Highly reducing polyketide synthase; part of the gene cluster that mediates the biosynthesis of 10,11-dehydrocurvularin, a prevalent fungal phytotoxin with heat shock response and immune-modulatory activities (PubMed:26493380). The highly reducing polyketide synthase Dhc3 is responsible for biosynthesis up to the tetraketide stage (PubMed:26493380). The non-reducing polyketide synthase Dhc5 then conducts four additional chain extension cycles, producing the unreduced part of the nascent octaketide from C-1 to C-8 in 10,11-dehydrocurvularin (PubMed:26493380). Mycotoxin biosynthesis. 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 an acyl-carrier protein (ACP) that serves as the tether of the growing and completed polyketide via its phosphopantetheinyl arm (By similarity). The release of the polyketide chain from the non-reducing polyketide synthase is mediated by the thioesterase (TE) domain localized at the C-ter of the protein (By similarity).