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Protein

Polyketide synthase CTB1

Gene

CTB1

Organism
Cercospora nicotianae (Barn spot disease fungus)
Status
Reviewed-Annotation score: -Experimental evidence at protein leveli

Functioni

Polyketide synthase; part of the gene cluster that mediates the biosynthesis of cercosporin, a light-activated, non-host-selective toxin (PubMed:12937958, PubMed:15915645, PubMed:26938470, PubMed:29610486). The perylenequinone chromophore of cercosporin absorbs light energy to attain an electronically-activated triplet state and produces active oxygen species such as the hydroxyl radical, superoxide, hydrogen peroxide or singlet oxygen upon reaction with oxygen molecules. These reactive oxygen species cause damage to various cellular components including lipids, proteins and nucleic acids (PubMed:11701851). The first step of cercosporin biosynthesis is performed by the polyketide synthase CTB1 which catalyzes the formation of nor-toralactone (PubMed:23108075, PubMed:26938470, PubMed:29610486). The starter unit acyltransferase (SAT) domain of CTB1 initiates polyketide extension by the selective utilization of acetyl-CoA, which is elongated to the heptaketide in the beta-ketoacyl synthase (KS) domain by successive condensations with six malonyl units introduced by the malonyl acyltransferase (MAT) domain. The product template (PT) domain catalyzes C4-C9 and C2-C11 aldol cyclizations and dehydrations to a trihydroxynaphthalene, which is thought to be delivered to the thioesterase (TE) domain for product release (PubMed:23108075, PubMed:29610486). The bifunctional enzyme CTB3 then methylates nor-toralactone to toralactone before conducting an unusual oxidative aromatic ring opening (PubMed:17074519, PubMed:26938470). The O-methyltransferase CTB2 further methylates the nascent OH-6 of the CBT3 product, blocking further oxidation at this site before the reductase CTB6 reduces the 2-oxopropyl ketone at position C7, giving naphthalene (PubMed:17660442, PubMed:26938470). The FAD-dependent monooxygenase CTB5 is thought to be responsible for homodimerization of naphthalene with CTB7 installing the dioxepine moiety, finally producing cercosporin (PubMed:17660442, PubMed:26938470).1 Publication7 Publications

Cofactori

pantetheine 4'-phosphateBy similarityNote: Binds 1 phosphopantetheine covalently.By similarity

Pathwayi: Mycotoxin biosynthesis

This protein is involved in Mycotoxin biosynthesis.5 Publications
View all proteins of this organism that are known to be involved in Mycotoxin biosynthesis.

GO - Molecular functioni

GO - Biological processi

Keywordsi

Molecular functionMultifunctional enzyme, Transferase
Biological processVirulence

Protein family/group databases

ESTHERicernc-q6dqw3 Thioesterase

Names & Taxonomyi

Protein namesi
Recommended name:
Polyketide synthase CTB11 Publication (EC:2.3.1.-1 Publication)
Alternative name(s):
Cercosporin toxin biosynthesis cluster protein 11 Publication
Gene namesi
Name:CTB11 Publication
OrganismiCercospora nicotianae (Barn spot disease fungus)
Taxonomic identifieri29003 [NCBI]
Taxonomic lineageiEukaryotaFungiDikaryaAscomycotaPezizomycotinaDothideomycetesDothideomycetidaeCapnodialesMycosphaerellaceaeCercospora

Pathology & Biotechi

Disruption phenotypei

Abolishes the production of cercosporin (PubMed:12937958, PubMed:15915645, PubMed:26938470). Does not display any pigmentation (PubMed:26938470). Leads to fewer necrotic lesions on inoculated tobacco leaves compared with the wild type (PubMed:15915645).3 Publications

PTM / Processingi

Molecule processing

Feature keyPosition(s)DescriptionActionsGraphical viewLength
ChainiPRO_00004449651 – 2196Polyketide synthase CTB1Add BLAST2196

Amino acid modifications

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Modified residuei1708O-(pantetheine 4'-phosphoryl)serinePROSITE-ProRule annotation1
Modified residuei1816O-(pantetheine 4'-phosphoryl)serinePROSITE-ProRule annotation1

Keywords - PTMi

Phosphopantetheine, Phosphoprotein

Expressioni

Inductioni

Expression is positively regulated by the cercosporin cluster-specific transcription factor CTB8 (PubMed:17462021). Expression is also affected by nitrogen and carbon sources and pH, and is also controlled by another transcription activator, CRG1, previously shown to regulate cercosporin production and resistance (PubMed:17462021).1 Publication

Structurei

3D structure databases

ProteinModelPortaliQ6DQW3
ModBaseiSearch...
MobiDBiSearch...

Family & Domainsi

Domains and Repeats

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Domaini1671 – 1748Carrier 1PROSITE-ProRule annotation3 PublicationsAdd BLAST78
Domaini1775 – 1857Carrier 2PROSITE-ProRule annotation3 PublicationsAdd BLAST83

Region

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Regioni11 – 250N-terminal acylcarrier protein transacylase domain (SAT)Sequence analysis3 PublicationsAdd BLAST240
Regioni384 – 817Ketosynthase (KS) domainSequence analysis3 PublicationsAdd BLAST434
Regioni922 – 1223Malonyl-CoA:ACP transacylase (MAT) domainSequence analysis3 PublicationsAdd BLAST302
Regioni1298 – 1611Product template (PT) domainSequence analysis3 PublicationsAdd BLAST314
Regioni1937 – 2187Thioesterase (TE) domainSequence analysis3 PublicationsAdd BLAST251

Domaini

Multidomain protein; including a starter unit:ACP transacylase (SAT) that selects the starter unit; a ketosynthase (KS) that catalyzes repeated decarboxylative condensation to elongate the polyketide backbone; a malonyl-CoA:ACP transacylase (MAT) that selects and transfers the extender unit malonyl-CoA; a product template (PT) domain that controls the immediate cyclization regioselectivity of the reactive polyketide backbone; 2 acyl-carrier protein (ACP) domains that serve as the tether of the growing and completed polyketide via its phosphopantetheinyl arm; and a C-terminal thioesterase (TE) domain that facilitates the release of the final product from the enzyme.3 Publications

Keywords - Domaini

Repeat

Family and domain databases

Gene3Di1.10.1200.10, 2 hits
3.40.366.10, 1 hit
3.40.47.10, 1 hit
3.40.50.1820, 1 hit
InterProiView protein in InterPro
IPR029058 AB_hydrolase
IPR001227 Ac_transferase_dom_sf
IPR036736 ACP-like_sf
IPR014043 Acyl_transferase
IPR016035 Acyl_Trfase/lysoPLipase
IPR018201 Ketoacyl_synth_AS
IPR014031 Ketoacyl_synth_C
IPR014030 Ketoacyl_synth_N
IPR016036 Malonyl_transacylase_ACP-bd
IPR020801 PKS_acyl_transferase
IPR020841 PKS_Beta-ketoAc_synthase_dom
IPR020807 PKS_dehydratase
IPR020806 PKS_PP-bd
IPR020802 PKS_thioesterase
IPR009081 PP-bd_ACP
IPR030918 PT_fungal_PKS
IPR032088 SAT
IPR001031 Thioesterase
IPR016039 Thiolase-like
PfamiView protein in Pfam
PF00698 Acyl_transf_1, 1 hit
PF00109 ketoacyl-synt, 1 hit
PF02801 Ketoacyl-synt_C, 1 hit
PF00550 PP-binding, 2 hits
PF14765 PS-DH, 1 hit
PF16073 SAT, 1 hit
PF00975 Thioesterase, 1 hit
SMARTiView protein in SMART
SM00827 PKS_AT, 1 hit
SM00825 PKS_KS, 1 hit
SM00823 PKS_PP, 2 hits
SM00824 PKS_TE, 1 hit
SUPFAMiSSF47336 SSF47336, 2 hits
SSF52151 SSF52151, 2 hits
SSF53474 SSF53474, 2 hits
SSF53901 SSF53901, 1 hit
SSF55048 SSF55048, 1 hit
TIGRFAMsiTIGR04532 PT_fungal_PKS, 1 hit
PROSITEiView protein in PROSITE
PS00606 B_KETOACYL_SYNTHASE, 1 hit
PS50075 CARRIER, 2 hits

Sequencei

Sequence statusi: Complete.

Q6DQW3-1 [UniParc]FASTAAdd to basket
« Hide
        10         20         30         40         50
MEDGAQMRVV AFGDQTYDCS EAVSQLLRVR DDAIVVDFLE RAPAVLKAEL
60 70 80 90 100
ARLSSEQQEE TPRFATLAEL VPRYRAGTLN PAVSQALTCI AQLGLFIRQH
110 120 130 140 150
SSGQEAYPTA HDSCITGVCT GALTAVAVGS ASSVTALVPL ALHTVAVAVR
160 170 180 190 200
LGARAWEIGS CLADARRGAN GRYASWTSAV GGISPQDLQD RISAYTAEQA
210 220 230 240 250
LASVSVPYLS AAVGPGQSSV SAAPVILDAF LSTLLRPLTT TRLPITAPYH
260 270 280 290 300
APHLFTAKDV QHVTDCLPPS EAWPTVRIPI ISFSRDEAVS RGASFPAAMS
310 320 330 340 350
EAVRDCLIRP IALDRMAVSI TNHARDLGKD SVLPSPIALS FSDKLGPQVN
360 370 380 390 400
SHLPGAKAPT PELTSKSIPS AIGAEQQPMA KSPIAILAAS GRFPQSSSMD
410 420 430 440 450
QFWDVLINGV DTHELVPPTR WNAATHVSED PKAKNVSGTG FGCWLHEAGE
460 470 480 490 500
FDAAYFNMSP REAPQVDPAQ RLALLTATEA LEQAGVVPNR TSSTQKNRVG
510 520 530 540 550
VWYGATSNDW METNSAQNVD TYFIPGGNRA FIPGRVNYFH KFSGPSYTID
560 570 580 590 600
TACSSSLAAL HMACNALWRG EVDTAIVGGT NVLTNPDMTA GLDAGHFLSR
610 620 630 640 650
SGNCKTFDDE ADGYCRGEAV VTLILKRLPD AQADKDPIQA SILGIATNHS
660 670 680 690 700
AEAASITRPH AGAQQDLFQQ VLTETGLTAN DISVCEMHGT GTQAGDSGET
710 720 730 740 750
TSVVETLAPL NRSGSAVRTT PLYIGAVKSN VGHAESAAGV SSLAKILLML
760 770 780 790 800
KHSKIPPHVG IKTKLNHRLP DLAARNTHIA RSEVPWPRPK NGKRRVLLNN
810 820 830 840 850
FSAAGGNTCL VLEDAPEPED SQEVDPREHH IVALSAKTPD SMVNNLTNMI
860 870 880 890 900
TWIDKHSGDS LATLPQLSYT TTARRVHHRH RAVATGTDLL QIRSSLQEQL
910 920 930 940 950
DRRVSGERSI PHPPNGPSFV LAFTGQGSAF AGMGVDLYKR FASFRSDIAR
960 970 980 990 1000
YDQICEGMSL PSIKAMFEDE KVFSTASPTL QQLTHVCFQM ALYRLWKSLG
1010 1020 1030 1040 1050
VQAKAVVGHS LGEYAALYAA GVLSQSDTLY LVGRRAQLME KHLSQGTHAM
1060 1070 1080 1090 1100
LAVRAKEEAI VAAIDGPPGE AYEFSCRNGE QRNVLGGTVA QIQAAKAALE
1110 1120 1130 1140 1150
AKKIRCQYLD TPMAFHTGQV DPILPELLQV AAACSIQDPQ IPVISPAYGK
1160 1170 1180 1190 1200
VIRSAKDFQP EYFTHHCRSS VNMVDALQSA VEEGLLDKNV IGLEIGPGPV
1210 1220 1230 1240 1250
VTQFVKEAVG TTMQTFASIN KDKDTWQLMT QALAKFYLAG ASVEWSRYHE
1260 1270 1280 1290 1300
DFPGAQKVLE LPAYGWALKN YWLQYVNDWS LRKGDPAVVV AASNLELSSS
1310 1320 1330 1340 1350
IHKVITNTIT ANSDGELVVD ADLSREDLHP MVQGHQVYGV PLCTPSVYAD
1360 1370 1380 1390 1400
IALTLGEYIR QVIKPGEVAQ TSVEVAEMNI QSALVANNTG RVQLLRTCAK
1410 1420 1430 1440 1450
FDPKAQVASC TFSSIVEQHA NCKIRFGSLE KEKTALKSAA LAAQASMAAL
1460 1470 1480 1490 1500
KTQVGQDDNT YRFSKGMIYK MIGQLADFDE KYRGLCAITL DNDAMEASGK
1510 1520 1530 1540 1550
VSFKGIPNEG KFHSSPAYLD ALSQLGGFVM NANEGVDLEK EVFVNHGWGS
1560 1570 1580 1590 1600
MRFFAALDPA MTYYTHVKMT QGKDKLWTGD VLIFDDKQAL IGIVGGVALQ
1610 1620 1630 1640 1650
GVPKRLMHYI VTAANKKASG PPTEKKTSSP PVEKKASAPV APTRPAIQRK
1660 1670 1680 1690 1700
NASIPPPATQ VTPQNKTIKT PSVSALIAPA LEIVSEEIRM PIDELKDDID
1710 1720 1730 1740 1750
FTDAGLDSLL SLVISSRMRD QLGIEFESAQ FMEIGSIGGL KEFLTRLSPP
1760 1770 1780 1790 1800
VAVAVATAVE IVKEEALTSL EELTDPSPNE IGTVWRDALK ILSEESGLTD
1810 1820 1830 1840 1850
EELTDDTSFA DVGVDSLMSL VITSRLRDEL DIDFPDRALF EECQTIFDLR
1860 1870 1880 1890 1900
KRFSGSTESF DSTTTKPSAG DATPPLTDSS ASSPPSSEFD GETPMTDLDE
1910 1920 1930 1940 1950
VFDSPPAQKR IPSPPKGRIP PAWSMYLQGS QKRSKEILFL FPDGAGAATS
1960 1970 1980 1990 2000
YLSLPRLGED IGVVAFNSPF MKTPHKFADH TLPDVIASYV EGIRGRQAQG
2010 2020 2030 2040 2050
PYHLGGWSAG GILAYAVAQE LIAAGEEVST LLLIDSPSPT KGLDRLPTRF
2060 2070 2080 2090 2100
FDHCTNVGLF GTELSRGSGG PNKTPEWLMP HFRASIELLH GYHAPPMKLG
2110 2120 2130 2140 2150
NKTKVMVIWA GECAFDGVRY AHIPPSAGDT DEDTEGMKFL TEKRKDFGAT
2160 2170 2180 2190
EWASLFPGTD VDARVVESEH HFSMMRDSGA QMLVEHMRDG LGIVSS
Length:2,196
Mass (Da):236,728
Last modified:August 16, 2004 - v1
Checksum:iB6F633E98FB4BE16
GO

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
AY649543 mRNA Translation: AAT69682.1

Similar proteinsi

Cross-referencesi

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
AY649543 mRNA Translation: AAT69682.1

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
PDB entryMethodResolution (Å)ChainPositionsPDBsum
6FIJX-ray2.77A/B1-1293[»]
6FIKelectron microscopy7.10A/B1-1293[»]
C1775-1858[»]
ProteinModelPortaliQ6DQW3
ModBaseiSearch...
MobiDBiSearch...

Protein family/group databases

ESTHERicernc-q6dqw3 Thioesterase

Protocols and materials databases

Structural Biology KnowledgebaseSearch...

Family and domain databases

Gene3Di1.10.1200.10, 2 hits
3.40.366.10, 1 hit
3.40.47.10, 1 hit
3.40.50.1820, 1 hit
InterProiView protein in InterPro
IPR029058 AB_hydrolase
IPR001227 Ac_transferase_dom_sf
IPR036736 ACP-like_sf
IPR014043 Acyl_transferase
IPR016035 Acyl_Trfase/lysoPLipase
IPR018201 Ketoacyl_synth_AS
IPR014031 Ketoacyl_synth_C
IPR014030 Ketoacyl_synth_N
IPR016036 Malonyl_transacylase_ACP-bd
IPR020801 PKS_acyl_transferase
IPR020841 PKS_Beta-ketoAc_synthase_dom
IPR020807 PKS_dehydratase
IPR020806 PKS_PP-bd
IPR020802 PKS_thioesterase
IPR009081 PP-bd_ACP
IPR030918 PT_fungal_PKS
IPR032088 SAT
IPR001031 Thioesterase
IPR016039 Thiolase-like
PfamiView protein in Pfam
PF00698 Acyl_transf_1, 1 hit
PF00109 ketoacyl-synt, 1 hit
PF02801 Ketoacyl-synt_C, 1 hit
PF00550 PP-binding, 2 hits
PF14765 PS-DH, 1 hit
PF16073 SAT, 1 hit
PF00975 Thioesterase, 1 hit
SMARTiView protein in SMART
SM00827 PKS_AT, 1 hit
SM00825 PKS_KS, 1 hit
SM00823 PKS_PP, 2 hits
SM00824 PKS_TE, 1 hit
SUPFAMiSSF47336 SSF47336, 2 hits
SSF52151 SSF52151, 2 hits
SSF53474 SSF53474, 2 hits
SSF53901 SSF53901, 1 hit
SSF55048 SSF55048, 1 hit
TIGRFAMsiTIGR04532 PT_fungal_PKS, 1 hit
PROSITEiView protein in PROSITE
PS00606 B_KETOACYL_SYNTHASE, 1 hit
PS50075 CARRIER, 2 hits
ProtoNetiSearch...

Entry informationi

Entry nameiCTB1_CERNC
AccessioniPrimary (citable) accession number: Q6DQW3
Entry historyiIntegrated into UniProtKB/Swiss-Prot: September 12, 2018
Last sequence update: August 16, 2004
Last modified: September 12, 2018
This is version 81 of the entry and version 1 of the sequence. See complete history.
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programFungal Protein Annotation Program

Miscellaneousi

Keywords - Technical termi

3D-structure
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Main funding by: National Institutes of Health

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