Fig. 2. (a) Putative ltb BGC for the biosynthesis of 1. Abbreviations: HR-PKS, highly reducing polyketide synthase: MT, methyltransferase; FMO-like, flavin-dependent monooxygenase-like protein; GT, glycosyltransferase; MFS transporter, major facilitator superfamily. The domains of the HR-PKS: KS, ketosynthase; AT, acyltransferase; DH, dehydratase; MT, C-methyltransferase; ER, enoylreductase; KR, ketoreductase; ACP, acyl carrier protein; cAT, carnitine O-acyltransferase domains. (b) HPLC-DAD-MS profiling of A. nidulans LO8030 expressing various combinations of ltb genes; (c) HPLC-DAD-MS profiling of A. nidulans LO8030 expressing ltbA-ΔcAT and ltbA-ΔcAT + ltbB; (d) Proposed biosynthetic pathway to luteodienoside A (1) and pathway-specific products.