CTB2_CERBT
ID CTB2_CERBT Reviewed; 462 AA.
AC A0A2G5ICZ9;
DT 17-JUN-2020, integrated into UniProtKB/Swiss-Prot.
DT 31-JAN-2018, sequence version 1.
DT 03-AUG-2022, entry version 15.
DE RecName: Full=O-methyltransferase CTB2 {ECO:0000303|PubMed:29844193};
DE EC=2.1.1.- {ECO:0000250|UniProtKB:A0ST41};
DE AltName: Full=Cercosporin toxin biosynthesis cluster protein 2 {ECO:0000303|PubMed:29844193};
GN Name=CTB2 {ECO:0000303|PubMed:29844193}; ORFNames=CB0940_00832;
OS Cercospora beticola (Sugarbeet leaf spot fungus).
OC Eukaryota; Fungi; Dikarya; Ascomycota; Pezizomycotina; Dothideomycetes;
OC Dothideomycetidae; Mycosphaerellales; Mycosphaerellaceae; Cercospora.
OX NCBI_TaxID=122368;
RN [1]
RP NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA], FUNCTION, AND PATHWAY.
RC STRAIN=09-40;
RX PubMed=29844193; DOI=10.1073/pnas.1712798115;
RA de Jonge R., Ebert M.K., Huitt-Roehl C.R., Pal P., Suttle J.C.,
RA Spanner R.E., Neubauer J.D., Jurick W.M. II, Stott K.A., Secor G.A.,
RA Thomma B.P.H.J., Van de Peer Y., Townsend C.A., Bolton M.D.;
RT "Gene cluster conservation provides insight into cercosporin biosynthesis
RT and extends production to the genus Colletotrichum.";
RL Proc. Natl. Acad. Sci. U.S.A. 115:E5459-E5466(2018).
RN [2]
RP REVIEW ON CERCOSPORIN.
RX PubMed=11701851; DOI=10.1146/annurev.phyto.38.1.461;
RA Daub M.E., Ehrenshaft M.;
RT "The photoactivated cercospora toxin cercosporin: contributions to plant
RT disease and fundamental biology.";
RL Annu. Rev. Phytopathol. 38:461-490(2000).
CC -!- FUNCTION: O-methyltransferase; part of the gene cluster that mediates
CC the biosynthesis of cercosporin, a light-activated, non-host-selective
CC toxin (By similarity). The perylenequinone chromophore of cercosporin
CC absorbs light energy to attain an electronically-activated triplet
CC state and produces active oxygen species such as the hydroxyl radical,
CC superoxide, hydrogen peroxide or singlet oxygen upon reaction with
CC oxygen molecules (PubMed:11701851). These reactive oxygen species cause
CC damage to various cellular components including lipids, proteins and
CC nucleic acids (PubMed:11701851). The first step of cercosporin
CC biosynthesis is performed by the polyketide synthase CTB1 which
CC catalyzes the formation of nor-toralactone (By similarity). The starter
CC unit acyltransferase (SAT) domain of CTB1 initiates polyketide
CC extension by the selective utilization of acetyl-CoA, which is
CC elongated to the heptaketide in the beta-ketoacyl synthase (KS) domain
CC by successive condensations with six malonyl units introduced by the
CC malonyl acyltransferase (MAT) domain. The product template (PT) domain
CC catalyzes C4-C9 and C2-C11 aldol cyclizations and dehydrations to a
CC trihydroxynaphthalene, which is thought to be delivered to the
CC thioesterase (TE) domain for product release (By similarity). The
CC bifunctional enzyme CTB3 then methylates nor-toralactone to toralactone
CC before conducting an unusual oxidative aromatic ring opening (By
CC similarity). The O-methyltransferase CTB2 further methylates the
CC nascent OH-6 of the CBT3 product, blocking further oxidation at this
CC site before the reductase CTB6 reduces the 2-oxopropyl ketone at
CC position C7, giving naphthalene (By similarity). The FAD-dependent
CC monooxygenase CTB5 in concert with the multicopper oxidase CTB12 are
CC responsible for homodimerization of naphthalene with CTB7 installing
CC the dioxepine moiety, finally producing cercosporin (By similarity).
CC The fasciclin domain-containing protein CTB11 might act with CTB5 and
CC CTB12 whereas the roles of CTB9 and CTB10 have still to be elucidated
CC (By similarity). {ECO:0000250|UniProtKB:A0ST41,
CC ECO:0000250|UniProtKB:Q0UHZ9, ECO:0000303|PubMed:11701851}.
CC -!- PATHWAY: Mycotoxin biosynthesis. {ECO:0000250|UniProtKB:A0ST41}.
CC -!- SIMILARITY: Belongs to the class I-like SAM-binding methyltransferase
CC superfamily. Cation-independent O-methyltransferase family. COMT
CC subfamily. {ECO:0000305}.
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DR EMBL; LKMD01000100; PIB02404.1; -; Genomic_DNA.
DR AlphaFoldDB; A0A2G5ICZ9; -.
DR SMR; A0A2G5ICZ9; -.
DR OrthoDB; 817726at2759; -.
DR Proteomes; UP000230605; Chromosome 1.
DR GO; GO:0008171; F:O-methyltransferase activity; IEA:InterPro.
DR GO; GO:0032259; P:methylation; IEA:UniProtKB-KW.
DR Gene3D; 1.10.10.10; -; 1.
DR Gene3D; 3.40.50.150; -; 1.
DR InterPro; IPR016461; COMT-like.
DR InterPro; IPR001077; O_MeTrfase_dom.
DR InterPro; IPR029063; SAM-dependent_MTases_sf.
DR InterPro; IPR036388; WH-like_DNA-bd_sf.
DR InterPro; IPR036390; WH_DNA-bd_sf.
DR Pfam; PF00891; Methyltransf_2; 1.
DR SUPFAM; SSF46785; SSF46785; 1.
DR SUPFAM; SSF53335; SSF53335; 1.
DR PROSITE; PS51683; SAM_OMT_II; 1.
PE 3: Inferred from homology;
KW Methyltransferase; S-adenosyl-L-methionine; Transferase.
FT CHAIN 1..462
FT /note="O-methyltransferase CTB2"
FT /id="PRO_0000449854"
FT ACT_SITE 340
FT /note="Proton acceptor"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU01020"
FT BINDING 289
FT /ligand="S-adenosyl-L-methionine"
FT /ligand_id="ChEBI:CHEBI:59789"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU01020"
SQ SEQUENCE 462 AA; 50420 MW; A08CCDCD9BAEBE41 CRC64;
MANRIEADNL FELTAELVSA SAKLHKFLDQ KNLPQPSFDA PAPSVALNTA NKPYYDARSA
IVEAAEQLIR LVRGPRDTLL ALSFEHCATA SMQVVFKYKF ANHIPLHGST TYSKIAEAVG
DGVTTALVER TIQHCASFGL FETIPGGYVT HNATSSLLVT DPDLEAWMYL SAVIAYPAGA
AIPKAVEQYG VSSEATEAGY GVSIGRKIAQ FQRFREPDGK KDHEMFARAM RGIAAGGAYD
FRHAVDGGYP WHLLTEGAGH LVVDVGGGPG HVAMALAEKY PSLRFQVQDL PETVQVGAKN
CPEHLRKHVT FVAHDFMTPQ PAHEVQDGEG IVYFARFILH DWSDKYATKI VQALATGLRP
QDRIILNEVV VPEAGQVGRE TERRMHDRDL LMLMNLNGRE RTQSAFEAIF ASVTPKLRLQ
RVIHPEQGEL SLIEVTLDGV ELPAQANGVN GHANGTNGVN GH
