AtsA (PA0183) is the arylsulfatase (aryl-sulfate sulfohydrolase, EC 3.1.6.1) of Pseudomonas aeruginosa. It hydrolyses aryl sulfate esters such as 4-nitrocatechol sulfate to the phenol and inorganic sulfate, which lets the bacterium use aromatic sulfate esters as a sulfur source. Its synthesis is repressed by sulfate, cysteine or thiocyanate and derepressed under sulfate limitation. It is a soluble, monomeric member of the alkaline-phosphatase-fold sulfatase family that, unlike most sulfatases, lacks a signal peptide and is presumed cytoplasmic. Catalysis depends on a Calpha-formylglycine generated post-translationally from Cys51 and on an active-site Ca2+ ion; the 1.3 A crystal structure shows the formylglycine resting as a hydrate that attacks the sulfur atom of the substrate. In vitro the enzyme also hydrolyses phosphate monoesters with a high rate acceleration, a promiscuous activity of uncertain physiological relevance.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0004065 arylsulfatase activity | IBA GO_REF:0000033 | ACCEPT | Summary: IBA from PTN000819263 (arylsulfatase clade, 6 seeds including human ARSA P15289, ARSL (formerly ARSE) P51690, ARSF P54793, mouse and rat Arsg, and AtsA itself). AtsA appearing in WITH/FROM reflects its own experimental annotation and is expected. Reason: Core activity, shown directly with purified enzyme; the IBD is well seeded. Supporting Evidence: PMID:7744061 An arylsulfatase (EC 3.1.6.1) was extracted from Pseudomonas aeruginosa PAO1 and purified 2700-fold to homogeneity PMID:7744061 a Km of 105 microM for 4-nitrocatecholsulfate file:PSEAE/atsA/atsA-uniprot.txt PF00884; Sulfatase |
| GO:0004065 arylsulfatase activity | IDA PMID:7744061 Purification and characterization of the arylsulfatase synth... | ACCEPT | Summary: PseudoCAP IDA and one of six seeds of the PTN000819263 IBD. Beil et al. purified the enzyme to homogeneity from PAO1 and measured its activity and Km with 4-nitrocatechol sulfate, and cloned atsA by complementation. Reason: Seed is SOUND: direct assay of purified enzyme. Supporting Evidence: PMID:7744061 An arylsulfatase (EC 3.1.6.1) was extracted from Pseudomonas aeruginosa PAO1 and purified 2700-fold to homogeneity PMID:7744061 a Km of 105 microM for 4-nitrocatecholsulfate |
| GO:0004065 arylsulfatase activity | IDA PMID:9748219 Posttranslational formation of formylglycine in prokaryotic ... | ACCEPT | Summary: IDA (UniProt) from Dierks et al.: AtsA expressed in active form restores growth on aromatic sulfates and requires formylglycine generated from Cys51. Reason: Direct activity of the recombinant enzyme, with the catalytic formylglycine identified. Supporting Evidence: PMID:9748219 This protein could be expressed in active form in a sulfatase-deficient strain of P. aeruginosa, thereby restoring growth on aromatic sulfates as sole sulfur source PMID:9748219 Substituting the relevant cysteine by a serine codon in the P. aeruginosa gene led to expression of inactive sulfatase protein, lacking the formylglycine |
| GO:0004065 arylsulfatase activity | IEA GO_REF:0000120 | ACCEPT | Summary: EC 3.1.6.1 / RHEA:17261 mapping; same claim as the experimental rows. Reason: Consistent with direct biochemical evidence. Supporting Evidence: PMID:7744061 An arylsulfatase (EC 3.1.6.1) was extracted from Pseudomonas aeruginosa PAO1 and purified 2700-fold to homogeneity |
| GO:0005737 cytoplasm | IEA GO_REF:0000044 | ACCEPT | Summary: UniProt subcellular location (cytoplasm, ECO:0000305). AtsA lacks the signal peptide found in other arylsulfatases, so it is presumed cytoplasmic; no fractionation study is in the cache. Reason: Sequence-based inference stated by the cloning paper; no conflicting evidence. Supporting Evidence: PMID:7744061 The lack of this signal peptide suggests that the P. aeruginosa arylsulfatase is neither periplasmic nor membrane-associated |
| GO:0008081 phosphoric diester hydrolase activity | IDA PMID:19554727 Efficient catalytic promiscuity in an enzyme superfamily: an... | MARK AS OVER ANNOTATED | Summary: PseudoCAP IDA phosphoric diester hydrolase activity citing Olguin et al. 2008. The title and abstract of that paper describe hydrolysis of phosphate monoesters, not diesters, as a promiscuous second activity of AtsA (kcat 620-fold below the sulfatase activity). Reason: Two problems. The term does not match the cited result (monoester, not diester; GO:0008081 is defined as phosphodiester hydrolysis). And the measured activity is a promiscuous in vitro activity of a dedicated arylsulfatase, of unknown physiological relevance, so it should not stand beside the core function. The fitting term for what this paper measured is GO:0016791 phosphatase activity (phosphoric monoester hydrolysis). Supporting Evidence: PMID:19554727 Besides hydrolyzing sulfate monoesters, this enzyme catalyzes the hydrolysis of phosphate monoesters with multiple turnovers PMID:19554727 Promiscuous phosphatase and original sulfatase activities only differ by a factor of 620 |
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Download this section (compressed HTML)Q: Which aryl sulfate esters does AtsA hydrolyse in the natural environment or host, and does its cytoplasmic location imply that the substrates are first imported?
Q: Does PseudoCAP intend GO:0008081 for a phosphodiester activity reported in the full text of PMID:19554727 or in a later paper, or should the row be re-termed to phosphatase activity?
Experiment: Confirm the subcellular location of AtsA by fractionation with cytoplasmic and periplasmic markers, and profile aryl sulfate uptake in an atsA mutant grown on aromatic sulfates as sole sulfur source.
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