GatC is a 93-residue GatC-family subunit of the heterotrimeric tRNA-dependent amidotransferase in Methanothrix thermoacetophila PT. Its conserved role is to contribute to GatCAB assembly and charged-tRNA amino-acid modification. Family assignment and comparative archaeal biology support a role in Asn-tRNA formation from Asp-tRNA; the native substrate range and physiological pathway allocation in this species are not experimentally established.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0000166 nucleotide binding | IEA GO_REF:0000043 | MARK AS OVER ANNOTATED | Summary: Complex ATP use does not establish nucleotide binding by the GatC subunit. Reason: The electronic keyword transfer exceeds the inspected subunit evidence. The target is assigned to the small GatC accessory family and the curated reaction belongs to the heterotrimer; no target GatC nucleotide-binding site or binding assay is established. This does not experimentally exclude an uncharacterized binding interaction. Supporting Evidence: file:METTP/gatC/gatC-uniprot.txt Belongs to the GatC family. file:METTP/gatC/gatC-uniprot.txt Heterotrimer of A, B and C subunits. |
| GO:0005524 ATP binding | IEA GO_REF:0000043 | MARK AS OVER ANNOTATED | Summary: Complex ATP use does not establish nucleotide binding by the GatC subunit. Reason: The electronic keyword transfer exceeds the inspected subunit evidence. The target is assigned to the small GatC accessory family and the curated reaction belongs to the heterotrimer; no target GatC nucleotide-binding site or binding assay is established. This does not experimentally exclude an uncharacterized binding interaction. Supporting Evidence: file:METTP/gatC/gatC-uniprot.txt Belongs to the GatC family. file:METTP/gatC/gatC-uniprot.txt Heterotrimer of A, B and C subunits. |
| GO:0006412 translation | IEA GO_REF:0000120 | MODIFY | Summary: GatC contributes to modification of an amino acid already attached to tRNA. Reason: The supported mechanistic process is charged-tRNA amino acid modification. GO:0070681 is obsolete, and its Gln-specific native-pathway interpretation is not established for Methanothrix. Comparative archaeal evidence assigns GatCAB to Asn-tRNA formation and distinguishes GatDE-mediated Gln-tRNA formation. The target family assignment supports the GatCAB contribution by homology, not a target-specific substrate assay. Proposed replacements: charged-tRNA amino acid modification Supporting Evidence: file:METTP/gatC/gatC-uniprot.txt Belongs to the GatC family. file:METTP/gatC/gatC-uniprot.txt Allows the formation of correctly charged Asn-tRNA(Asn) or Gln-tRNA(Gln) through the transamidation of misacylated Asp-tRNA(Asn) or Glu-tRNA(Gln) PMID:25548166 In archaea, GatCAB is used only for Asn-tRNA Asn formation as GatDE forms Gln-tRNA Gln |
| GO:0006450 regulation of translational fidelity | IEA GO_REF:0000002 | UNDECIDED | Summary: A distinct regulatory role in translational fidelity is not established for this target. Reason: The prior rationale transferred Mycobacterium regulatory findings to a different archaeal target without establishing their applicability. Participation in charged-tRNA synthesis supports substrate supply, but does not by itself resolve the separate regulation claim. No independent target evidence for regulation was verified; retain uncertainty. Supporting Evidence: file:METTP/gatC/gatC-uniprot.txt Belongs to the GatC family. file:METTP/gatC/gatC-uniprot.txt Allows the formation of correctly charged Asn-tRNA(Asn) or Gln-tRNA(Gln) through the transamidation of misacylated Asp-tRNA(Asn) or Glu-tRNA(Gln) |
| GO:0016874 ligase activity | IEA GO_REF:0000043 | MODIFY | Summary: Refine the broad ligase contribution to the supported GatCAB Asn-forming activity. Reason: GatC contributes as an accessory subunit to the assembled amidotransferase. Lack of an independent catalytic site is not grounds to reject the complex activity. The target curated GatC/heterotrimer assignment and comparative archaeal pathway support the Asn-forming contribution by homology. Proposed replacements: asparaginyl-tRNA synthase (glutamine-hydrolyzing) activity Supporting Evidence: file:METTP/gatC/gatC-uniprot.txt Belongs to the GatC family. file:METTP/gatC/gatC-uniprot.txt Heterotrimer of A, B and C subunits. PMID:25548166 In archaea, GatCAB is used only for Asn-tRNA Asn formation as GatDE forms Gln-tRNA Gln |
| GO:0050566 asparaginyl-tRNA synthase (glutamine-hydrolyzing) activity | IEA GO_REF:0000116 | ACCEPT | Summary: GatC contributes to the Asn-forming activity of the GatCAB complex. Reason: The target curated HAMAP assignment supports GatC membership and Asn-tRNA transamidation capacity. Comparative archaeal biology supports this pathway allocation. The annotation is a complex contribution, not independent GatC catalysis or a native Methanothrix assay. Supporting Evidence: file:METTP/gatC/gatC-uniprot.txt Belongs to the GatC family. file:METTP/gatC/gatC-uniprot.txt Allows the formation of correctly charged Asn-tRNA(Asn) or Gln-tRNA(Gln) through the transamidation of misacylated Asp-tRNA(Asn) or Glu-tRNA(Gln) file:METTP/gatC/gatC-uniprot.txt Heterotrimer of A, B and C subunits. PMID:25548166 In archaea, GatCAB is used only for Asn-tRNA Asn formation as GatDE forms Gln-tRNA Gln |
| GO:0050567 glutaminyl-tRNA synthase (glutamine-hydrolyzing) activity | IEA GO_REF:0000120 | UNDECIDED | Summary: The Gln-forming biochemical capacity of this target GatCAB remains unresolved. Reason: The curated HAMAP record includes a broad Gln-forming reaction, but comparative archaeal biology distinguishes native GatCAB Asn formation from GatDE Gln formation. Neither that pathway division nor GatC noncatalytic status disproves an in vitro Gln-forming capacity. The prior manual report concerns a different organism, and no target-specific substrate evidence resolves this claim. Supporting Evidence: file:METTP/gatC/gatC-uniprot.txt Allows the formation of correctly charged Asn-tRNA(Asn) or Gln-tRNA(Gln) through the transamidation of misacylated Asp-tRNA(Asn) or Glu-tRNA(Gln) PMID:25548166 In archaea, GatCAB is used only for Asn-tRNA Asn formation as GatDE forms Gln-tRNA Gln |
| GO:0070681 glutaminyl-tRNAGln biosynthesis via transamidation | IEA GO_REF:0000118 | MODIFY | Summary: GatC contributes to modification of an amino acid already attached to tRNA. Reason: The supported mechanistic process is charged-tRNA amino acid modification. GO:0070681 is obsolete, and its Gln-specific native-pathway interpretation is not established for Methanothrix. Comparative archaeal evidence assigns GatCAB to Asn-tRNA formation and distinguishes GatDE-mediated Gln-tRNA formation. The target family assignment supports the GatCAB contribution by homology, not a target-specific substrate assay. Proposed replacements: charged-tRNA amino acid modification Supporting Evidence: file:METTP/gatC/gatC-uniprot.txt Belongs to the GatC family. file:METTP/gatC/gatC-uniprot.txt Allows the formation of correctly charged Asn-tRNA(Asn) or Gln-tRNA(Gln) through the transamidation of misacylated Asp-tRNA(Asn) or Glu-tRNA(Gln) PMID:25548166 In archaea, GatCAB is used only for Asn-tRNA Asn formation as GatDE forms Gln-tRNA Gln |
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Download this section (compressed HTML)Q: Does native Methanothrix thermoacetophila GatCAB support only Asp-tRNA(Asn) amidation, or also a measurable Glu-tRNA(Gln) capacity?
Experiment: Reconstitute the native Methanothrix GatCAB heterotrimer and compare Asp-tRNA(Asn) and Glu-tRNA(Gln) substrates; distinguish substrate capacity from native pathway use.
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Download this section (compressed HTML)A0B5K3 is Methanothrix thermoacetophila PT (Mthe_0178, taxon 349307). The prior manual report instead applied Methanothermobacter thermautotrophicus findings. That report is preserved and flagged as miscited. Target HAMAP GatC-family and heterotrimer assignments support a complex contribution by homology; PMID:25548166 supplies comparative archaeal Asn/Gln pathway context. Native substrate range and regulatory effects remain unresolved. The eight original machine annotation payloads are preserved. Two unsupported inherited NEW adaptor/protein-binding proposals are archived in gatC-source-analysis/retired-proposals-2026-10-29.yaml and retired from the active review. No new annotation is proposed.
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