Q5AR50 · ASQG_EMENI
- ProteinFAD-dependent monooxygenase asqG
- GeneasqG
- StatusUniProtKB reviewed (Swiss-Prot)
- Amino acids566 (go to sequence)
- Protein existenceEvidence at protein level
- Annotation score4/5
Function
function
FAD-dependent monooxygenase; part of the gene cluster that mediates the biosynthesis of the aspoquinolone mycotoxins (PubMed:25251934, PubMed:28114276).
Within the pathway, the FAD-dependent monooxygenase asqG catalyzes the epoxidation of the terminal C7'-C8' olefin to produce the intermediate [(1'E)-5'-(3',3'-dimethyloxiran-2'-yl)-3'-hydroxy-3'-methylpent-1'-en-1'-yl]-quinolinone B (PubMed:28114276).
The first step of the pathway is catalyzed by the nonribosomal peptide synthetase asqK that condenses anthranilic acid and O-methyl-L-tyrosine to produce 4'-methoxycyclopeptin. 4'-methoxycyclopeptin is then converted to 4'-methoxydehydrocyclopeptin by the ketoglutarate-dependent dioxygenase asqJ. AsqJ also converts its first product 4'-methoxydehydrocyclopeptin to 4'-methoxycyclopenin. The following conversion of 4'-methoxycyclopenin into 4'-methoxyviridicatin is catalyzed by the cyclopenase asqI. 4'-methoxyviridicatin is the precursor of quinolone natural products, and is further converted to quinolinone B. The prenyltransferase asqH1 then catalyzes the canonical Friedel-Crafts alkylation of quinolinone B with dimethylallyl cation to yield dimethylallyl quinolone, which is subjected to FAD-dependent dehydrogenation by the FAD-linked oxidoreductase asqF to yield conjugated aryl diene. The delta(3') double bond then serves as the site of the second alkylation with DMAPP catalyzed by the prenyltransferase asqH2 to yield a carbenium ion intermediate, which can be attacked by H2O to yield a styrenyl quinolone containing a C3'-hydroxyprenyl chain. The FAD-dependent monooxygenase asqG performs epoxidation of the terminal C7'-C8' olefin. Finally, after dehydratation of the epoxide at C3 by asqC, the quinolone epoxide rearrangement protein asqO catalyzes an enzymatic 3-exo-tet cyclization to yield the cyclopropyl-THF ring system in aspoquinolone (Probable).
Within the pathway, the FAD-dependent monooxygenase asqG catalyzes the epoxidation of the terminal C7'-C8' olefin to produce the intermediate [(1'E)-5'-(3',3'-dimethyloxiran-2'-yl)-3'-hydroxy-3'-methylpent-1'-en-1'-yl]-quinolinone B (PubMed:28114276).
The first step of the pathway is catalyzed by the nonribosomal peptide synthetase asqK that condenses anthranilic acid and O-methyl-L-tyrosine to produce 4'-methoxycyclopeptin. 4'-methoxycyclopeptin is then converted to 4'-methoxydehydrocyclopeptin by the ketoglutarate-dependent dioxygenase asqJ. AsqJ also converts its first product 4'-methoxydehydrocyclopeptin to 4'-methoxycyclopenin. The following conversion of 4'-methoxycyclopenin into 4'-methoxyviridicatin is catalyzed by the cyclopenase asqI. 4'-methoxyviridicatin is the precursor of quinolone natural products, and is further converted to quinolinone B. The prenyltransferase asqH1 then catalyzes the canonical Friedel-Crafts alkylation of quinolinone B with dimethylallyl cation to yield dimethylallyl quinolone, which is subjected to FAD-dependent dehydrogenation by the FAD-linked oxidoreductase asqF to yield conjugated aryl diene. The delta(3') double bond then serves as the site of the second alkylation with DMAPP catalyzed by the prenyltransferase asqH2 to yield a carbenium ion intermediate, which can be attacked by H2O to yield a styrenyl quinolone containing a C3'-hydroxyprenyl chain. The FAD-dependent monooxygenase asqG performs epoxidation of the terminal C7'-C8' olefin. Finally, after dehydratation of the epoxide at C3 by asqC, the quinolone epoxide rearrangement protein asqO catalyzes an enzymatic 3-exo-tet cyclization to yield the cyclopropyl-THF ring system in aspoquinolone (Probable).
Catalytic activity
- [(1'E)-3'-hydroxy-3',7'-dimethylocta-1',6'-dien-1'-yl]-quinolinone B + H+ + NADPH + O2 = [(1'E)-5'-(3',3'-dimethyloxiran-2'-yl)-3'-hydroxy-3'-methylpent-1'-en-1'-yl]-quinolinone B + H2O + NADP+This reaction proceeds in the forward direction.
Cofactor
Pathway
Secondary metabolite biosynthesis.
Alkaloid biosynthesis.
Mycotoxin biosynthesis.
Features
Showing features for binding site.
GO annotations
Aspect | Term | |
---|---|---|
Cellular Component | membrane | |
Molecular Function | FAD binding | |
Molecular Function | monooxygenase activity | |
Biological Process | secondary metabolite biosynthetic process |
Keywords
- Molecular function
- Ligand
Enzyme and pathway databases
Names & Taxonomy
Protein names
- Recommended nameFAD-dependent monooxygenase asqG
- EC number
- Alternative names
Gene names
Organism names
- Strain
- Taxonomic lineageEukaryota > Fungi > Dikarya > Ascomycota > Pezizomycotina > Eurotiomycetes > Eurotiomycetidae > Eurotiales > Aspergillaceae > Aspergillus > Aspergillus subgen. Nidulantes
Accessions
- Primary accessionQ5AR50
- Secondary accessions
Proteomes
Subcellular Location
UniProt Annotation
GO Annotation
Membrane ; Multi-pass membrane protein
Features
Showing features for transmembrane.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Transmembrane | 448-468 | Helical | ||||
Sequence: ASSTVLWIILMLGMASLGAVW | ||||||
Transmembrane | 482-502 | Helical | ||||
Sequence: GYTLLTLSTFYNLMILFASAV |
Keywords
- Cellular component
PTM/Processing
Features
Showing features for signal, chain.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Signal | 1-19 | |||||
Sequence: MAAFTVIIIGGSISGLTLA | ||||||
Chain | PRO_0000437618 | 20-566 | FAD-dependent monooxygenase asqG | |||
Sequence: NVLEKYGIKYILLEKRPSIGPQLGATVVVHPSGLHLLSQLGLRERVEELATPVELQKAIGPDGTFVLNIAATNQCDRTIADALSTGYMPMFIARQDLIKVLYDNLQDKFRVHASLGLRELEWAGDKVKVTTTDGTSVVGDIVVGADGANSRTRAEIWKIADVEDPSYGSQQLAKSIACTYRCVFGMVDDGDSSLARTAYLAFQYNRAYTYLPTDSGRAYFLAFFKNPAKTVNDAIPRYSDQDEDADVAAHANDIIVPGLTFGDLYKRRTRCTLVPLQEYLLDKCFYKRVVLIGDAVHKLNPITGRGANLAIEGAALLGDLIKHALEKSLQPTDEMLQTAFFTYQQCTKSRAPSQIDDAHRVQSLAALENPLLKFMSLKLLKRATADKLALGVAVDFSTGHSMRYLPQLPQRGMVPLNKDVVANPEHRPASSTVLWIILMLGMASLGAVWQKHQRAEEDQPIHGYTLLTLSTFYNLMILFASAVHGSLGRRAVNLSFSDDSGMVPFYAVGHAPDKYRPTTPSRRVGLLVPGPSYLGSGGHFNGLLEVA |
Interaction
Protein-protein interaction databases
Structure
Sequence
- Sequence statusComplete
- Sequence processingThe displayed sequence is further processed into a mature form.
- Length566
- Mass (Da)61,875
- Last updated2005-04-26 v1
- ChecksumD2B220D263CC2D82
Keywords
- Technical term
Sequence databases
Nucleotide Sequence | Protein Sequence | Molecule Type | Status | |
---|---|---|---|---|
BN001306 EMBL· GenBank· DDBJ | CBF82272.1 EMBL· GenBank· DDBJ | Genomic DNA | ||
AACD01000170 EMBL· GenBank· DDBJ | EAA61521.1 EMBL· GenBank· DDBJ | Genomic DNA |