CTB1_CERBT
ID CTB1_CERBT Reviewed; 2204 AA.
AC A0A2G5IC96;
DT 17-JUN-2020, integrated into UniProtKB/Swiss-Prot.
DT 31-JAN-2018, sequence version 1.
DT 25-MAY-2022, entry version 21.
DE RecName: Full=Non-reducing polyketide synthase CTB1 {ECO:0000303|PubMed:29844193};
DE EC=2.3.1.- {ECO:0000250|UniProtKB:Q6DQW3};
DE AltName: Full=Cercosporin toxin biosynthesis cluster protein 1 {ECO:0000303|PubMed:29844193};
GN Name=CTB1 {ECO:0000303|PubMed:29844193}; ORFNames=CB0940_00833;
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], AND FUNCTION.
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: Polyketide synthase; 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:Q0UHZ9,
CC ECO:0000250|UniProtKB:Q6DQW3, ECO:0000303|PubMed:11701851}.
CC -!- CATALYTIC ACTIVITY:
CC Reaction=acetyl-CoA + 6 H(+) + 6 malonyl-CoA = 6 CO2 + 7 CoA + 2 H2O +
CC nor-toralactone; Xref=Rhea:RHEA:62892, ChEBI:CHEBI:15377,
CC ChEBI:CHEBI:15378, ChEBI:CHEBI:16526, ChEBI:CHEBI:57287,
CC ChEBI:CHEBI:57288, ChEBI:CHEBI:57384, ChEBI:CHEBI:146018;
CC Evidence={ECO:0000250|UniProtKB:Q6DQW3};
CC PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:62893;
CC Evidence={ECO:0000250|UniProtKB:Q6DQW3};
CC -!- COFACTOR:
CC Name=pantetheine 4'-phosphate; Xref=ChEBI:CHEBI:47942;
CC Evidence={ECO:0000250|UniProtKB:Q9Y8A5};
CC Note=Binds 1 phosphopantetheine covalently.
CC {ECO:0000250|UniProtKB:Q9Y8A5};
CC -!- PATHWAY: Mycotoxin biosynthesis. {ECO:0000250|UniProtKB:Q6DQW3}.
CC -!- DOMAIN: Multidomain protein; including a starter unit:ACP transacylase
CC (SAT) that selects the starter unit; a ketosynthase (KS) that catalyzes
CC repeated decarboxylative condensation to elongate the polyketide
CC backbone; a malonyl-CoA:ACP transacylase (MAT) that selects and
CC transfers the extender unit malonyl-CoA; a product template (PT) domain
CC that controls the immediate cyclization regioselectivity of the
CC reactive polyketide backbone; 2 acyl-carrier protein (ACP) domains that
CC serve as the tether of the growing and completed polyketide via its
CC phosphopantetheinyl arm; and a C-terminal thioesterase (TE) domain that
CC facilitates the release of the final product from the enzyme.
CC {ECO:0000305}.
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DR EMBL; LKMD01000100; PIB02405.1; -; Genomic_DNA.
DR AlphaFoldDB; A0A2G5IC96; -.
DR SMR; A0A2G5IC96; -.
DR OrthoDB; 68112at2759; -.
DR Proteomes; UP000230605; Chromosome 1.
DR GO; GO:0004315; F:3-oxoacyl-[acyl-carrier-protein] synthase activity; IEA:InterPro.
DR GO; GO:0031177; F:phosphopantetheine binding; IEA:InterPro.
DR GO; GO:0006633; P:fatty acid biosynthetic process; IEA:InterPro.
DR Gene3D; 1.10.1200.10; -; 2.
DR Gene3D; 3.10.129.110; -; 1.
DR Gene3D; 3.40.366.10; -; 2.
DR Gene3D; 3.40.47.10; -; 1.
DR Gene3D; 3.40.50.1820; -; 1.
DR InterPro; IPR029058; AB_hydrolase.
DR InterPro; IPR001227; Ac_transferase_dom_sf.
DR InterPro; IPR036736; ACP-like_sf.
DR InterPro; IPR014043; Acyl_transferase.
DR InterPro; IPR016035; Acyl_Trfase/lysoPLipase.
DR InterPro; IPR018201; Ketoacyl_synth_AS.
DR InterPro; IPR014031; Ketoacyl_synth_C.
DR InterPro; IPR014030; Ketoacyl_synth_N.
DR InterPro; IPR020841; PKS_Beta-ketoAc_synthase_dom.
DR InterPro; IPR020807; PKS_dehydratase.
DR InterPro; IPR042104; PKS_dehydratase_sf.
DR InterPro; IPR020806; PKS_PP-bd.
DR InterPro; IPR020802; PKS_thioesterase.
DR InterPro; IPR009081; PP-bd_ACP.
DR InterPro; IPR030918; PT_fungal_PKS.
DR InterPro; IPR032088; SAT.
DR InterPro; IPR001031; Thioesterase.
DR InterPro; IPR016039; Thiolase-like.
DR Pfam; PF00698; Acyl_transf_1; 1.
DR Pfam; PF00109; ketoacyl-synt; 1.
DR Pfam; PF02801; Ketoacyl-synt_C; 1.
DR Pfam; PF00550; PP-binding; 2.
DR Pfam; PF14765; PS-DH; 1.
DR Pfam; PF16073; SAT; 1.
DR Pfam; PF00975; Thioesterase; 1.
DR SMART; SM00827; PKS_AT; 1.
DR SMART; SM00825; PKS_KS; 1.
DR SMART; SM00823; PKS_PP; 2.
DR SMART; SM00824; PKS_TE; 1.
DR SUPFAM; SSF47336; SSF47336; 2.
DR SUPFAM; SSF52151; SSF52151; 1.
DR SUPFAM; SSF53474; SSF53474; 1.
DR SUPFAM; SSF53901; SSF53901; 1.
DR TIGRFAMs; TIGR04532; PT_fungal_PKS; 1.
DR PROSITE; PS00606; B_KETOACYL_SYNTHASE; 1.
DR PROSITE; PS50075; CARRIER; 2.
PE 3: Inferred from homology;
KW Multifunctional enzyme; Phosphopantetheine; Phosphoprotein; Repeat;
KW Transferase; Virulence.
FT CHAIN 1..2204
FT /note="Non-reducing polyketide synthase CTB1"
FT /id="PRO_0000449848"
FT DOMAIN 1679..1756
FT /note="Carrier 1"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00258"
FT DOMAIN 1783..1865
FT /note="Carrier 2"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00258"
FT REGION 11..250
FT /note="N-terminal acylcarrier protein transacylase domain
FT (SAT)"
FT /evidence="ECO:0000250|UniProtKB:Q6DQW3, ECO:0000255"
FT REGION 385..818
FT /note="Ketosynthase (KS) domain"
FT /evidence="ECO:0000250|UniProtKB:Q6DQW3, ECO:0000255"
FT REGION 923..1224
FT /note="Malonyl-CoA:ACP transacylase (MAT) domain"
FT /evidence="ECO:0000250|UniProtKB:Q6DQW3, ECO:0000255"
FT REGION 1299..1619
FT /note="Product template (PT) domain"
FT /evidence="ECO:0000250|UniProtKB:Q6DQW3, ECO:0000255"
FT REGION 1625..1674
FT /note="Disordered"
FT /evidence="ECO:0000256|SAM:MobiDB-lite"
FT REGION 1864..1931
FT /note="Disordered"
FT /evidence="ECO:0000256|SAM:MobiDB-lite"
FT REGION 1945..2195
FT /note="Thioesterase (TE) domain"
FT /evidence="ECO:0000250|UniProtKB:Q6DQW3, ECO:0000255"
FT COMPBIAS 1864..1898
FT /note="Polar residues"
FT /evidence="ECO:0000256|SAM:MobiDB-lite"
FT MOD_RES 1716
FT /note="O-(pantetheine 4'-phosphoryl)serine"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00258"
FT MOD_RES 1824
FT /note="O-(pantetheine 4'-phosphoryl)serine"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00258"
SQ SEQUENCE 2204 AA; 237775 MW; FAF213F2A7A5BEEB CRC64;
MEDGAQMRVV AFGDQTYDCS EAVSQLLRVR DDAIVVDFLE RATAVLKAEL ARLSSEQQEE
TPRFATLAEL VPRYRAGTLN PAVSQALTCI TQLGLFIRQH SSGQEAYPTA NDSCITGVCT
GALTAVAVGS ASSVTALVPL ALHTVAVAVR LGARAWEIGS CLADARRGAN GRYASWTSAV
GGISPQDLQD RISAYMTEQA LASVSVPYLS AAVGPGQSSV SAAPVILDAF LSTLLRPLTT
TRLPITAPYH APHLFTAKDV QHVTDCLPPS DAWPTVRIPI ISFSRDEAVS RGASFPAAMS
EAVRDCLIRP IALDRMAVSI ANHARDLGKD SVLPSPIALS FSDKLGPQVN SHLPGTKAPT
PELTSTSSIP SAIGAEQQPM AKSPIAILAA SGRFPQSSSM DQFWDVLING VDTHELVPPT
RWNAATHVSE DPKAKNVSGT GFGCWLHEAG EFDAAYFNMS PREAPQVDPA QRLALLTATE
VLEQAGIVPN RTSSTQKNRV GVWYGATSND WMETNSAQNV DTYFIPGGNR AFIPGRVNYF
HKFSGPSYTI DTACSSSLAA LHMACNALWR GEVDTAIVGG TNVLTNPDMT AGLDAGHFLS
RSGNCKTFDD EADGYCRGEA VVTLILKRLP DAQADKDPIQ ASILGIATNH SAEAASITRP
HAGAQQDLFQ QVLTETGLTA NDISVCEMHG TGTQAGDSGE TTSVVETLAP LNRSGSAVRT
TPLYIGAVKS NVGHAESAAG VSSLAKILLM LKHSKIPPHV GIKTKLNHRL PDLAARNTHI
ARTEVPWPRP KNGKRRVLLN NFSAAGGNTC LVLEDAPEPE DSQEVDPREH HIVALSAKTP
DSMVNNLTNM ITWIDKHSGD SIATLPQLSY TTTARRVHHR HRAVATGTDL LQIRSSLQEQ
LDRRVSGERS IPHPPNGPSF VLAFTGQGSA FEGMGVDLYK RFASFRSDIA RYDQICEGMS
LPSIKAMFED EKVFSTASPT LQQLTHVCFQ MALYRLWKSL GVQAKAVVGH SLGEYAALYA
AGVLSQSDTL YLVGRRAQLM EKHLSQGTHA MLAVRAKEEA IVAAIDGPPG EAYEFSCRNG
EQRNVLGGTV AQIQAAKAAL EAKKIRCQYL DTPMAFHTGQ VDPILPELLQ VAAACSIQDP
QIPVISPAYG KVIRSAKDFQ PEYFTHHCRS SVNMVDALQS AVEEGLLDKN IIGLEIGPGP
VVTQFVKEAV GTTMQTFASI NKDKDTWQLI TQALAKFYLA GASIEWSRYH EDFPGAQKVL
ELPAYGWTLK NYWLQYVNDW SLRKGDPAVV VAASNLELSS SIHKVITNTI TANSDGELVV
DADLSREDLH PMVQGHQVYG VPLCTPSVYA DIALTLGEYI RQVIKPGEVA QTSVEVAEMN
IQSALVANNT GRVQLLRTYA KFDPKAQVAS CTFSSIKEDG SSVVEQHANC KIRFGSLEKE
KTALESAALA AQARMAALKT QVGQDDNTYR FSKGMIYKMI GQLADFDEKY RGLCAITLDN
DAMEASGKVS FKGIPNEGKF HSSPAYLDAL SQLGGFVMNA NEGVDLEKEV FVNHGWGSMR
FFAALDPAMT YYTHVKMTQG KDKLWTGDVL IFDDKQALIG IVGGVALQGV PKRLMHYIVT
AANKKASGPP TEKKGSSPPV EKKASAPVAP TRPAIQRKNA SIPPPATQVT PQNKTIKTPS
VSALIAPALE IVSEEIGMPI DELKDDIDFT DAGLDSLLSL VISSRMRDQL GIEFESAQFM
EIGSIGGLKE FLTRLSPPVA VAVATAVEIV KEEALTSLEE LTDPSPNEIG TVWRDALKIL
SEESGLTDEE LTDDTSFADV GVDSLMSLVI TSRLRDELDI DFPDRALFEE CQTIFDLRKR
FSGSTESFDS TTTKPSAGDA TPPLTDSSAS SPPSSEFDGE TPMTDLDEVF DSPPAQKRIP
SPPKGRIPPA WSMYLQGSQK RSKEILFLFP DGAGAATSYL SLPRLGEDIG VVAFNSPFMK
TPHKFVDHTL PDVIASYVEG IRGRQAQGPY HLGGWSAGGI LAYAVAQELI AAGEEVSTLL
LIDSPSPTKG LDRLPTRFFD HCTNVGLFGT ELSRGSGGPN KTPEWLMPHF RASIELLHDY
HAPPMKLGNK TKVMVIWAGE CAFDGVRYAH IPPSAGDTDE DTEGMKFLTE KRKDFGATEW
ASLFPGTDVD ARVVESEHHF SMMRDSGAQM LVEHMRDGLG IVSS
