moeB encodes the cytosolic molybdopterin-synthase sulfur-carrier adenylyltransferase. MoeB uses ATP to adenylate the C-terminal glycine of MoaD, activating the carrier for thiocarboxylate formation and subsequent sulfur donation during molybdopterin synthesis.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0003824 catalytic activity | IEA GO_REF:0000117 | MODIFY | Summary: Replace the uninformative catalytic-activity ancestor with the supported specific reaction. Reason: Catalysis is central to this enzyme, but GO:0003824 does not identify the reaction. Use the specific molecular function already supported elsewhere in this review; this is a specificity refinement, not a claim that catalysis is peripheral or absent. Proposed replacements: molybdopterin-synthase adenylyltransferase activity Supporting Evidence: PMID:11713534 MoeB activates the C terminus of MoaD to form an acyl-adenylate. file:PSEPK/moeB/moeB-deep-research-openscientist.md Q88PW3 is therefore a "classic" adenylyltransferase that requires a separate downstream sulfurtransferase to complete thiocarboxylation. |
| GO:0004792 thiosulfate-cyanide sulfurtransferase activity | IEA GO_REF:0000118 | REMOVE | Summary: A thiosulfate-cyanide sulfurtransferase reaction is not supported for MoeB. Reason: MoeB activates MoaD by ATP-dependent adenylylation; it does not use thiosulfate or cyanide in the assigned reaction. The 251-aa target lacks the C-terminal rhodanese domain found in multifunctional MoeB/MoeZ-family fusions; this is an architecture and reaction mismatch, not merely absence of a target assay. Supporting Evidence: file:PSEPK/moeB/moeB-uniprot.txt CC -!- FUNCTION: Catalyzes the adenylation by ATP of the carboxyl group of the CC C-terminal glycine of sulfur carrier protein MoaD. CC {ECO:0000256|ARBA:ARBA00055169}. PMID:11713534 MoeB activates the C terminus of MoaD to form an acyl-adenylate. file:PSEPK/moeB/moeB-deep-research-openscientist.md Q88PW3 is therefore a "classic" adenylyltransferase that requires a separate downstream sulfurtransferase to complete thiocarboxylation. |
| GO:0005737 cytoplasm | IEA GO_REF:0000118 | ACCEPT | Summary: Retain cytoplasmic localization of the soluble MoaD-activation enzyme. Reason: MoeB operates with soluble MoaD in the cytoplasmic molybdenum-cofactor pathway. Cytoplasm and cytosol are compatible core localizations; redundancy does not establish over-annotation. Supporting Evidence: file:PSEPK/moeB/moeB-deep-research-openscientist.md Moco biosynthesis, including the MoeB-catalyzed MoaD-activation step, occurs in the **cytoplasm**. |
| GO:0005829 cytosol | IEA GO_REF:0000118 | ACCEPT | Summary: Retain cytoplasmic localization of the soluble MoaD-activation enzyme. Reason: MoeB operates with soluble MoaD in the cytoplasmic molybdenum-cofactor pathway. Cytoplasm and cytosol are compatible core localizations; redundancy does not establish over-annotation. Supporting Evidence: file:PSEPK/moeB/moeB-deep-research-openscientist.md Moco biosynthesis, including the MoeB-catalyzed MoaD-activation step, occurs in the **cytoplasm**. |
| GO:0008146 sulfotransferase activity | IEA GO_REF:0000118 | REMOVE | Summary: Generic sulfotransferase activity does not describe MoeB chemistry. Reason: MoeB adenylates MoaD; sulfur loading is a separate reaction supplied by a sulfur-donor system. Sulfotransferases transfer sulfate groups; the shared sulfur-pathway context does not confer that chemistry on the MoaD adenylase. Supporting Evidence: file:PSEPK/moeB/moeB-uniprot.txt CC -!- FUNCTION: Catalyzes the adenylation by ATP of the carboxyl group of the CC C-terminal glycine of sulfur carrier protein MoaD. CC {ECO:0000256|ARBA:ARBA00055169}. PMID:11713534 MoeB activates the C terminus of MoaD to form an acyl-adenylate. file:PSEPK/moeB/moeB-deep-research-openscientist.md Q88PW3 is therefore a "classic" adenylyltransferase that requires a separate downstream sulfurtransferase to complete thiocarboxylation. |
| GO:0008641 ubiquitin-like modifier activating enzyme activity | IEA GO_REF:0000002 | REMOVE | Summary: This electronic annotation conflates MoeB-mediated acyl-adenylation with E1-like thiolester-forming modifier activation. Reason: The live GO:0008641 definition requires ATP-dependent formation of a high-energy thiolester bond. Q88PW3 is supported only as the enzyme that adenylates the C-terminal carboxylate of the MoaD sulfur carrier; that acyl-adenylate step does not itself perform the E1 thiolester chemistry specified by the term. Supporting Evidence: file:PSEPK/moeB/moeB-uniprot.txt CC -!- FUNCTION: Catalyzes the adenylation by ATP of the carboxyl group of the CC C-terminal glycine of sulfur carrier protein MoaD. CC {ECO:0000256|ARBA:ARBA00055169}. PMID:11713534 MoeB activates the C terminus of MoaD to form an acyl-adenylate. file:PSEPK/moeB/moeB-deep-research-openscientist.md Q88PW3 is therefore a "classic" adenylyltransferase that requires a separate downstream sulfurtransferase to complete thiocarboxylation. |
| GO:0016779 nucleotidyltransferase activity | IEA GO_REF:0000118 | ACCEPT | Summary: Retain the broad catalytic term describing MoaD adenylation. Reason: ATP-dependent transfer of AMP to the terminal carboxylate of MoaD is catalytic nucleotidyl transfer. The specific molybdopterin-synthase adenylyltransferase term is already retained, and its broad catalytic ancestors remain correct. OpenScientist supports the classical MoeB architecture and conserved mechanism while explicitly noting that Q88PW3 has not been assayed. Supporting Evidence: PMID:11713534 MoeB activates the C terminus of MoaD to form an acyl-adenylate. file:PSEPK/moeB/moeB-deep-research-openscientist.md Q88PW3 is therefore a "classic" adenylyltransferase that requires a separate downstream sulfurtransferase to complete thiocarboxylation. |
| GO:0061605 molybdopterin-synthase adenylyltransferase activity | IEA GO_REF:0000120 | ACCEPT | Summary: This is the exact core molecular function of MoeB. Reason: UniProt supplies the MoaD C-terminal adenylylation reaction and EC 2.7.7.80. Supporting Evidence: file:PSEPK/moeB/moeB-uniprot.txt CC -!- CATALYTIC ACTIVITY: CC Reaction=[molybdopterin-synthase sulfur-carrier protein]-C-terminal CC Gly-Gly + ATP + H(+) = [molybdopterin-synthase sulfur-carrier CC protein]-C-terminal Gly-Gly-AMP + diphosphate; Xref=Rhea:RHEA:43616, CC Rhea:RHEA-COMP:12159, Rhea:RHEA-COMP:12202, ChEBI:CHEBI:15378, CC ChEBI:CHEBI:30616, ChEBI:CHEBI:33019, ChEBI:CHEBI:90618, CC ChEBI:CHEBI:90778; EC=2.7.7.80; CC Evidence={ECO:0000256|ARBA:ARBA00052218}; file:PSEPK/moeB/moeB-deep-research-openscientist.md **The reaction catalyzed is: MoaD-COOβ» + ATP β MoaD-CO-AMP (MoaD-adenylate) + PPα΅’.** |
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Download this section (compressed HTML)Experiment: Measure ATP-dependent Q88NB9 C-terminal adenylylation by purified Q88PW3 and test formation of the transient MoeB-MoaD complex.
Type: enzyme assay and complex analysis
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