The following text describes a protein:
Function:
Non-reducing polyketide synthase; part of the gene cluster that mediates the biosynthesis of viriditoxin, one of the 'classical' secondary metabolites produced by fungi and that has antibacterial activity. The first step is performed by the polyketide synthase VdtA which condenses one acetyl-CoA and 6 malonyl-CoA units to form the heptaketide monomer backbone of viriditoxin. The product of VdtA is then O-methylated on C7 by the O-methyltransferase VdtC. The O-methyl group is important for the stereoselective coupling of the monomers at the final step of viriditoxin biosynthesis. The short-chain dehydrogenase/reductase VdtF then acts as a stereospecific reductase converting the pyrone to dihydropyrone via the reduction of the C3-C4 double bond. The FAD-binding monooxygenase VdtE then converts the ketone group into a methyl-ester group to yield semi-viriditoxin. Finally, the laccase VdtB is involved in dimerization of 2 semi-viriditoxin molecules to yield the final viriditoxin. VdtB is responsible for the regioselective 6,6'-coupling of semi-viriditoxin, which yields (M)-viriditoxin and (P)-viriditoxin at a ratio of 1:2. The non-catalytic carboxylesterase-like protein VdtD affects the stereochemistical outcome of the coupling. The highly reducing polyketide synthase VdtX is not involved in viriditoxin synthesis, but might possibly play a role in the production of additional metabolites not identified yet.
Subcellular Localization:
Cytoplasmic vesicle. Note=The vesicles where VdtA is targeted remain unknown.
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 3 acyl-carrier protein (ACP) domains that serve as the tether of the growing and completed polyketide via its phosphopantetheinyl arm.
Sequence:
MAQKLRFYLFGDQTYDYDEQLRALLTSHDPVVRSFLERAYYTLRAEVARIPNGYQARISRFSSIAELLSQRREHGVDASLEQALTVVYQLASFMRLHSERSLSYPSADDAHCLGLCTGALSAAAVSSSRSLSELLPAAIETVILAFRTGLHASDSGRRIEESSAAAKCWSISLQGLEGHVARKLLEEWSNKKRLPPMSRPYISAYASGGVTISGPPSVLAELRNTPGLSKLRAKDIPIHAPYHSSAIFNQCDVETILSSALIDLASRATHVPILSTGTGRLVWAGTLPAAIQSALQDVLLRPISWENMSCGISTCLQSIDPSEVEVIPIATLAGPLLCRSVQVAKSQIPATIDPKNDVMNEAQSQIAEAMDRAKIAIVGMSGRFPGAENVDSLWELLMAGRDMCKEVPPTRWNVDTHVDPTGKRKNTSKIRWGCWLDNPDMFDARFFNMSPREAPQVDPAQRIALITAYEAIEQAGIVPGRTPSTQEDRVGVFFGTTSNDWCESNSGQDIDTYYIPGANRAFIPGRINYVFKFSGPSYSIDTACSSSLSALHVACNALWHGDIDTAIAGGTNVLTNPDMTAGLDRGHFLSATGNCKTFDDTADGYCRGEGVATVVLKRMDDAIADKDPILGVIRGVYTNHSAEAESITRPHVGAQKAIFQHVLNHSGIRPQDISYIEMHGTGTQAGDMREMTSVLDTFSPQYPGAIQREKPLYLGAVKSNIGHGESVSGVTALVKVIMMMQNNTIPPHRGVHTRLNRRFPSNLDERNVHIAFQATEWPRGQTPRRAFINNFSAAGGNSSVLVEDPPLILKEEGADPRSSHVIAVSAKSPSALRKNLESMRRYAMSEHTEKSLCELSYTTTARRIHHSHRLMFAGSSLEDILREMESKLAIKEPFSPCAPLQSVIFTFTGQGAQYPGMGQVFFNNFSVFRSDLCRLDDLAQKLGFPTFLPIFSASTHARLEGFTPTVVQLANTCMQLALTRLWVSWGIRPSAVVGHSIGEYAALNTAGVLSDADTVYLVGKRAQLLEEKCNRGSHTMLAALASFEKVSRLLDSAPCEVACINGPEEIVLAGPRSHMTDIQKILVAHSIRCTMLQVPFAFHSSQVDPILQDFQSAIEGVTFHKPTIPVISPLLGDFVTETGTFNPNYLARHCREPVNILQALRQASTMNLVHDSSVVMEFGPHPVVSGMVKSTLGNSIKALPTLQRNRNTWEVLTESVSTLYCMGFDINWTEYHRDFPSSQRVLRLPSYSWDLKSYWIPYRNDWTLYKGDIVPESSIALPTHQNKPHSTSPKQQAPTPILETTTLHRIVDEKSTEGTFSITCESDVSRPDLSPLVQGHKVEGIGLCTPSVYADIGFTLGNYLLDRFPTRFGPDTKVVDVTDMVIEKALMPLNAGPQLLRVTASLIWSEKEASVRFYSVDENHTETVQHSHCRIKFSDRSTYQAYQEQISAVKARMFEMKTNSSSGRTYRFNGPMAYNMVQALAEFHPDYRCIDETILDNETLEAACTVSFGNVKKEGVFHTHPGYIDGLTQSGGFVMNANDKTNLGVEVFVNHGWDSFQLYEPVTDDRSYQTHVRMRPAESNQWKGDVVVLSGENLVACVRGLTIQGVPRRVLRYILQSSAKTTQTATSSVPAPSQAPVMVPQIVQVPKAKPISQISGTLTEALRIICEQSGVPLAELTDDATFANIGVDSLLALTITSAFVEELDLDVDSSLFMDYPTVADLKRFFDKINTQHAPAPAPVSDAPKQLQPSSSPVASATPSAPIHGRSKFESVLNILTEESGVEMAGLPDSTALADIGIDSLLSLVVTSRLNDELELDVSSEDFNDCLTIRDLKAHFMSKNSDNGSSAVLTPQPSRDSALPERTRPRVADTSDEEDAPVSANEFTTSARSTSKYMAVLNIISEESGMAIEDFTDNVMFADIGIDSLLSLVIGGRIREELSFDLEVDSLFVDYPDVKGLRSFFGFESNKTATNPTASQSSSSISSGTSVFDTSPSPTDLDILTPESSLSQEEFEQPLTIATKPLPPATSVTLQGLPSKAHKILFLFPDGSGSATSYAKLPRLGADVAIIGLNSPYLMDGANMTCTFDELVTLYLTEIQRRQPAGPYHLGGWSAGGILAYRAAQILQKAAANPQKPVVESLLLLDSPPPTGLGKLPKHFFDYCDQIGIFGQGTAKAPEWLITHFQGTNSVLHEYHATPFSFGTAPRTGIIWASQTVFETRAVAPPPVRPDDTEDMKFLTERRTDFSAGSWGHMFPGTEVLIETAYGADHFSLLVSLLFRD