Non-reducing polyketide synthase; part of the gene cluster that mediates the biosynthesis of macrophorins, isoprenoid epoxycyclohexenones containing cyclized drimane moieties (PubMed:28926261). The first step of the pathway is the synthesis of 6-methylsalicylic acid (6-MSA) by the polyketide synthase macA (PubMed:28926261). 6-MSA is then converted to m-cresol by the decarboxylase macB (By similarity). The cytochrome P450 monooxygenase macC then catalyzes the oxidation of m-cresol to toluquinol (By similarity). Epoxidation of toluquinol is then performed by the short chain dehydrogenase macD, with the help of macE, and a further prenylation by macG leads to 7-deacetoxyyanuthone A (By similarity). The next step is the hydroxylation of C-22 of 7-deacetoxyyanuthone A by the cytochrome P450 monooxygenase macH to yield 22-deacetylyanuthone A (By similarity). O-Mevalon transferase macI then attaches mevalon to the hydroxyl group of 22-deacetylyanuthone A to produce yanuthone E (By similarity). The terpene cyclase macJ catalyzes the cyclization of 22-deacetylyanuthone A to macrophorin A (PubMed:28926261). MacJ is also able to catalyze cyclization of yanuthone E and 7-deacetoxyyanuthone A to their corresponding macrophorins (PubMed:28926261). The macJ products can be further modified by macH and macJ, as well as by the FAD-dependent monooxygenase macF, to produce additional macrophorins, including 4'-oxomacrophorin A, 4'-oxomacrophorin D and 4'-oxomacrophorin E (PubMed:28926261). acetyl-CoA + 3 H(+) + 3 malonyl-CoA + NADPH = 6-methylsalicylate + 3 CO2 + 4 CoA + H2O + NADP(+) Secondary metabolite biosynthesis; terpenoid 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. Abolishes completely the production of macrophorin A, 4'-oxomacrophorin A, 4'-oxomacrophorin D and 4'-oxomacrophorin E. The macrophorins cluster contains a single gene insertion (encoding for the terpene cyclase macJ) compared with the yanuthone cluster that produces the linear compound yanuthone.