ID   AURB_CALAK              Reviewed;         230 AA.
AC   A0A0M4KDW1;
DT   25-APR-2018, integrated into UniProtKB/Swiss-Prot.
DT   09-DEC-2015, sequence version 1.
DT   03-AUG-2022, entry version 12.
DE   RecName: Full=Methyltransferase aurB {ECO:0000303|PubMed:26340065};
DE            EC=2.1.1.- {ECO:0000269|PubMed:26340065};
DE   AltName: Full=Aurovertin biosynthesis cluster protein B {ECO:0000303|PubMed:26340065};
GN   Name=aurB {ECO:0000303|PubMed:26340065};
OS   Calcarisporium arbuscula (Dendryphion arbuscula).
OC   Eukaryota; Fungi; Dikarya; Ascomycota; Pezizomycotina; Sordariomycetes;
OC   Hypocreomycetidae; Hypocreales; Hypocreales incertae sedis; Calcarisporium.
OX   NCBI_TaxID=240499;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA], FUNCTION, DISRUPTION PHENOTYPE,
RP   CATALYTIC ACTIVITY, AND PATHWAY.
RX   PubMed=26340065; DOI=10.1021/jacs.5b07816;
RA   Mao X.M., Zhan Z.J., Grayson M.N., Tang M.C., Xu W., Li Y.Q., Yin W.B.,
RA   Lin H.C., Chooi Y.H., Houk K.N., Tang Y.;
RT   "Efficient biosynthesis of fungal polyketides containing the dioxabicyclo-
RT   octane ring system.";
RL   J. Am. Chem. Soc. 137:11904-11907(2015).
CC   -!- FUNCTION: Methyltransferase; part of the gene cluster that mediates the
CC       biosynthesis of aurovertins, fungal polyketides that exhibit potent
CC       inhibition of adenosine triphosphate synthase (PubMed:26340065). Tha
CC       biosynthesis starts with the HR-PKS aurA that selects propionate as the
CC       starter unit; synthesizes a hexa-ene chain through the repeated
CC       functions of the KR and DH domains in the first six iterations;
CC       selectively introduces three alpha-methyl substitutions at C4, C6, and
CC       C16 using the S-adensylmethionine-dependent cMET; and shuts off KR and
CC       DH in the last three iterations to afford a 1,3,5-triketo portion that
CC       can undergo intramolecular cyclization to yield the alpha-pyrone
CC       intermediate (PubMed:26340065). AurE may act as a cyclase and enhances
CC       the rate of pyrone formation and product release of aurA
CC       (PubMed:26340065). The methyltransferase aurB then methylates the C17
CC       hydroxyl group (PubMed:26340065). C17 methylation is required to
CC       initiate epoxidation by the downstream monooxygenase aurC
CC       (PubMed:26340065). The monooxygenase aurC and the epoxide hydrolase
CC       aurD can iteratively transform the terminal triene portion of the
CC       methylated precursor into the dioxabicyclo[3.2.1]octane scaffold of
CC       aurovertin E. Epoxidation modifications of the precursor occur in two
CC       separate steps; bis-epoxidation of the two terminal olefins takes place
CC       first, followed by another epoxidation that occurs at C7-C8 after
CC       tetrahydrofuran formation (PubMed:26340065). The O-acyltransferase aurG
CC       converts aurovertin E to aurovertin A (PubMed:26340065).
CC       {ECO:0000269|PubMed:26340065}.
CC   -!- PATHWAY: Polyketide biosynthesis. {ECO:0000269|PubMed:26340065}.
CC   -!- DISRUPTION PHENOTYPE: Blocks the production of aurovertins and
CC       accumulates the unmethylated precursor produced by the HR-PKS aurA
CC       (PubMed:26340065). {ECO:0000269|PubMed:26340065}.
CC   -!- SIMILARITY: Belongs to the methyltransferase superfamily.
CC       {ECO:0000255}.
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DR   EMBL; KT581575; ALD83628.1; -; Genomic_DNA.
DR   AlphaFoldDB; A0A0M4KDW1; -.
DR   GO; GO:0008168; F:methyltransferase activity; IEA:UniProtKB-KW.
DR   GO; GO:0032259; P:methylation; IEA:UniProtKB-KW.
DR   Gene3D; 3.40.50.150; -; 1.
DR   InterPro; IPR013217; Methyltransf_12.
DR   InterPro; IPR029063; SAM-dependent_MTases_sf.
DR   Pfam; PF08242; Methyltransf_12; 1.
DR   SUPFAM; SSF53335; SSF53335; 1.
PE   1: Evidence at protein level;
KW   Methyltransferase; Transferase.
FT   CHAIN           1..230
FT                   /note="Methyltransferase aurB"
FT                   /id="PRO_0000443966"
SQ   SEQUENCE   230 AA;  26310 MW;  139A91D2CD33EA18 CRC64;
     MTKESADNYY NPLMLWGYDV FVQVLTNSFW WRCSTKGILV PFFLDNSTTN HMEVGAGTGY
     FLRAKLDHER SKLKSSDDKT LWPQNLTLVD FHERCMNKAA NRISPVRPNR VLANIMEPIP
     LKGQKFDSIA IMYVLHCIAA TPEAKGRVFA NLKPFLADEG TLFGSTVLGK GVKHNLIGGF
     LMWLYNYIGM FDNWDDGKED FLKPLREHFE VVESEVVGTV LLFKAEKPRH