A0A1D5AG16 · PIGJ_MONRU

  • Protein
    Fatty acid synthase alpha subunit pigJ
  • Gene
    pigJ
  • Status
    UniProtKB reviewed (Swiss-Prot)
  • Amino acids
  • Protein existence
    Evidence at protein level
  • Annotation score
    5/5

Function

function

Fatty acid synthase alpha subunit; part of the gene cluster that mediates the biosynthesis of azaphilone pigments (MonAzPs), a complex mixture of compounds with a common azaphilone skeleton very widely used as food colorants (PubMed:26946170, PubMed:28959415, PubMed:34220766).
PigJ and pigK form the two subunits of a dedicated fungal fatty acid synthase (FAS) that produces the side chain fatty acyl moiety of MonAzPs, a beta-keto fatty acid. The chain length control of the pigJ-pigK FAS is somewhat flexible as MonAzPs features either a beta-ketooctanoic or a beta-ketodecanoic acid moiety. The beta-ketoacyl-ACP probably serves as the substrate for the acetyltransferase pigD that directly transfers the fatty acyl chain to the C-4 alcohol of the pyran ring (PubMed:28959415).
The first step of the pathway is performed by the nrPKS pigA that forms the hexaketide precursor from successive condensations of five malonyl-CoA units, with a simple acetyl-CoA starter unit. The role of esterase pigG is not clear, but it may play at most a supplementary role in the formation of the benzaldehyde produced by the pigA nrPKS. This very reactive benzaldehyde is intercepted by the pigC ketoreductase that to provide the first stable enzyme-free MonAzPs intermediate, 6-(4-hydroxy-2-oxopentyl)-3-methyl-2,4-dioxocyclohexane carbaldehyde, also known as M7PKS-1. The FAD-dependent monooxygenase pigN hydroxylates M7PKS-1 at C-4, which triggers the formation of the pyran ring. PigJ, pigK and pigD are involved in the acetylation of the pyran ring. PigJ and pigK form the two subunits of a dedicated fungal FAS that produces the side chain fatty acyl moiety of MonAzPs and pigD transfers the fatty acyl chain to the C-4 alcohol. PigM and pigO are involved in the elimination of the omega-1 alcohol. PigM acts as an O-acetyltransferase that synthesizes the putative O-11 acetyl intermediate whereas pigO eliminates acetic acid to yield an intermediate with a C1011 double bond. The dehydration of the C-11 alcohol followed by the reduction of the C67 double bond by the NAD(P)H-dependent oxidoreductase pigE increases the electrophilicity of the C-5 ketone of the resulting acyl benzopyran. This in turn sets up the C-5 ketone for an intramolecular Knoevenagel aldol condensation with the C-20 enol of the side chain. This condensation affords the characteristic linear tricyclic carbon skeletons of the yellow pigments that serve as the common precursors for the classical yellow pigments monascin and ankaflavin, orange pigments rubopunctatin and monascorubrin, and red pigments ribropunctamine and monascorubramine. The FAD-dependent oxidoreductase pigF is especially invoved in the biosynthesis of orange and red pigments via desaturation of C67 (PubMed:28959415).

Catalytic activity

Biotechnology

As colorants, MonAzPs are widely used in various food products for centuries (PubMed:37087240).
Moreover, MonAzPs also possess wide-ranging biological activities such as antibacterial activity, preventing hypertension, lowering cholesterol levels, causing hypolipidemic effects, and displaying antiobesity and antitumor activities (PubMed:16283302, PubMed:16660141, PubMed:17191930, PubMed:20666456, PubMed:22562164).

Pathway

Secondary metabolite biosynthesis.

Features

Showing features for active site, binding site.

Type
IDPosition(s)Description
Active site1244For beta-ketoacyl synthase activity
Active site1470For beta-ketoacyl synthase activity
Active site1511For beta-ketoacyl synthase activity
Binding site1725Mg2+ (UniProtKB | ChEBI)
Binding site1725-1727acetyl-CoA (UniProtKB | ChEBI)
Binding site1726Mg2+ (UniProtKB | ChEBI)
Binding site1727Mg2+ (UniProtKB | ChEBI)
Binding site1761acetyl-CoA (UniProtKB | ChEBI)
Binding site1770-1780acetyl-CoA (UniProtKB | ChEBI)
Binding site1823-1825acetyl-CoA (UniProtKB | ChEBI)
Binding site1824Mg2+ (UniProtKB | ChEBI)
Binding site1825Mg2+ (UniProtKB | ChEBI)

GO annotations

AspectTerm
Cellular Componentfatty acid synthase complex
Molecular Function3-oxoacyl-[acyl-carrier-protein] reductase (NADPH) activity
Molecular Function3-oxoacyl-[acyl-carrier-protein] synthase activity
Molecular Functionfatty acid synthase activity
Molecular Functionholo-[acyl-carrier-protein] synthase activity
Molecular Functionmagnesium ion binding
Molecular Functionpigment binding
Biological Processlong-chain fatty acid biosynthetic process

Keywords

Enzyme and pathway databases

Names & Taxonomy

Protein names

  • Recommended name
    Fatty acid synthase alpha subunit pigJ
  • EC number

Including 2 domains:

  • Recommended name
    3-oxoacyl-[acyl-carrier-protein] reductase
  • EC number
  • Alternative names
    • Beta-ketoacyl reductase
  • Recommended name
    3-oxoacyl-[acyl-carrier-protein] synthase
  • EC number
  • Alternative names
    • Azaphilone pigments biosynthesis cluster protein J

Gene names

    • Name
      pigJ

Organism names

  • Taxonomic identifier
  • Strain
    • M7
  • Taxonomic lineage
    Eukaryota > Fungi > Dikarya > Ascomycota > Pezizomycotina > Eurotiomycetes > Eurotiomycetidae > Eurotiales > Aspergillaceae > Monascus

Accessions

  • Primary accession
    A0A1D5AG16

Subcellular Location

Phenotypes & Variants

Disruption phenotype

Leads to the accumulation of pyran intermediates devoid of the medium-chain fatty acyl moiety such as monascusone A.

PTM/Processing

Features

Showing features for chain, modified residue.

Type
IDPosition(s)Description
ChainPRO_00004602031-1842Fatty acid synthase alpha subunit pigJ
Modified residue222O-(pantetheine 4'-phosphoryl)serine

Keywords

Expression

Induction

Expression does not seem to be regulated by the azaphilone pigments (MonAzPs) gene cluster-specific transcription regulator pigB.

Interaction

Subunit

[Alpha6beta6] hexamers of two multifunctional subunits (alpha and beta).

Structure

3D structure databases

Family & Domains

Features

Showing features for region, compositional bias, domain.

Type
IDPosition(s)Description
Region120-184Disordered
Compositional bias140-182Polar residues
Domain184-262Carrier
Region611-807Beta-ketoacyl reductase
Domain1058-1585Ketosynthase family 3 (KS3)
Region1649-1672Disordered
Compositional bias1655-1672Polar residues

Sequence similarities

Family and domain databases

Sequence

  • Sequence status
    Complete
  • Length
    1,842
  • Mass (Da)
    199,882
  • Last updated
    2016-11-30 v1
  • Checksum
    F1CFA1727F134240
MAVRKLVPETAPVVDDAPASTSVDHKRSLAHKLLIELLSYQLALPVRWIETQNELLQWPETIQRYVEVGPRTTLVTMAKKTAARRASSQIVSASKLSTLKFLCTSDNTAEIYYEYPQESGAPVEEEGSKSDAAAPALAVSGSSRTATTAKATVTTPSSSSPETAPPAASTPSQGTPAGGSTTPDIPLSAKHVVLAMIAQKFRRAFDNIPTQKTVQELSGGKSTLQNEIMGDLAVEFGQLPDGGEYIPLDALGDALQGNFPGKPGKQMSSLITKLISRKMPGGFNQAAMQNHLEREWGFSKAHGQVVICLAITVEPESRLESADSAREFLDGLVSRYASYAGITMTPRGKGNVSADHSSAVMVDESVLNGIKREQRDYQIKELELLSKHLQLDTAADDAVLNELRASQKSLEEKLDRWASEFDDKFFSGIEAIFDARKVRQYDSWWNWAREDTMRLLSRMRPGQLPLQHLQEQGLVAQLLRRWEPSCAEIVQNFLDTGECKEPFLATAAEILRLGSDALKKSPVYRFTTPSMKPRTVISATGCVEYSEVPRENSSYIALLKQGLVAASGERVPYVHLKKKAPDQAWRYDAQSTEILLEALGTGSGAGLTFSGKTVLVTGAGPNSIGAAVVRGLLNGGAKVIVTTSRSVSSAASFFQRMYRECAARGATMAVVPFNQASKRDCESLVEYIYGAHSPVDGDLDYLVPFGAIPEKVELSKLDGASELAHRAMLVNILRILGLVYKEKEQRGLRTRPTTVIVPLSFNLGGFGGDGLYPESKIGLEALFNRYFSGNWSDYLSICGAAIGWVRGTTLSQSIRLLGEAIEHANGLDVITFSQEEMAFNILALMTPSIAETCEEGPVYADLTGGAKAIANIKDVMAAARAKFLKESSIQKALLAERAYEQRVLYGSESPRNDTSSPRPRLSTKRARLSLEFPEVPSKSDLKAHLVDLQGMVDLSRTVVVVGFSELGPWGNARTRWQMEHLTDLTPEGYIEMAWIMGLVEHFQGHLDGKPFVGWVDAQTKQPVADAEFKEKYQAHILAHAGLRFVEPDLLGGYDPSKKEFLQEIVVEEALPSFSTSKANADAFRLRLGDKVAVRRMPESDEYLVQVKRGAHFFVPKAVPFNRGVAGLLPAGWDPLRYGIPEDIVQQVDPVTLYALCCVSEALLSAGIRDPYELYRYIHVSELANCLGTGAGAQSAAQRLYKKRYLDHAVQSDILSESFLNTTAAWVNMLVFSSTGPIKTPVGACATAIESLDIGCDAIRSGRSQVALVGGYDDFREEASYEFAMMNATASSVGELAQGRLPREMSRPSTTTRGGFVESAGCGVQLIMNAELAIEMGLPIHAIIAYTQMAGDKIGRSIPAPGQGILTAARETSAGHDSALLDLAHRRKRLTDEVDAVHQWVTQQLAATRGPAGWPDRAIDEIEATALRKIKHAQHAWGNDIRCQDPSISPLKASLATWGLTIDDVQVVSMHGTSTKANDTNEADVISQQMDHLGRRPGNPLLAVCQKALTGHPKGAAGAWQLHGCMQMLQTGIVPGNRNADNIDSKLRQHRHIVYPMESMPMPQLKAAMLTSFGFGQKGGIAVVVAARHLFSAMAEDELEAYRRRVAKRQREADSAYVSGIMSKSLFKAKEVSVWGKSDASMSRMLLDPKARVGGHPENNNNNNNNSSSKRNTSIERLTRLLLPSQKPETEASPEGQQSTSLTASIQALLASQSTTRPTSTSIGVDVEAISSIPMGNAVFLERNFTRSERDHCFSSPTPQASFAGRWSAKEAVFKSLQTPSVGAGAAMAEIEIVSDGGVPKVQLHGRAKEVALAKGIRNIQASITHSGETVTAVALAESSPMC

Features

Showing features for compositional bias.

TypeIDPosition(s)Description
Compositional bias140-182Polar residues
Compositional bias1655-1672Polar residues

Sequence databases

Nucleotide SequenceProtein SequenceMolecule TypeStatus
JX675042
EMBL· GenBank· DDBJ
AGL44429.1
EMBL· GenBank· DDBJ
Genomic DNA

Similar Proteins

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