Fig. 5
From: Basidiomycete non-reducing polyketide synthases function independently of SAT domains
Chromatographic analysis of in vitro assays to test product formation by ArmB and ArmBΔSAT by stable-isotope labeling. The panels B-F show overlays of negative mode [M – H]− extracted ion chromatograms (EICs) of the respective reactions and controls. EICs show m/z 167 (black lanes), m/z 173 (yellow lanes), and m/z 175 (red lanes) to detect tetraketides without, or with six or eight incorporated 13C atoms. A Authentic standard of orsellinic acid (3) and structures of the tetraketide pyrone, incorporated 13C atoms are indicated by black dots. B-F Analyses of the assays and control reactions. Left column: ArmB; right column: ArmBΔSAT. B Reactions with unlabeled acetyl-CoA and [13C3]malonyl-CoA. C Reactions with [13C3]malonyl-CoA as sole substrate. D Reactions with unlabeled acetyl-CoA only. E Negative controls with heat-inactivated enzymes and unlabeled acetyl-CoA and [13C3]malonyl-CoA substrates. F Negative controls, enzymes without substrates