The following text describes a protein:
Function:
Non-reducing polyketide synthase; part of the gene cluster that mediates the biosynthesis of cichorine, a phytotoxin active against knapweed, corn, and soybeans. The first step in the pathway is performed by the non-reducing polyketide synthase pkbA that condenses one acetyl-CoA starter unit with 3 malonyl-CoA units. PkbA also catalyzes one methylation step to produce 3-methylorsellinate. The nonribosomal peptide synthase-like protein cicB, the cytochrome P450 monooxygenase cicH and the O-methyltransferase cicE are involved in the conversion of 3-methylorsellinate into nidulol. CicB converts 3-methylorsellinate to a yet unidentified intermediate, cicH may play a ring-closing role for cichorine and cicE is plausibly responsible for the methylation of one of the phenol groups (Probable). The oxidoreductase cicC acts downstream with still unidentified enzymes to further convert nidulol into cichorin.
Domain:
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; and 2 acyl-carrier proteins (ACPs) that serve as the tether of the growing and completed polyketide via its phosphopantetheinyl arm.
Sequence:
MAPAPSALVFGSQTTLPSVEAASRLRAALLLDPRLYRMRTSIESLPEIWPALAISDPALERVAGPAEKSLRQLCRWLSHSEFPDATEISELPATFVTPFTVILHTVLYMHYTDENGSRGHADVLRAVRNNGGVQGFCTGFLTAVSVATSPDLEALSRQASVALRLAVAIGAYIDLDLLDSDVSSVAVRSRAGKKGLEETLAQFPGAYISVITDELNATVTAPRASLDALSQSLASNGLSAKRFDLRGRFHHPAHQKALEGLYNLVASNPVFQFSHSELLAPVYSNIDGQLLSSDSIIDTLLQSILVQRCDWYASISTALHKRSNGEKTSVVQFSLVECIPPSVLRQARLSVQRITDVPVQNSPATVPAPLNAVRARIQTSEPIAIIGMGCKFPGADTLDEYWQLLAQGTSMCRTMPEERFKTSSLRRSPGEKLKFWGNFVNDVDAFDHRFFKKSSREAASMDPQQRLVLQVAYQTLESAEYSGLSGIKASRDVGCYLGLCASDYTDNVASHPPNAFSSLGTLRAFLSGKISHFFGWTGPSITYDTACSSSAVAIQAACRALQTGECSMALAGGVSLYTSPNFYQNLSAASFLSPTGPTKPFDAKGDGYCRGEGVGLVFLKPLSSALADHDNIMGVIAAAAVNQNQNSTAITVPHSESQIELYRKVVSEAGLHPHDVSFVEAHGTGTPVGDPIEFTSIRTVFGGSNRANPLAIASVKGNIGHTEGAAACINNYGAAGSNAAMIVTEAPTGARSEKQGTLPKCPIYVSANTVSSLKEYCKELLRSLRGRSPDCLASLAFQLANSQNRGFPHALITSVTSKAELEDQLSAVVENRNNSLHTVAPTERPVVLAFGGQVARSVGLSRQVYDSSAVLRTHLSNCDDILTSAGLNSIFPAIFRKEPIADVVLLHSALFSAQYACAMTWIEAGVIPAALIGHSFGQLTALSVGRVLSLKDGLGLITERAKLMRDAWGPEHGSMVSVQADVQTVARLMKAAETKDPKDALEIACFNGPTSHVVVGSADAADRLEAALTQESIRYKRLAVSHGFHSKFTEPLLLGLEQCAERLTFRTPKYAIETCSSGSSWSEFNASMIVQHTRTPVYYTEALARIEAKLGACTWLEVGTGGSVAGMIRGALNVPSDHLIQAVNLAGETGTAALADATVNLWKSSHKLQFWAFHRSERECYQPLELPPYQFEKTRHWLDWKDTMTEQATVTQSTREETSVEEFLTFVKYKDSTKQQAEFRISTEHEKYSFFVKGHAVLAEPLCPAPLYIDLACKAGQMVYSDTSETLIIPSVEDLEIQAPLGVGDRVIILRLQQSPFLKTAWTFCFCSRPVMGNSAEEQLHASGTVVLRENDTKTAAEFSRFGRLVSSKRVQEMKSDPDCHILQGPVVYQLFSRVVSYADYYKGVQSVYASGAEVTGRIRLPPTVKDADTRRPLLVDNFIQTAGIHVNCLTDVGAKEVYVCTKVDRVQSAAAFTEDLANVDASWIVHSSYHPTSEKEVVNDIFVFNAATGELAMFILGAHFTRVQISSLGRVLSRANTADAAPIKVAVPVQSPALRAQPKRVLLPPLTKRSITRPTLEISEKLKKTLSRVVEVPVADIHDGGILADLGVDSLLGTEVLTEINQVFNVSIPADEFALLTDVASISKCLASYLGVHDSGSQPEDLADADSVESDSDMPTGAVTSGITTPDDAVSRLADLLAENLEYDGTIEASNNLADLGLDSILSIELANDIKKIFNCDVDMSQLNMESTFADLIALVPALNIEQSLSSVPASLTTQGSDFEMAQHAFEQIRFDYDIYTKETGFYDFWKRVYPAQSRLVLAYTVEAFAQLGCDLALMHPGDRLPKIGYLPAHEKLVQQLYNILRDGMLVATSDSGFVRSDKPVDPTSSTRLLEEINTIAPQHASEHSLLHITGSKLADCLTGTADPLNLLFRSKANRDLLAEVYLNGPMYAAISRLLCSFLGNAFSDRQSSGTFQILELGGGTGGTTGHVLDYLVRSGIPFTYTFSDVSGSFVAAARKKFAGRPYMEYQVIDIEKEPADSLTGKFHAVISTNCIHATTNLEISTGNIHRMLRPDGFVALVEFTRNMYWFDLVFGLLEGWWLFEDGRQHVIASESFWNTSMRKAGFQHVSWTDGDSFEARTLRIIAGFRAPAVNEIYTPRLDSRDTETAVESVMYKQADGIPLFADIYYPPSVSNEPRPIALMIHGGGHIMLSRKDIRPKQTAHLHTLGFLPVSIDYRLCPETTLTEGPMRDVSDAMAWARSTLCSLPLLCPGLTLDPSRVVVVGWSTGGHLAMTTAFTSIERGLSPPDAILAFYCPTDYEDRVWTQPNYPENTDVDGLSLMKYNLLEGVQDRPITAYNIPLTSRSNSKAGGTPAGGWMAPDDPRSRIVLHMNWKGQCLPVLLRGLPPSNSLSPGDAEKLISQPQPEIEEIQRVSPYAQIRRGVYRTPTFVIHGTDDDLIPYEQSVRTVQALKDMGVRAEVSVPQGKAHLFDMFKDADGSSWEVVKRGYDFLKEEVSGK