nitroanilide, and it also catalyses aminolysis (transpeptidation), forming beta-peptide products that it then hydrolyses. Replacing Ser237 with Cys switches the preferred acyl acceptor from water to amines. Its physiological substrate and role in P. aeruginosa are unknown.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0004177 aminopeptidase activity | IBA GO_REF:0000033 | MODIFY | Summary: PAINT IBA from PTN002194605, whose sole seed is this gene's PseudoCAP IDA (PMID:23728237). The target appearing in its own WITH/FROM is expected. Reason: Aminopeptidase activity is directly shown for recombinant BapF, and it is the characterised activity of the S58/DmpA family (D-aminopeptidases and beta-peptidyl aminopeptidases), so the IBD is sound and the node term is not wrong for the clade. As for the IDA row, the catalytic Ser237 (an N-terminal-nucleophile serine common to the S58/DmpA family) supports the more specific GO:0070009 serine-type aminopeptidase activity for PA1486; substrate-specific terms would not suit a node whose members differ in stereo- and beta-peptide specificity. Propagation Review Root cause: NO FAILURE CORE Sources checked: PANTHER:PTN002194605 ยท PTN002194605 SUPPORTS TRANSFER Worklist (PAINT release used for the PseudoCAP seed worklist) gives 12 leaf IBAs in 12 taxa, all inside the S58/DmpA family (PTHR36512). UniProtKB:Q9I3M6 ยท PA1486 SUPPORTS TRANSFER The target's own experimental annotation is the IBD seed; expected, not circular. Proposed replacements: serine-type aminopeptidase activity Supporting Evidence: PMID:23728237 Recombinant BapF and its S237C mutant exhibited p-nitroaniline release activity toward ฮฒ-homo-Gly-p-nitroanilide (ฮฒhGly-pNA) file:PSEAE/PA1486/PA1486-uniprot.txt Peptidase_S58_DmpA |
| GO:0004177 aminopeptidase activity | IDA PMID:23728237 Mutation of active site serine residue with cysteine display... | MODIFY | Summary: PseudoCAP IDA from the Arima et al. study of recombinant BapF (PA1486) and its active-site Ser237 mutants. Sole seed of the GO:0004177 IBD at PTN002194605. Reason: The paper assays purified recombinant BapF on a beta-peptide p-nitroanilide, which is direct evidence for aminopeptidase activity, so the claim is sound. The same paper identifies Ser237 as the catalytic residue (the Gly236-Ser237 bond is the DmpA-family autoprocessing site in the PA1486 sequence), which supports the more specific GO:0070009 serine-type aminopeptidase activity. GO has no beta-peptidyl aminopeptidase (EC 3.4.11.25) term. Proposed replacements: serine-type aminopeptidase activity Supporting Evidence: PMID:23728237 We specifically examined ฮฒ-peptidyl aminopeptidase of Pseudomonas aeruginosa PAO1 (BapF) to assess the effects of mutation of catalytic Ser with Cys or Thr on its catalytic ability. PMID:23728237 Recombinant BapF and its S237C mutant exhibited p-nitroaniline release activity toward ฮฒ-homo-Gly-p-nitroanilide (ฮฒhGly-pNA) |
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Download this section (compressed HTML)Q: What is the physiological substrate of BapF in P. aeruginosa, given that beta-peptides are rare in nature?
Q: Should GO add a beta-peptidyl aminopeptidase activity term (EC 3.4.11.25) under serine-type aminopeptidase activity?
Experiment: Profile cell-associated and secreted peptide pools in a PA1486 deletion versus wild type to identify natural BapF substrates.
Type: metabolomics/peptidomics
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