ID   EQX3_FUSHE              Reviewed;         377 AA.
AC   S4W887;
DT   30-AUG-2017, integrated into UniProtKB/Swiss-Prot.
DT   16-OCT-2013, sequence version 1.
DT   03-AUG-2022, entry version 11.
DE   RecName: Full=Diels-Alderase fsa2 {ECO:0000303|PubMed:23614392};
DE            EC=5.5.1.- {ECO:0000305|PubMed:23614392};
DE   AltName: Full=Equisetin biosynthesis protein 3 {ECO:0000303|PubMed:23614392};
GN   Name=eqx3 {ECO:0000303|PubMed:23614392};
OS   Fusarium heterosporum.
OC   Eukaryota; Fungi; Dikarya; Ascomycota; Pezizomycotina; Sordariomycetes;
OC   Hypocreomycetidae; Hypocreales; Nectriaceae; Fusarium;
OC   Fusarium heterosporum species complex.
OX   NCBI_TaxID=42747;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA], FUNCTION, AND PATHWAY.
RC   STRAIN=ATCC 74349 / MF6069;
RX   PubMed=23614392; DOI=10.1021/cb400159f;
RA   Kakule T.B., Sardar D., Lin Z., Schmidt E.W.;
RT   "Two related pyrrolidinedione synthetase loci in Fusarium heterosporum ATCC
RT   74349 produce divergent metabolites.";
RL   ACS Chem. Biol. 8:1549-1557(2013).
RN   [2]
RP   FUNCTION.
RX   PubMed=18652469; DOI=10.1021/ja803078z;
RA   Sims J.W., Schmidt E.W.;
RT   "Thioesterase-like role for fungal PKS-NRPS hybrid reductive domains.";
RL   J. Am. Chem. Soc. 130:11149-11155(2008).
CC   -!- FUNCTION: Diels-Alderase; part of the gene cluster that mediates the
CC       biosynthesis of equisetin, a trans-fused decalin-containing tetramic
CC       acid with antimicrobial activity (PubMed:23614392). The PKS module of
CC       eqxS together with the enoylreductase eqxC catalyze the formation of
CC       the polyketide unit which is then conjugated to L-serine by the
CC       condensation domain of the eqxS NRPS module (PubMed:23614392). Activity
CC       of the Dieckmann cyclase domain (RED) results in release of the
CC       Dieckmann product intermediate (PubMed:23614392, PubMed:18652469).
CC       Diels-Alderase eqx3 is involved in endo-selective Diels-Alder
CC       cycloaddition to form the decalin ring, leading to the production of N-
CC       desmethylequisetin also called trichosetin (By similarity). Subsequent
CC       N-methylation is carried out by eqxD to give equisetin
CC       (PubMed:23614392). {ECO:0000250|UniProtKB:A0A0E4AZP0,
CC       ECO:0000269|PubMed:18652469, ECO:0000269|PubMed:23614392}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=(5S)-3-[(2E,6R,8E,10E,12E)-2,6-dimethyltetradeca-2,8,10,12-
CC         tetraenoyl]-5-(hydroxymethyl)pyrrolidine-2,4-dione = trichosetin;
CC         Xref=Rhea:RHEA:67328, ChEBI:CHEBI:142061, ChEBI:CHEBI:169938;
CC         Evidence={ECO:0000250|UniProtKB:A0A0E4AZP0};
CC       PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:67329;
CC         Evidence={ECO:0000250|UniProtKB:A0A0E4AZP0};
CC   -!- PATHWAY: Mycotoxin biosynthesis. {ECO:0000305|PubMed:23614392}.
CC   -!- SIMILARITY: Belongs to the Diels-Alderase family. {ECO:0000305}.
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DR   EMBL; KC439347; AGO86663.1; -; Genomic_DNA.
DR   AlphaFoldDB; S4W887; -.
DR   SMR; S4W887; -.
DR   BioCyc; MetaCyc:MON-21735; -.
DR   GO; GO:0016853; F:isomerase activity; IEA:UniProtKB-KW.
PE   3: Inferred from homology;
KW   Isomerase.
FT   CHAIN           1..377
FT                   /note="Diels-Alderase fsa2"
FT                   /id="PRO_0000441293"
SQ   SEQUENCE   377 AA;  41224 MW;  93AD64D43127BBCE CRC64;
     MSNVTVSVFT LDKSISEEPV LPSSFIPSSG NVFPKFTSAI PKTAWELWYF DGISKDDRSS
     IVIGVTRNAE GLKHGGFKVQ VFVIWADERT WHRDLFFPES VVSIDESGAT EGIWKHATSS
     SSISFSCAGD LSKASLVFDV PGIVQGDMHL EALPGDTGLD TDATLGPSVY YVRPLGRASV
     KAQLSLYSSD ATAAEQFILG TSANGGMDRV WSPLSWPQVM TESYYLRAQV GPYAMQIMRI
     FPPKGSENSE NQPSTMARLY REGQLICAPQ HVVTRDDALI THDSLILSKQ NTSDSGDAVT
     GEYRDKNTGY TVEFVGKGNE EQRWEFQVRH ERIIWNTPTS RPGPDATGNT GFVERLYGGT
     IGESYEGVGT GGQCELS