ThrS is a cytosolic class-II threonyl-tRNA synthetase that attaches threonine to tRNA(Thr) using ATP. Its conserved N-terminal editing machinery hydrolyzes mischarged Ser-tRNA(Thr), distinguishing productive aminoacylation from post-transfer proofreading and helping maintain translation fidelity.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0000166 nucleotide binding | IEA GO_REF:0000002 | MODIFY | Summary: thrS binds ATP as part of its aminoacylation machinery. Reason: Nucleotide binding is true but broad. The curated threonine reaction and relevant subunit architecture support the more specific ATP-binding claim; this is integral substrate recognition, not a peripheral role. Proposed replacements: ATP binding Supporting Evidence: file:PSEPK/thrS/thrS-uniprot.txt Reaction=tRNA(Thr) + L-threonine + ATP = L-threonyl-tRNA(Thr) + AMP + diphosphate + H(+); Xref=Rhea:RHEA:24624, Rhea:RHEA-COMP:9670, Rhea:RHEA-COMP:9704, ChEBI:CHEBI:15378, ChEBI:CHEBI:30616, ChEBI:CHEBI:33019, ChEBI:CHEBI:57926, ChEBI:CHEBI:78442, ChEBI:CHEBI:78534, ChEBI:CHEBI:456215; EC=6.1.1.3; Evidence={ECO:0000255|HAMAP-Rule:MF_00184}; |
| GO:0004812 aminoacyl-tRNA ligase activity | IEA GO_REF:0000002 | MODIFY | Summary: thrS has a defined role in the substrate-specific catalytic reaction. Reason: Refine the broad activity to the supported threonine-tRNA ligase activity. The exact KT2440 curated family/rule assignment supports function by homology, not a purified-target experiment. Proposed replacements: threonine-tRNA ligase activity Supporting Evidence: file:PSEPK/thrS/thrS-uniprot.txt Reaction=tRNA(Thr) + L-threonine + ATP = L-threonyl-tRNA(Thr) + AMP + diphosphate + H(+); Xref=Rhea:RHEA:24624, Rhea:RHEA-COMP:9670, Rhea:RHEA-COMP:9704, ChEBI:CHEBI:15378, ChEBI:CHEBI:30616, ChEBI:CHEBI:33019, ChEBI:CHEBI:57926, ChEBI:CHEBI:78442, ChEBI:CHEBI:78534, ChEBI:CHEBI:456215; EC=6.1.1.3; Evidence={ECO:0000255|HAMAP-Rule:MF_00184}; file:PSEPK/thrS/thrS-uniprot.txt Belongs to the class-II aminoacyl-tRNA synthetase family. {ECO:0000255|HAMAP-Rule:MF_00184}. |
| GO:0004829 threonine-tRNA ligase activity | IEA GO_REF:0000120 | ACCEPT | Summary: thrS supports its substrate-specific tRNA-ligase activity. Reason: The exact native protein has the corresponding curated HAMAP family/domain and reaction assignment. This supports conserved catalytic capability by homology, not direct KT2440 purification. Supporting Evidence: file:PSEPK/thrS/thrS-uniprot.txt Reaction=tRNA(Thr) + L-threonine + ATP = L-threonyl-tRNA(Thr) + AMP + diphosphate + H(+); Xref=Rhea:RHEA:24624, Rhea:RHEA-COMP:9670, Rhea:RHEA-COMP:9704, ChEBI:CHEBI:15378, ChEBI:CHEBI:30616, ChEBI:CHEBI:33019, ChEBI:CHEBI:57926, ChEBI:CHEBI:78442, ChEBI:CHEBI:78534, ChEBI:CHEBI:456215; EC=6.1.1.3; Evidence={ECO:0000255|HAMAP-Rule:MF_00184}; file:PSEPK/thrS/thrS-uniprot.txt Belongs to the class-II aminoacyl-tRNA synthetase family. {ECO:0000255|HAMAP-Rule:MF_00184}. |
| GO:0005524 ATP binding | IEA GO_REF:0000120 | ACCEPT | Summary: thrS contributes integral ATP recognition to its enzymatic reaction. Reason: ATP binding is an integral biochemical property, not a non-core activity merely because it is binding. The curated reaction/architecture supports it by homology for KT2440. Supporting Evidence: file:PSEPK/thrS/thrS-uniprot.txt Reaction=tRNA(Thr) + L-threonine + ATP = L-threonyl-tRNA(Thr) + AMP + diphosphate + H(+); Xref=Rhea:RHEA:24624, Rhea:RHEA-COMP:9670, Rhea:RHEA-COMP:9704, ChEBI:CHEBI:15378, ChEBI:CHEBI:30616, ChEBI:CHEBI:33019, ChEBI:CHEBI:57926, ChEBI:CHEBI:78442, ChEBI:CHEBI:78534, ChEBI:CHEBI:456215; EC=6.1.1.3; Evidence={ECO:0000255|HAMAP-Rule:MF_00184}; |
| GO:0005737 cytoplasm | IEA GO_REF:0000120 | MODIFY | Summary: thrS acts in the soluble intracellular tRNA-processing system. Reason: The soluble intracellular synthetase acts on cellular tRNAs; refine cytoplasm to the already retained cytosol term. This is a conserved biochemical/localization inference, not native microscopy. Proposed replacements: cytosol Supporting Evidence: file:PSEPK/thrS/thrS-uniprot.txt Cytoplasm {ECO:0000255|HAMAP-Rule:MF_00184}. |
| GO:0005829 cytosol | IEA GO_REF:0000118 | ACCEPT | Summary: thrS acts in the bacterial cytosol. Reason: The conserved soluble enzyme architecture and curated intracellular localization support this core location. Direct KT2440 imaging is not claimed; lack of such an experiment does not make the supported core location peripheral. Supporting Evidence: file:PSEPK/thrS/thrS-uniprot.txt Cytoplasm {ECO:0000255|HAMAP-Rule:MF_00184}. |
| GO:0006418 tRNA aminoacylation for protein translation | IEA GO_REF:0000002 | ACCEPT | Summary: thrS directly supplies aminoacyl-tRNA for protein translation. Reason: The curated threonine–tRNA reaction forms the amino-acid–tRNA ester bond used in translation. This is the current process term, not overannotation merely because a former substrate-specific BP was more detailed. Supporting Evidence: file:PSEPK/thrS/thrS-uniprot.txt Reaction=tRNA(Thr) + L-threonine + ATP = L-threonyl-tRNA(Thr) + AMP + diphosphate + H(+); Xref=Rhea:RHEA:24624, Rhea:RHEA-COMP:9670, Rhea:RHEA-COMP:9704, ChEBI:CHEBI:15378, ChEBI:CHEBI:30616, ChEBI:CHEBI:33019, ChEBI:CHEBI:57926, ChEBI:CHEBI:78442, ChEBI:CHEBI:78534, ChEBI:CHEBI:456215; EC=6.1.1.3; Evidence={ECO:0000255|HAMAP-Rule:MF_00184}; |
| GO:0006435 threonyl-tRNA aminoacylation | IEA GO_REF:0000120 | MODIFY | Summary: thrS contributes to translational tRNA aminoacylation; the old substrate-specific BP is obsolete. Reason: Current QuickGO marks this substrate-specific process obsolete because it restates a molecular function. Preserve the original GOA term while replacing it with GO:0006418; retain substrate specificity in the supported ligase molecular function. Proposed replacements: tRNA aminoacylation for protein translation Supporting Evidence: file:PSEPK/thrS/thrS-uniprot.txt Catalyzes the attachment of threonine to tRNA(Thr) in a two- step reaction: L-threonine is first activated by ATP to form Thr-AMP and then transferred to the acceptor end of tRNA(Thr). Also edits incorrectly charged L-seryl-tRNA(Thr). {ECO:0000255|HAMAP- Rule:MF_00184}. |
| GO:0043039 tRNA aminoacylation | IEA GO_REF:0000002 | MODIFY | Summary: thrS performs a defined chemical step supplying translation substrates. Reason: thrS directly participates in ATP-dependent threonine attachment to tRNA for protein translation. Use the precise translational charging process rather than the broader parent; do not retain obsolete substrate-specific BP terms. Proposed replacements: tRNA aminoacylation for protein translation Supporting Evidence: file:PSEPK/thrS/thrS-uniprot.txt Reaction=tRNA(Thr) + L-threonine + ATP = L-threonyl-tRNA(Thr) + AMP + diphosphate + H(+); Xref=Rhea:RHEA:24624, Rhea:RHEA-COMP:9670, Rhea:RHEA-COMP:9704, ChEBI:CHEBI:15378, ChEBI:CHEBI:30616, ChEBI:CHEBI:33019, ChEBI:CHEBI:57926, ChEBI:CHEBI:78442, ChEBI:CHEBI:78534, ChEBI:CHEBI:456215; EC=6.1.1.3; Evidence={ECO:0000255|HAMAP-Rule:MF_00184}; |
| GO:0043905 L-seryl-tRNA(Thr) hydrolase activity | ISS file:PSEPK/thrS/thrS-uniprot.txt | NEW | Summary: ThrS hydrolyzes mischarged Ser-tRNA(Thr). Reason: The exact curated editing-domain/function assignment supports post-transfer deacylation by homology. Comparative biochemical editing studies establish this catalytic mechanism, not a purified KT2440 rate or an additional charging reaction. The inherited author proposal is corrected from the generic deacylase to the live specific GO:0043905 term; this is an authored-payload exception, not a rewrite of machine GOA. Supporting Evidence: file:PSEPK/thrS/thrS-uniprot.txt Catalyzes the attachment of threonine to tRNA(Thr) in a two- step reaction: L-threonine is first activated by ATP to form Thr-AMP and then transferred to the acceptor end of tRNA(Thr). Also edits incorrectly charged L-seryl-tRNA(Thr). {ECO:0000255|HAMAP- Rule:MF_00184}. |
| GO:0106074 aminoacyl-tRNA metabolism involved in translational fidelity | ISS file:PSEPK/thrS/thrS-uniprot.txt | NEW | Summary: thrS performs tRNA editing that contributes directly to translational fidelity. Reason: This protein itself hydrolyzes a mischarged aminoacyl-tRNA through its conserved editing site, satisfying process participation rather than merely being a substrate or required for translation. Conserved AlaRS/ThrRS deacylation mechanisms support the inherited proposal/annotation; no native error-rate measurement is claimed. Supporting Evidence: file:PSEPK/thrS/thrS-uniprot.txt Catalyzes the attachment of threonine to tRNA(Thr) in a two- step reaction: L-threonine is first activated by ATP to form Thr-AMP and then transferred to the acceptor end of tRNA(Thr). Also edits incorrectly charged L-seryl-tRNA(Thr). {ECO:0000255|HAMAP- Rule:MF_00184}. |
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Experiment: Prepare homologous Ser-tRNA(Thr), quantify its hydrolysis by ThrS and editing-site variants, and measure cognate Thr-tRNA(Thr) stability as a specificity control.
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