Gene Ontology annotation through association of InterPro records with GO terms
Electronic Gene Ontology annotations created by transferring manual GO annotations between related proteins based on shared sequence features
TreeGrafter-generated GO annotations
Combined Automated Annotation using Multiple IEA Methods
UniProtKB reviewed entry for moaA
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The reviewed HAMAP record identifies Q88E69 as the two-cluster radical-SAM GTP 3',8'-cyclase EC 4.1.99.22.
"CC -!- FUNCTION: Catalyzes the cyclization of GTP to (8S)-3',8-cyclo-7,8-
CC dihydroguanosine 5'-triphosphate. {ECO:0000255|HAMAP-Rule:MF_01225}.
CC -!- CATALYTIC ACTIVITY:
CC Reaction=GTP + AH2 + S-adenosyl-L-methionine = (8S)-3',8-cyclo-7,8-
CC dihydroguanosine 5'-triphosphate + 5'-deoxyadenosine + L-methionine +
CC A + H(+); Xref=Rhea:RHEA:49576, ChEBI:CHEBI:13193, ChEBI:CHEBI:15378,
CC ChEBI:CHEBI:17319, ChEBI:CHEBI:17499, ChEBI:CHEBI:37565,
CC ChEBI:CHEBI:57844, ChEBI:CHEBI:59789, ChEBI:CHEBI:131766;
CC EC=4.1.99.22; Evidence={ECO:0000255|HAMAP-Rule:MF_01225};
CC -!- COFACTOR:
CC Name=[4Fe-4S] cluster; Xref=ChEBI:CHEBI:49883;
CC Evidence={ECO:0000255|HAMAP-Rule:MF_01225};
CC Note=Binds 2 [4Fe-4S] clusters. Binds 1 [4Fe-4S] cluster coordinated
CC with 3 cysteines and an exchangeable S-adenosyl-L-methionine and 1
CC [4Fe-4S] cluster coordinated with 3 cysteines and the GTP-derived
CC substrate. {ECO:0000255|HAMAP-Rule:MF_01225};"
The tetrahydropyranopterin structure of the sulfur-free and metal-free molybdenum cofactor precursor.
Binding of 5'-GTP to the C-terminal FeS cluster of the radical S-adenosylmethionine enzyme MoaA provides insights into its mechanism.
Identification of a cyclic nucleotide as a cryptic intermediate in molybdenum cofactor biosynthesis.
OpenScientist gene research for moaA
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The report gives the canonical MoaA reaction assignment, independently supported by reviewed Q88E69 UniProt.
"MoaA is a **radical S-adenosyl-L-methionine (SAM) metalloenzyme, GTP 3',8-cyclase**, that catalyzes the **first and committed step of molybdenum cofactor (Moco) biosynthesis**."
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The report correctly distinguishes MoaA cyclization from the cyclic-phosphate-forming MoaC reaction.
"MoaA is **not** the enzyme that forms the cyclic phosphate or releases pyrophosphate (that is MoaC)"
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The report presents target-specific residue analysis that was not saved as a reproducible local artifact.
"**N-terminal radical-SAM cluster:** the canonical **CX₃CX₂C** motif at **Cys27–Cys31–Cys34** (…C27-D-F-R-C31-V-Y-C34…), matching the SAM-cleaving [4Fe-4S] cluster fingerprint (IPR000385)."
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The report explicitly acknowledges that its mechanistic and structural evidence is transferred from orthologs.
"All mechanistic/structural data derive from **orthologs**, not the *P. putida* KT2440 protein directly; however, MoaA family conservation (HAMAP MF_01225) makes transfer of annotation robust."
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The report overstates Q88E69 as rate-defining despite unresolved KT2440 MoaA-family paralogs.
"Because MoaA sits at the pathway's entry point, its activity is **rate-defining for the supply of all Moco-dependent enzymes**"
Reproducible sequence comparison of KT2440 MoaA-family and MobA-like proteins
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Q88E69 alone carries the MoaA-specific InterPro records among the three KT2440 MoaA-family candidates examined.
"- The reviewed MoaA sequence Q88E69 is the only one of the three with the
MoaA-specific InterPro entries IPR013483 and IPR000385 in its UniProt record.
All three share broader MoaA-like/radical-SAM entries and PTHR22960."