Polyketide synthase-nonribosomal peptide synthetase; part of the gene cluster that mediates the biosynthesis of wortmanamides A and B, reduced long-chain polyketides amidated with a specific omega-amino acid, 5-aminopentanoic acid (5PA) (PubMed:29343058). The PKS modules of TwmB are involved in the synthesis of the polyketide backbone, whereas the non-canonical C domain of TwmB is a bonafide condensation domain that specifically selects 5PA and catalyzes amidation to release polyketide chain (PubMed:29343058). The C domain clearly prefers C16 and C18 fatty acyl substrates, which is consistent with simultaneous formation of both octaketide and nonaketide acyl amides wortmanamides A and B (PubMed:29343058). Because TwmB lacks a designated enoylreductase (ER) domain, the required activity is provided the enoyl reductase TwmE (PubMed:29343058). The roles of the remaining enzymes have still to be clarified (Probable). 5-aminopentanoate + acetyl-CoA + 17 H(+) + 7 malonyl-CoA + 11 NADPH = 7 CO2 + 8 CoA + 6 H2O + 11 NADP(+) + wortmanamide A 5-aminopentanoate + acetyl-CoA + 20 H(+) + 8 malonyl-CoA + 13 NADPH = 8 CO2 + 9 CoA + 7 H2O + 13 NADP(+) + wortmanamide B Binds 1 phosphopantetheine covalently. Secondary metabolite biosynthesis. Interacts with TwmE. Multidomain protein; including 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 dehydratase (DH) domain that reduces hydroxyl groups to enoyl groups; an inactive methyltransferase (CMeT) domain; a ketoreductase (KR) domain that catalyzes beta-ketoreduction steps; and an acyl-carrier protein (ACP) that serves as the tether of the growing and completed polyketide via its phosphopantetheinyl arm (Probable). A C-terminal thioesterase (TE) domain that is often found in polyketide synthase proteins is not present in this protein, but TwmB contains instead a C-terminal condensation (C) domain that specifically selects 5PA and catalyzes amidation to release polyketide chain (PubMed:29343058). This C domain is a bonafide condensation enzyme despite that the second catalytic histidine in the HHxxxDG motif is substituted by proline (PubMed:29343058). Lacks an enoylreductase (ER) domain that reduces enoyl groups to alkyl group which function is performed by the trans-acting enoyl reductase TwmE.