TesA (PA2856) is a small (201 aa) SGNH/GDSL-family serine hydrolase of Pseudomonas aeruginosa with a Sec signal peptide, closely related to Escherichia coli TesA/TAP (thioesterase I/protease I/lysophospholipase L1). The purified enzyme hydrolyses 1-acyl-sn-glycero-3-phosphocholines (lysophosphatidylcholines with C6, C12 and C16 acyl chains) with high catalytic efficiency, well above its activity on artificial esterase substrates, so lysophospholipase A1 activity is its best-supported physiological activity. It also hydrolyses short-chain p-nitrophenyl esters and Tween detergents, has only low thioesterase activity on palmitoyl-CoA, and no protease activity. Fractionation in P. aeruginosa places TesA mainly in the periplasm, where it has been proposed to keep membrane lysophospholipid levels low. Its crystal structure shows the canonical SGNH alpha/beta/alpha fold with a Ser-Asp-His catalytic triad.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0004064 arylesterase activity | IDA PMID:20931591 Probing enzyme promiscuity of SGNH hydrolases. | KEEP AS NON CORE | Summary: PseudoCAP IDA. Purified TesA hydrolyses p-nitrophenyl (aryl) esters, mainly short-chain ones such as p-nitrophenyl butyrate. Reason: Activity on p-nitrophenyl esters is real, measured on the purified enzyme, and fits the arylesterase definition, but the substrate is artificial; the later study from the same group shows that lysophosphatidylcholine is hydrolysed with about 10- to 100-fold higher catalytic efficiency, and names lysophospholipase A as the likely physiological activity. This row is not a PAINT seed. Supporting Evidence: PMID:20931591 TesA, EstA and EstP were shown to function as esterases with different affinities and catalytic efficacies towards p-nitrophenyl butyrate. PMID:23874889 We previously reported high arylesterase, minor thioesterase and no protease activities for TesA |
| GO:0004064 arylesterase activity | IEA GO_REF:0000117 | KEEP AS NON CORE | Summary: ARBA machine-learning prediction of arylesterase activity. Reason: Consistent with the IDA row on the same term: the activity on aryl esters is experimentally shown but is secondary to lysophospholipase A1 activity. Supporting Evidence: PMID:23874889 We previously reported high arylesterase, minor thioesterase and no protease activities for TesA |
| GO:0004622 phosphatidylcholine lysophospholipase A1 activity | IBA GO_REF:0000033 | ACCEPT | Summary: IBA from PTN000769562 (TesA/TAP clade; 2 seeds, 12 leaf IBAs in 10 taxa). Seeds are E. coli TesA (P0ADA1, IDA for this term) and P. aeruginosa TesA itself (PseudoCAP IDA, PMID:23874889). Reason: The node term suits a small clade of periplasmic TesA/TAP-like SGNH hydrolases, and both seeds have direct biochemical evidence. TesA appearing among its own sources reflects its own experimental annotation, which is expected. The IBD would stand on the E. coli seed alone. Supporting Evidence: PMID:23874889 strongly suggest that lysophospholipase A activity may represent at least one of the physiological functions of TesA |
| GO:0004622 phosphatidylcholine lysophospholipase A1 activity | IDA PMID:23874889 Structural and functional characterisation of TesA - a novel... | ACCEPT | Summary: PseudoCAP IDA, the PTN000769562 seed row. Purified TesA hydrolyses 1-acyl glycerophosphocholines (C6, C12, C16) with Michaelis-Menten kinetics and kcat/Km of 10^5-10^6 per M per s. Reason: Full text read. The substrates assayed are 1-acyl-sn-glycero-3-phosphocholines, the exact substrate of the GO:0004622 reaction, with the purified P. aeruginosa enzyme; the catalytic efficiency is far above that for p-nitrophenyl butyrate. Seed verdict SOUND. Supporting Evidence: PMID:23874889 Lysophospholipase A activities towards 1-hexyl-glycerophosphocholine (C6-GPC), 1-lauryl-glycerophosphocholine (C12-GPC) and 1-palmitoyl-glycerophosphocholine (C16-GPC) were determined over a range of substrate concentrations from 0.5 mM to 5 mM. PMID:23874889 strongly suggest that lysophospholipase A activity may represent at least one of the physiological functions of TesA |
| GO:0004622 phosphatidylcholine lysophospholipase A1 activity | IEA GO_REF:0000117 | ACCEPT | Summary: ARBA prediction of phosphatidylcholine lysophospholipase A1 activity. Reason: Agrees with the direct kinetic evidence on purified TesA. Supporting Evidence: PMID:23874889 strongly suggest that lysophospholipase A activity may represent at least one of the physiological functions of TesA |
| GO:0005576 extracellular region | IEA GO_REF:0000044 | TOO GENERAL | Summary: UniProt subcellular-location mapping from "Secreted" (by similarity, ECO:0000250). Reason: Fractionation in P. aeruginosa places TesA mainly in the periplasm, not the culture supernatant. In GO the periplasmic space is part_of the extracellular region, so the term is true but entailed by GO:0030288 outer membrane-bounded periplasmic space, which this review accepts. The UniProt "Secreted" line would be better as Periplasm. Supporting Evidence: PMID:23874889 These results indicate that TesA is primarily localized in the periplasm. |
| GO:0016042 lipid catabolic process | IBA GO_REF:0000033 | KEEP AS NON CORE | Summary: IBA from the broader SGNH hydrolase node PTN002018599 (seed P42969). Reason: Hydrolysis of lysophospholipids to fatty acid and glycerophosphocholine is lipid catabolism, so the term is consistent with the enzyme's activity. The physiological role (control of membrane lysophospholipid levels) is proposed, not shown, so the process is kept as non-core. Supporting Evidence: PMID:23874889 may point to TesA functioning in the regulation of lysoPL levels |
| GO:0030288 outer membrane-bounded periplasmic space | IBA GO_REF:0000033 | ACCEPT | Summary: IBA periplasm from the E. coli TesA seed (P0ADA1, IDA). Reason: TesA has a 21-residue signal peptide and fractionates mainly to the periplasm in P. aeruginosa, as E. coli TesA does. Supporting Evidence: PMID:23874889 These results indicate that TesA is primarily localized in the periplasm. file:PSEAE/tesA/tesA-uniprot.txt SIGNAL 1..21 |
| GO:0106435 carboxylesterase activity | IBA GO_REF:0000033 | KEEP AS NON CORE | Summary: IBA from PTN002018599, whose only seed for this term is TesA itself (UniProt IDA, PMID:20931591). Reason: Esterase activity on short-chain p-nitrophenyl esters and Tweens is real but secondary to lysophospholipase A1 activity. The seed is a UniProt (not PseudoCAP) row and is experimentally grounded. Supporting Evidence: PMID:20931591 TesA, EstA and EstP were shown to function as esterases with different affinities and catalytic efficacies towards p-nitrophenyl butyrate. |
| GO:0106435 carboxylesterase activity | IDA PMID:20931591 Probing enzyme promiscuity of SGNH hydrolases. | KEEP AS NON CORE | Summary: UniProt IDA for carboxylesterase activity (EC 3.1.1.1) on p-nitrophenyl esters. Reason: Genuine but secondary activity on artificial ester substrates. Supporting Evidence: PMID:20931591 TesA, EstA and EstP were shown to function as esterases with different affinities and catalytic efficacies towards p-nitrophenyl butyrate. |
| GO:0106435 carboxylesterase activity | IEA GO_REF:0000120 | KEEP AS NON CORE | Summary: EC 3.1.1.1 to GO mapping. Reason: Consistent with the IDA row; secondary activity. Supporting Evidence: file:PSEAE/tesA/tesA-uniprot.txt Esterase that exhibits the highest activity towards Tween detergents and p-nitrophenyl esters of short acyl chain length. |
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Download this section (compressed HTML)Q: Does a tesA deletion raise lysophospholipid content in P. aeruginosa membranes, as the proposed role in lysoPL homeostasis predicts?
Experiment: Lipidomics of the periplasm and both membranes in wild type and a tesA deletion, grown with and without membrane stress, to test whether TesA lowers lysophosphatidylcholine and lysophosphatidylethanolamine levels in vivo.
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