moaE

UniProt ID: Q88NB8
Organism: Pseudomonas putida (strain ATCC 47054 / DSM 6125 / CFBP 8728 / NCIMB 11950 / KT2440)
Review Status: DRAFT
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Gene Description

moaE encodes the catalytic subunit of molybdopterin synthase. In a complex with sulfur-loaded MoaD carrier subunits, MoaE incorporates two sulfurs into cyclic pyranopterin monophosphate to form molybdopterin during molybdenum-cofactor biosynthesis.

Existing Annotations Review

GO Term Evidence Action Reason
GO:0006777 Mo-molybdopterin cofactor biosynthetic process
IEA
GO_REF:0000002 		ACCEPT
Summary: MoaE catalyzes the molybdopterin-forming step of Mo-cofactor biosynthesis.
Reason: UniProt assigns the MoaD-dependent reaction producing molybdopterin and places it in this pathway.
GO:0030366 molybdopterin synthase activity
IEA
GO_REF:0000120 		ACCEPT
Summary: Molybdopterin synthase activity is the exact core molecular function of MoaE.
Reason: UniProt supplies the sulfur-carrier-dependent Rhea reaction and EC 2.8.1.12.
Supporting Evidence:
file:PSEPK/moaE/moaE-deep-research-openscientist.md
The requirement for the thiocarboxylate form is strict: **only the thiocarboxylated MPT synthase complex is able to convert precursor Z to MPT in vitro** [PMID: 11459846](https://pubmed.ncbi.nlm.nih.gov/11459846/).
GO:0032324 molybdopterin cofactor biosynthetic process
IEA
GO_REF:0000117 		MARK AS OVER ANNOTATED
Summary: This broad process is redundant with the more specific retained Mo-molybdopterin cofactor biosynthetic process annotation.
Reason: GO:0006777 more precisely captures the conserved cofactor-biosynthesis route containing the MoaE molybdopterin-forming step.
GO:1990140 molybdopterin synthase complex
ISS
file:PSEPK/moaE/moaE-uniprot.txt 		NEW
Summary: Q88NB8 is the catalytic subunit of the MoaD2-MoaE2 molybdopterin synthase complex.
Reason: The target UniProt entry explicitly records a heterotetramer containing two MoaD and two MoaE subunits, consistent with the conserved synthase architecture and the paired KT2440 moaD/moaE genes.
Supporting Evidence:
file:PSEPK/moaE/moaE-uniprot.txt
CC -!- SUBUNIT: Heterotetramer of 2 MoaD subunits and 2 MoaE subunits. Also CC stable as homodimer. The enzyme changes between these two forms during CC catalysis. {ECO:0000256|ARBA:ARBA00026066}.

Core Functions

Catalytic subunit of molybdopterin synthase, using two thiocarboxylated MoaD sulfur carriers to convert cPMP to molybdopterin.

Molecular Function:
molybdopterin synthase activity
Directly Involved In:
Mo-molybdopterin cofactor biosynthetic process
In Complex:
molybdopterin synthase complex
Supporting Evidence:
  • file:PSEPK/moaE/moaE-uniprot.txt
    CC -!- SUBUNIT: Heterotetramer of 2 MoaD subunits and 2 MoaE subunits. Also CC stable as homodimer. The enzyme changes between these two forms during CC catalysis. {ECO:0000256|ARBA:ARBA00026066}.
  • file:PSEPK/moaE/moaE-uniprot.txt
    CC Reaction=2 [molybdopterin-synthase sulfur-carrier protein]-C-terminal- CC Gly-aminoethanethioate + cyclic pyranopterin phosphate + H2O = CC molybdopterin + 2 [molybdopterin-synthase sulfur-carrier protein]-C- CC terminal Gly-Gly + 2 H(+); Xref=Rhea:RHEA:26333, Rhea:RHEA- CC COMP:12202, Rhea:RHEA-COMP:19907, ChEBI:CHEBI:15377, CC ChEBI:CHEBI:15378, ChEBI:CHEBI:58698, ChEBI:CHEBI:59648, CC ChEBI:CHEBI:90778, ChEBI:CHEBI:232372; EC=2.8.1.12; CC Evidence={ECO:0000256|ARBA:ARBA00049878};

References

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Suggested Experiments

Experiment: Reconstitute molybdopterin production with purified Q88NB8 and thiocarboxylated Q88NB9 and quantify substrate turnover.

Type: in vitro enzyme assay

Deep Research

OpenScientist

(moaE-deep-research-openscientist.md)

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