Highly reducing polyketide synthase; part of the gene cluster that mediates the biosynthesis of valactamides (PubMed:28604695). The first step of the pathway is performed by the highly reducing polyketide synthase valA that produces the polyketide part of the final products (Probable). An acetyl starter unit is incorporated by the ketosynthase domain of valA, and subsequently 6 malonyl-CoA-derived ketide units are incorporated and fully reduced to their respective alkane forms by the action of the ketoreductase, dehydratase, and enoylreductase domains (except for the penultimate unit, which is reduced only to the alkene) (Probable). The final five ketide units are each proposed to be alpha-methylated by the methyltransferase domain before ketone reduction by the ketoreductase domain (Probable). The C1 domain of the nonribisomal peptide synthetase valB then catalyzes amide bond formation between the heptaketide chain and L-valine (L-Val) attached to the T1 domain (Probable). The C2 domain incorporating L-isoleucine (L-Ile) then carries out chain elongation, which is followed by macrolactonization by the Ct domain to release the final product (Probable). Secondary metabolite biosynthesis. 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; a methyltransferase (CMeT) domain responsible for the incorporation of methyl groups; an enoylreductase (ER) domain that reduces enoyl groups to alkyl group; 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. Abolishes the production of valactamides A-H.